Site Selection Story, 2006–2012: Decision

Abstract

The previous chapter described the first three stages of site selection from 1994 to 2006. This took the reader from early national initiatives in China and Australia, to centrally coordinated activity to identify and characterise these and two other potential sites in Southern Africa and South America (Argentina together with Brazil), to the creation of a shortlist of two potential hosts, Australia and Southern Africa, in 2006.

This chapter continues the story to its culmination in 2012 when the SKA governing body decided to locate the mid-frequency dish array in Southern Africa and the low-frequency array in Australia. The complex site decision process is described and analysed in detail, as is the evaluation of the hosting proposals by expert consultants and panels and by an external SKA Site Advisory Committee. The final stage leading to the site decision in 2012 was a time of considerable tension in the project, not least due to the site selection process having become highly political.

8.1 Introduction

By the end of the short-listing process in August 2006, described in the previous chapter, it would be fair to say that most people expected Australia eventually to win the site competition. However, the process to arrive at the final site selection was not at all clear. How long would/should it take? Should site selection be carried out before the technical design was finalised? How much additional site characterisation would be required? How would the site negotiations be carried out? What roles would the funding agencies and the International SKA Steering Committee (ISSC) play? The governing principle was, however, clear—the final selection process should be conducted in a timely, transparent and considered manner.

The ISSC assumed it would evaluate all selection criteria and make a recommendation to the funding agencies who would then carry out negotiations with the recommended site. From the ISSC point of view it was very much a winner-takes-all scenario. In subsequent years, the roles of the ISSC and its successor, the SKA Science and Engineering Committee (SESC), and the funding agencies in the site selection decision became better defined and, jointly, a process was established with buy-in from the two candidate sites that for the most part was carried out satisfactorily. However, both candidate sites hedged their bets by initiating large precursor projects (see Sect. 4.3.3) as a scientifically valuable back-up if they did not win the competition. In Australia, the leadership saw the precursor, ASKAP, as essential in influencing the site decision and that led to considerable time pressure on the ASKAP design such that construction began before the design was completed. This was not the case for MeerKAT in South Africa as the KAT-7 interferometer was seen as being sufficient to demonstrate the Karoo site’s potential. In the event, the national investment in infrastructure and know-how in the pre-cursors became a significant argument influencing the final decision by the Board of Directors and Members of the SKA Organisation (SKAO) to utilise both sites for the SKA, a result that was unexpected at the start of the final selection process in late-2006.

During the site decision process, there were many communication and reporting channels established among the funding agencies groups, the steering committee (ISSC, SSEC), the central project office (ISPO, SPDO), the PrepSKA Board overseeing the site characterisation activities led by the SPDO, the site decision-specific committees formed towards the end of the process (SKA Siting Group, SSG, and SKA Site Advisory Committee, SSAC), and the candidate SKA sites (Australia and South Africa). Figure 8.1 shows the players in the site decision process and the communication and reporting channels linking them.

Fig. 8.1

The players in the SKA site decision process and many of the communication and reporting channels established as part of the process. Communication channels are indicated by double-ended arrows, reporting channels by single-ended arrows. The dashed boxes in the Candidate SKA Sites column include the ensemble of entities that were in communication with the two sites during the periods depicted in the top two panels. Acronyms used in the figure are: FAWG Funding Agencies Working Group, ASG Agencies SKA Group, FB Founding Board, ISSC International SKA Steering Committee, SSEC SKA Science and Engineering Committee, ISPO International SKA Project Office, SKAO SKA Organisation, SPDO SKA Program Development Office, PrepSKA Preparatory Phase for the SKA, SSG SKA Siting Group, and SSAC SKA Site Advisory Committee

The main elements of the story from 2006 to 2012 are the players and their interactions, the tortuous path towards an acceptable date for the site selection and an acceptable selection process, the further characterisation of the sites and difficulties encountered, preparation for the final site submissions, the evaluation of the proposals, and finally the decision. This was all played out against a backdrop of competing national interests both within the project and at high political level internationally, and self-imposed constraints of tight schedules for both the SKA project as a whole and the precursors.

We go through these elements in this chapter.

8.2 Timing of the Site Decision

8.2.1 Revised Goal: 2008

Prior to the first consideration of SKA by the funding agencies at Heathrow airport in June 2005, ISSC discussions of the project timeline foresaw final selection of the site in 2006 (see Sect. 7.3.7.1). At Heathrow, the funding agencies made it clear that site selection was an aspect in which they would need to be involved. This led the ISSC to modify its position in August 2005¹ from an outright selection to a ranked list of the four potential sites in 2006 followed by further characterisation of the physical characteristics and RFI environment of the sites. Finally, round-table discussions involving the ISSC, funding agencies and potential sites on scientific and geo-political issues, would take place prior to a decision by the end of 2008. Thereafter, preparation and roll-out of site infrastructure would take place in 2009–10 followed by start of SKA Phase 1 construction in 2011.

The Hague meeting of funding agencies in February 2006 (see Sects. 3.4.3 and 7.3.7.2) clarified their involvement in the site selection process and this led to a shift in the ISSC position from the ranked list of potential sites to a short-list of acceptable sites. The ISSC also modified its concept of a subsequent “round-table discussion” to “international negotiations” but left the final decision on the site as late-2008 in order to maintain the goal of a construction start in 2011.

8.2.2 Second Revision: 2010

However, at their meeting in Prague at the IAU General Assembly in August 2006, the Funding Agencies Working Group (FAWG) made it clear that the ISPO and ISSC was too focussed on maintaining the 2011 construction start goal at the expense of considering the details of achieving the milestones on the way. There was broad support for the views of the Australian delegate, Martin Gallagher, that site selection in 2008 was optimistic and incompatible with project approval practice in the various countries likely to be involved in the SKA. Site selection in 2009 or 2010 appeared more realistic from their point of view.

Discussion of the FAWG view by the ISSC in the succeeding months produced no strong arguments to maintain the 2008 date, despite an initial clear majority for pushing back on this to the funding agencies in a non-confrontational way.² And in November 2006, the ISSC finally accepted that the final site selection, technology procurement, and governance decisions for the SKA were inextricably linked, and produced a landmark strategy paper³ that proposed the SKA site selection decision be set to not later than 2010 to best match the international funding opportunities and perceived decision-making time scales. The ISSC also noted that despite the development of precursors at the proposed sites, a final site choice by 2010 would need to take into account the time required to build up initial SKA-specific infrastructure in addition to that in place for the precursors.

During 2007 and 2008, site-related discussions in the ISSC, and subsequently the SSEC, focussed on the more practical concerns of the additional site characterisation studies to be carried out in PrepSKA Work Package 3. As discussed in Sect. 8.4, these studies included RFI monitoring and tropospheric monitoring, as well as formal recognition of radio-quiet zones around the candidate SKA sites in both countries. As far as site infrastructure was concerned, a report from a Tiger Team led by the SKA Project Engineer, Peter Hall, (CSIRO, Australia) concluded that 3–4 years would be required to develop a “green-field” site, but with re-use of the associated precursor site infrastructure for SKA Phase 1 construction, development times as short as 2 years were possible. The latter would still allow a construction start in 2012.

At the same time, the funding agencies were taking the first steps towards consensus on a decision-making framework that would serve the project in the implementation phase following PrepSKA as well as coming to grips with their responsibilities for the three ‘Policy’ work packages in PrepSKA (see Sect. 4.4.1). Arguments for the 2010 site selection continued to be refined and now included the expectation that SKA project would have a clearer focus as a whole which could allow the scope of the precursor telescope construction on the selected site (ASKAP in Australia or MeerKAT in South Africa) to be reduced thus freeing up additional resources for the international design effort. Also planning for SKA infrastructure could begin earlier.

8.2.3 Third and Final Revision: 2012

The 2010 site selection date did not hold. In 2009, the SSEC and the funding agencies returned to the site selection date after further examination by the SSEC of the project-wide interim milestones leading to the start of SKA Phase 1 construction. This resulted in the adoption of a revised milestone of mid-2011 for the SSEC recommendation on the preferred site and a final decision by the funding agencies and governments in 2012.^4,5,6

The arguments supporting this further delay were threefold: (i) it was not clear that governments, funding agencies and the SSEC would have sufficient information to make a choice in 2010 which would be well before further characterisation of the candidate sites was completed in PrepSKA; (ii) it was not clear whether any SKA-specific site development would take place before there was a commitment at government level to construct the SKA; and (iii) a 2011 date for the SSEC recommendation would allow governments and funding agencies to discuss options for governance, procurement, and funding resulting from the PrepSKA policy work packages in conjunction with the SSEC recommendation, before making the final site decision.

This was the final revision of the site decision timeline.

8.3 Developing the Site Selection Process

8.3.1 Slow Steps at the Start, 2007–2008

As far as the selection process itself was concerned, the FAWG noted in May 2007 that there was an urgent need for discussions on several key decision areas including the process and timescale for deciding on the eventual site for the SKA. A decision on the site would need to be made in 2009 or 2010 if the construction of the SKA Phase 1 array was to begin in 2012, given the lead times for the selection of the site, installation of infrastructure on the site, establishment of an appropriate management capacity and structure, and development of a funding plan for the Phase 1 array before construction could start.

However, this urgency did not translate into concrete action on the site selection process until October 2009 due to the arrival of the PrepSKA funding in 2008 and the need for the funding agencies to map out their approach to the policy work packages - governance, procurement, and funding - for which they had responsibility.

Also required on the part of the funding agencies was a strategy for interaction with the whole SKA project, including the site selection process. To accomplish this, the funding agencies continued, in parallel with their PrepSKA workshops, to hold meetings to review project progress and align the project with agency thinking on timescales including that of site selection as well as funding and implementation scenarios. In November 2008 in a meeting in Washington D. C., the Funding agency representatives discussed the broad concepts behind developing a selection process and used the European Spallation Source as an example to suggest that an external expert group could be employed to make factual recommendations. In SKA’s case, these factual recommendations would be based on the results of PrepSKA Work Package 2 (telescope design) and 3 (site characterisation). Other factors including political aspects, already existing infrastructure and operations support issues would need to be considered. Some funding agency participants felt that site selection should be decided by science and engineering considerations rather than by externally primarily politically driven influences. However, the consensus view was that the SSEC was the appropriate body to receive the technical site evaluation reports and to recommend a site based on technical merit to the funding agencies.

A concrete outcome from the Washington discussion a few months later was the first version of an SSEC document outlining current thinking on the site selection process. Further development of this pivotal document⁷ took place at succeeding SSEC and funding agency meetings, both separate and joint, in the first half of 2009, and underpinned the site deliberations throughout the following 3 years until the decision. We now discuss the main points in more detail.

8.3.2 SSEC Views on Site Selection Issues

The SSEC document set out the defining physical characteristics of a desirable SKA site, the likely selection criteria, timescales for infrastructure development, and noted two over-arching considerations—that site selection and approval of construction funding were linked, and that the site selected for SKA Phase 1 (10% of the final SKA collecting area) must be able to accommodate the construction of the full SKA array (SKA Phase 2). Unresolved issues were also addressed, amongst which were when could or should the site decision be made (see previous section), how would the decision be made and what were the potential outcomes of the decision process.

8.3.2.1 How the Site Decision Would Be Made

In mid-2009, it was generally understood by the Agencies and the SSEC that the SSEC would evaluate all selection criteria including infrastructure capital costs, operations costs, decommissioning costs and national attributes, and then make a motivated recommendation to the governments and funding agencies for ratification. The SSEC document noted that the governments and funding agencies must by then have established a process for making decisions on the SKA. (Unknown to the SSEC at the time, the IFAG-ASG was in fact spending considerable time in closed session meetings coming to a consensus on a decision-making structure for the project as a whole, as described in Sect. 4.6.)

The SSEC recognised that if they were unable to make a clear recommendation, a process of negotiation organised by governments and funding agencies would need to be initiated in which additional criteria for selection might need identification and agreement. Examples of additional criteria were the level and timeliness of the host country contribution to the project, and the level of support around the world for one or the other country. In the event, the over-riding post-recommendation issue was how to keep both candidate countries involved in the project.

8.3.2.2 Potential Outcomes of the Site Selection Process

Two potential outcomes were discussed:

• 1. “Winner takes all”

Under this scenario, the selected country hosts the SKA. The non-selected country continues to develop its precursor array, and hopefully continues to contribute to the realisation of the SKA scientifically, technically, and as a supplier of technology or services to the SKA.

• 2. “Win-win”

The selected country hosts the SKA, but a large remote station for the SKA is installed in the non-selected country to contribute even longer baselines to the SKA for high angular resolution observations, matching typical Very-Long-Baseline Interferometry measurements. It would be up to the non-selected country to decide whether to continue development of its precursor array. The SSEC document noted that the scientific merit of a large remote station 6000 km from the SKA core needed further discussion.

Alternatively, the SKA could be divided between the two countries, with Phase 1 and Phase 2 of SKA-low (70–500 MHz) in one country, and Phase 1 and Phase 2 of SKA-mid (300 MHz—10 GHz) in the other. Under this scenario, governments and funding agencies would have to foot the bill for the complete infrastructure, operating, and decommissioning costs in the two locations. Initial estimates of the capital costs of infrastructure on one site were €200 M⁸ meaning the capital costs of the SKA would go up by an extra ~€200 M in the two-site scenario, and there would be additional operating costs.

Three additional caveats were noted: the “extra” €200 M figure was uncertain in part because the infrastructure costs of the low-frequency array could be lower. A benign RFI environment was of greater importance for the low-frequency array than at higher frequencies. Finally, it was realised there might be scientific ramifications to decoupling the locations of the low and mid-frequency telescopes for transient source investigations, but this would need to be studied. Not mentioned in the SSEC document was an additional, industrial ramification - the ‘winning’ site(s) would become the default suppliers of infrastructure works.

8.3.3 SKA Siting Group, October 2009–March 2011 and how the Funding Agencies Took Ownership of the Selection Process

In its meeting in July 2009,⁹ the ASG recognised it would need to drive discussions on defining a process for site selection discussion as this was a clear ‘threshold issue’ for progress with the project.

This came to pass in October 2009¹⁰ when the ASG joined the battle with all guns blazing. John Womersley (ASG chair, STFC, UK) made it clear to a joint meeting of the ASG and SSEC that site selection was an area where both groups needed to work together closely to agree on the selection processes and their milestones. He noted that selection must be informed by a rational scientific/technical recommendation that would be incorporated into a wider and probably more political decision process. “With a well-defined process, the ‘losers’ should feel disappointed but not in any way cheated.” (See comments in Box 8.1).

Box 8.1 The Language of International Meetings

Some thought was given to avoiding emotive terminology in international meetings on the SKA, not always with success.

Some examples

• (i) In its August 2006 meeting to select the site short-list (see Sect. 7.3.8.2), ISSC members agreed to replace earlier use of “fatal flaw” by “disabling characteristic” to describe a characteristic that made it impossible to choose the site.

• (ii) In preparation for the February 2006 Funding Agencies-ISSC meeting in The Hague, the ISSC used the neutral term “negotiation” to describe discussions following a ranking of acceptable sites (see Sect. 7.3.7.2. At the end of the Hague meeting, the chair of the Funding Agencies Group used the colourful term “blood on the floor” to describe the style of negotiation expected among the sites on a short-list (see Sects. 3.4.3 and 7.3.7.2).

• (iii) Despite having effectively created a two-horse race to select the site in 2006 (see ii) above), the Agencies SKA Group (ASG), at its July 2009 meeting, disparaged “winner-loser” terminology in the 2009 SSEC document discussing possible outcomes of the site selection process (reference 1 below). The ASG noted that the use of the words “win” and “winner” in site discussions was not helpful, since it implied that there was a “loser” (reference 2 below). However, in what was no doubt a slip of the tongue, the ASG chair still used the word “loser” in remarks about site selection outcomes at the subsequent ASG meeting in October 2009 reference 3 below).

References

• 1. hba.skao.int/SKAHB-451 On the Selection of the Site for the SKA, SSEC, paper for the 3rd SSEC Meeting, June 2009

• 2. hba.skao.int/SKAHB-453 Minutes of the ASG meeting, July 2009

• 3. hba.skao.int/SKAHB-454 Minutes of the ASG meeting, October 2009

Vernon Pankonin (US National Science Foundation) outlined the first thoughts on an ASG-SSEC working group for SKA Siting based on information from the European Spallation Source (ESS) project. It was clear from the outset that this SKA Siting Group would define the site decision-making process but not make the decision itself.

The ASG felt that strong leadership of the site selection process was essential, co-chairs were to be avoided, and that the ASG should provide the chair.¹¹ This flowed from earlier internal discussions on governance and decision-making in the ASG where concern was expressed about a risk of conflict if the SSEC and ASG had different ideas about the evolution of the current governance towards the final governance and decision-making in the SKA program. The ASG concluded that the roles and responsibilities in the (evolution) process should be explicitly agreed with the SSEC, particularly with respect to long-term governance, project funding and the site selection process, all three of which the ASG felt were their responsibility.

Despite lingering concerns from some members of the SSEC (see Box 8.2) there was no argument from the SSEC as a whole on this score.

Box 8.2 SSEC Thoughts on Site Selection Process

Ken Kellermann (National Radio Astronomy Observatory, USA), 1 February 2010, in a Memo to Vernon Pankonin and colleagues on the draft Terms of Reference for the SKA Siting Group (see reference 1 below).

‘My biggest concern is that the choice of site for the SKA be made by the project on the basis of what is considered to be best for the SKA, and to the extent possible that we defuse any sense of a competition or contest between Australia and South Africa. …  As I believe normal for activities of this kind, the project management (SSEC, ASG, and SPDO) should be responsible for acquiring all relevant data on site suitability, and not rely on reports, advertizing, or lobbying by the site proponents. We are not conducting a contest. Outside advice by experts experienced in various areas of site selection will be valuable and will be needed to inform the recommendation; but they should not make any recommendation or decision. The responsibility for a recommendation is with the SKA project which will have to live with it, and I do not believe that it will be appropriate to delegate this responsibility to an external group or to governments.’

Michael Garrett, (ASTRON, The Netherlands) comments at an SSEC Executive Committee, March 2010 (see reference 2 below).

Garrett noted that the influence of the ASG on the site recommendation is a sensitive matter.

References

• 1. hba.skao.int/SKAHB-96 Kellermann, K., I., Comments on the Pankonin Committee Draft Terms of Reference for the SKA Siting Group

• 2. hba.skao.int/SKAHB-97 Garrett, M. A., Minutes of the SSEC Executive Committee, March 2010

In subsequent months, initial Terms of Reference for the SKA Siting Group¹² were drafted by Pankonin with feedback from Bernie Fanaroff (SKA South Africa), Martin Gallagher (Australian Government), Ken Kellermann (SSEC), Elena Righi-Steele (European Commission), Richard Schilizzi (SKA Director), and Yervant Terzian (SSEC) and discussed at some length in March and June 2010 in funding agency and SSEC meetings. The proposed membership structure caused little controversy, but this was not the case for the proposed objectives and working approach.

On membership, it would be a small group—the SKA Siting Group (SSG)—coordinating the process with equal representation, three each, from the ASG and the SSEC, the SKA Director as a non-voting adjunct member, and liaison contacts in both candidate site countries (see Box 8.3). Members of the SSG were to be acceptable to both candidate host countries, and countries directly involved with the two site proposals could not be SSG members.

Box 8.3 SSG Membership

Agencies SKA Group: Simon Berry (Science and Technology Facilities Council, UK), Vernon Pankonin—Chair (National Science Foundation, USA), and Patricia Vogel (Netherlands Organisation for Scientific Research).

SKA Science and Engineering Committee: Russ Taylor (University of Calgary, Canada), Yervant Terzian (Cornell University, USA), and Anton Zensus (Max Planck Institute for Radioastronomy, Germany).

Adjunct member: Richard Schilizzi (SKA Director).

Site Resource Liaisons: Australia: Michelle Storey (CSIRO), Brian Boyle (CSIRO); South Africa: Bernard Fanaroff (SKA South Africa), Adrian Tiplady (SKA South Africa).

Argument did come from the SSEC at the March 2010 meeting on the objectives of the SSG (see Box 8.4), the fourth objective in particular. While there was no dispute that individual SSG members could not serve on both the body making the site recommendation and the one making the decision—put succinctly by Womersley as ‘It is not good practice for a body to make recommendations to itself’—there was dispute about the body to make the motivated recommendation. With the successful short-listing process managed by the ISSC in 2006 in mind, the SSEC had long thought it would assume a similar role in the final stage of site selection and argued for this against the alternative of the SSG or the SSG augmented by a ‘Site Evaluation Committee’ (SEC) whose members would be selected for their expertise and experience in selecting sites for international scientific facilities, in particular astronomy facilities, and for their independence from governmental bodies and from candidate site host countries. SSEC members and the SKA Director pointed out that the SSEC had greater knowledge and experience of the SKA than the SSG or SSG + SAC and should be responsible for the science and engineering recommendation.

Box 8.4 SSG Objectives

Initial (October 2009)

• 1. Establish a roadmap to site selection, and direct and oversee the implementation of the roadmap up to the issuance of the report and possible recommendation that is based on the comparative evaluation of the sites.

• 2. Establish scientific and technical criteria and more broadly based selection factors applicable to both sites to be used for identifying a preferred site, and which are in the best interests of the SKA as an international scientific facility.

• 3. Provide direction and oversight for a contrast and compare analysis of the site relevant data and information, existing and updated, based on the agreed scientific and technical criteria and more broadly based selection factors and utilising appropriate methods of Multiple Criteria Decision Making.

• 4. Look towards making a recommendation on a preferred site based on the scientific and technical criteria and more broadly based selection factors and the analysis of the data and information. However, if the analysis does not support a motivated recommendation, present a comprehensive report that sets out the differences between the sites based on the scientific and technical criteria and the more broadly based selection factors.

Revised (June 2010)

• 1. Establish a roadmap to site selection and manage the implementation of this roadmap up to the issuance of a report and recommendation from the SSEC on the preferred site;

• 2. Establish scientific and technical criteria and non-scientific/technical criteria and selection factors applicable to both sites to be used for identifying a preferred site, and which are in the best interests of the SKA as an international scientific facility;

• 3. Provide oversight of the site selection evaluation which is to be managed by the SSEC; concurring with a plan prepared by the SSEC for the site evaluation prior to implementation, and receiving regular progress reports and the final report and recommendation from the SSEC; and

• 4. Validate adherence to the agreed site selection process and transmit the report and recommendation on the preferred site to the SKA governing organisation for the site decision.

After an evening’s reflection, Pankonin and the ASG put two options to the SSEC: (1) the SSEC does not agree to a joint (with ASG) SSG. The SSEC would then be responsible for managing the site selection process, analysing the site characterisation data, and for making the recommendation on the preferred site. (2) The SSEC agrees to establish a joint SSG with the two objectives of establishing the roadmap for the site selection and establishing the scientific and technical criteria and more broadly-based selection factors to be used in a comparative analysis of the candidate sites. The SSEC would be responsible for analysing site data collected as part of PrepSKA WP3 activities and for making a motivated recommendation on the preferred site based on this analysis.

Not surprisingly, the SSEC accepted option 2 with an eye on the wider political picture of maintaining a positive and close relationship with the funding agencies. Revised objectives were agreed in June 2010¹³ (see Box 8.4), one consequence of which was that the SSG would not itself originate or develop solutions for preferred sites for the SKA.

It was agreed that a mutually accepted “process” would be needed to get buy-in from all collaborators in an international project. Neither the project steering committee nor an informal group of funding agencies had any line management authority over individuals/organisations in the collaborating countries. Chief among the agreed guiding principles were:

• The primary interest of the SSG was to identify the most suitable site for the SKA as an international scientific facility;

• SSG members were to adhere to principles of fairness, impartiality, transparency and freedom from governmental influence in the site selection process in carrying out their work;

• There were to be no direct communications between the SSG and the candidate host countries, except through the designated Resource Liaison persons. Requests for data and information from both candidate host countries will be made through the SPDO;

• No direct communications between individual members of the SSG and representatives of the candidate host countries were to take place on siting matters; and

• The SSG was to inform the ASG and the SSEC of progress in the conduct of its business, and when appropriate, request direction and guidance.

• The SSG would convene an independent, expert Site Selection Advisory Committee (SSAC) to review the report and recommendation from the SSEC on the preferred site to ensure that the recommendation is appropriately motivated by the data and information available. Members of the SSAC would be appointed by the SSG, with nominations from the ASG and the SSEC and giving due consideration to representation over a global geographical distribution.

• The SSG will review the report for fairness, impartiality, transparency, freedom from government influence and compliance with agreed process, and forward it to the SKA governing organisation.

8.3.4 Site Evaluation Plan

All the discussion and planning in 2009 and 2010 had to be converted into action in 2011 in order to meet the goal of having a recommendation on the preferred site by early-2012. The site selection roadmap¹⁴ set out a schedule for gathering information from the candidate sites and evaluating their responses relating to the selection factors. Initial evaluations were to be prepared by expert panels, consultants and the SPDO, and then used by the SSEC to reach a motivated recommendation on the preferred site. The recommendation would be reviewed by the SSAC to confirm that it was appropriately motivated by the available data and information before going to the SKA legal entity for the decision.

Completing these activities by early-2012 turned out to be a very tight schedule due to a number of factors. There was a large amount of material to be assembled by the sites and assimilated and analysed by the reviewing bodies. Also, there had been delays in completing the analysis of the in-situ Radio Frequency Interference (RFI) measurements, and in installing the tropospheric monitoring equipment and carrying out what was a truncated measurement campaign (see Sect. 8.4).

The main tasks for the SSG¹⁵ were: (i) to define the evaluation process, schedule, and selection factors and their weights; (ii) call for submissions from the sites; (iii) appoint expert panels and external consultants to evaluate the site responses on individual selection criteria; (iv) appoint the SSAC; (v) oversee the evaluations of the submissions by the independent experts, consultants, SPDO, SSEC and SSAC; and (vi) transmit the final recommendation to whichever formal entity was in place for the SKA in early 2012.

The main tasks for the SSEC set out in March 2011¹⁶ were to evaluate the responses from the sites, provide a comprehensive report summarising their analysis of the differences between the two sites based on the agreed criteria, and make a motivated recommendation to the SSG on a preferred site by 31 December 2011.

8.3.5 Site Selection Factors and Weights

The ASG and SSEC required that the scientific and technical selection criteria as well as the other non-scientific/technical criteria should be defined to not exclude a variety of solutions for a preferred site or sites for the SKA.¹⁷ In other words, while maintaining the vision of a single-site for the SKA, the governing bodies did not want to exclude other options, a priori.

8.3.5.1 Scientific and Technical Factors

Not surprisingly, the scientific and technical criteria mirrored those developed for the short-listing process 5 years earlier. Whereas consideration of other ‘political’ factors had been deferred in 2006, this time the other non-scientific and technical factors were specified in detail, and weights assigned after considerable discussion in the SSG. The Australian delegation to the ASG had a different view. They contended that the best way of distinguishing between the sites was to use selection factors most likely to discriminate between the sites rather than an ab-initio approach that included all potential selection factors required to enable ground-breaking science to be carried out, some of which were unlikely to be influential in making a choice because the sites were roughly equivalent. In that time of growing competition, the Australians would have considered that they would have a clear advantage in a small number of key criteria to be selected and given greater weight in the evaluation, one example being radio frequency interference. There was also the pragmatic consideration about the time required to prepare responses to all the selection factors of lesser importance.

In the end, the ab-initio approach was taken by the SSG with weights given to all relevant selection factors. But it is fair to say the details of selection factors and their weights caused heated discussion in the ASG and its successor in April 2011, the Founding Board.

8.3.5.2 Other Non-scientific and Technical Factors

Early thoughts by the SSEC¹⁸ on non-scientific and technical factors (originally called ‘indicative national attributes’) centred on topics such as

• 1. Political and economic structure and stability

• 2. Entry visas for all

• 3. Ease of government interactions

• 4. Import/export issues and taxes

• 5. Access for foreign companies

• 6. Land claims

• 7. General support of science and technology

• 8. Academic astronomy population

• 9. Availability of engineers and technical personnel

These were eventually reformulated by the SSG to the five selection factors shown in Category B in Table 8.1 below.

Table 8.1 Initial and final SSG weights for the three main selection categories

8.3.5.3 Cost Factors

Another contentious issue emerged in March 2011 after a draft version of the Request for Information had been circulated to the sites. This concerned how to evaluate the costs of locating and operating the telescope in each candidate country and whether they could be used to discriminate between the sites. The site countries contended they would not be able to generate detailed estimates for infrastructure development and operations costs in the relatively short time between the Request for Information and the deadline for submission of responses. And without the detailed information on infrastructure, it was not clear how much weight could be given to costs in the site evaluation. Complaints came from both sites about the competing demands on the site country resources as far as infrastructure was concerned, from the SPDO for relevant information affecting the telescope design being carried out in PrepSKA, and from the SSG for cost estimates. Added to this, the site countries had a legitimate grumble^19,20 that the site selection process had changed fundamentally from that originally planned in PrepSKA WP3. Site proponents were now responsible for information assembly for the Request for Information, cost estimation, and risk identification and that also put pressure on resources. Independent external consultants were originally identified for these tasks, but this was no longer affordable within the PrepSKA budget available to the SPDO.

These extra demands on resources reinforced the Australian concerns about the site selection approach. This led the Australian SSEC members, in a telephone meeting in January 2011,²¹ to suggest that the SSG timeline was not feasible given the amount of work involved and the need to engage industry to carry out some of the tasks. They again advocated that the site evaluation should carry out more risk analysis and that key discriminators between the sites be identified. By this time, the SSG had identified “cost” as one of the three main selection factors, and under the pressure from the sites felt obliged to discuss whether the cost category should be abandoned altogether.

The concept of a host country premium was discussed by the SSG in the context of potential issues during the final negotiation with the successful candidate site, but not as an explicit selection factor in the evaluation phase.

8.3.6 SKA Siting Group in Action, April 2011–January 2012

In the 10 days before the pivotal ASG-SSEC-Founding Board meetings in Rome from 29 March to 1 April 2011 (see Sect. 4.4.2), the SSG issued three crucial documents for discussion—the Request for Information from Candidate SKA Sites, Establishment of SKA Site Selection Factors and the Baseline Roadmap for SKA Site Selection. At the same time, an SSEC sub-committee comprising Schilizzi, Taylor, Terzian and Zensus issued a draft Proposal for Evaluation of the Candidate Sites for the SKA by the SSEC.²² In Rome, the SSEC approved all three SSG documents in their meeting on 29 March, but there was considerable pushback from the candidate host site countries in the separate ASG meeting that led to an existential moment for the SSG and a major change in approach to evaluation of the site proposals.

At the ASG meeting,²³ both Australia and South Africa reiterated their concerns that the additional information being requested on implementation plans and costs placed too great an additional burden, in terms of resources and effort, on the host candidate sites. The Australian delegation also returned to its contention that there were other ways to distinguish between the sites.

The Australian delegation also felt they had not had sufficient time to consider the critical SSG documents in detail since delegates had been in transit when documents were circulated. They proposed a few weeks’ delay to allow further consultation before final approval by the Founding Board. The South African delegation did not want a delay and were concerned that this could allow the host candidate sites to propose changing the weightings in their own favour. However, the ASG Chair, John Womersley, did allow a two-week delay for a review of the selection factors by the SSG after further consultation with the host candidate sites but he cautioned that it would be a concern if the selection outcome were to be finely tuned to the factor weightings. Specific instructions to the SSG were to review the selection plan with the aim of ‘refining the process’, increasing communication bandwidth, shortening the time to decision, and towards ‘making all parties broadly content’ with the process.

This approach was confirmed at the first meeting of the Founding Board on 2 April 2011. It was also noted that Pankonin had indicated he might wish to step down as Chair of the SSG given that the NSF would not be participating in the Pre-construction Phase and was not a member of the Founding Board.

Following these discussions and an ad-hoc meeting in Rome with the Site Liaison representatives, the SSG fundamentally revised its approach to the Site Evaluation Plan. After initially feeling that the ASG request to revise the approach was a vote of no confidence in the committee (which reinforced Pankonin’s view that he should step down), the SSG moved on to critically re-examine all its previous work on defining the process to select the SKA site. Three potential paths forward were contemplated: (i) make minor adjustments to the path already set out in the Roadmap and Selection Factors documents, (ii) effectively abandon the process and turn site selection over immediately to political negotiation, and (iii), the middle way, substantially revise the activities and schedules in the Roadmap, but retain the information gathering and consultant analysis and follow the Selection Factors document with some revision. The SSG opted for the third alternative, recognising that the infrastructure and cost elements could not easily be compared and so these elements should be de-coupled from the science and technical factors.

The revised plan²⁴ recognised that the Founding Board and SSEC remained the authorities to oversee, jointly, the site selection process until the end of 2011 when the Board of the new legal entity would take over this responsibility. The plan proposed substantive changes to the process addressing three principal concerns:

• 1. ensure that the process retains the integrity of a technical and defensible assessment of the qualities of the candidate sites.

• 2. streamline the process and shorten the timeline proposed in the Baseline Roadmap; and

• 3. take account of the likelihood that SKA site selection would shortly enter a phase of turbulence in which high—level political and financial aspects would play a major role as well as considerations based on quantifiable technical, scientific, and other factors.

The SSG noted views expressed by the candidate sites in letters to Womersley²⁵ that the impact of the site characteristics on science capability was under-emphasised and that the approach to identifying plans for infrastructure implementation was not structured in a way that would deliver the desired optimised plans. The SSG reaffirmed its position that the science, technical and other selection factors must be uppermost in the evaluation to underpin negotiations in the political arena, while due consideration must also be given to an assessment of how the candidate sites plan to deliver basic infrastructure and cost of delivery since these aspects were essential to any evaluation. In particular, the SSG was still concerned that the candidate sites might shape their responses towards presenting implementation plans optimised for cost rather than scientific capability.

With this in mind, the SSG recognised that the original division of selection factors was not appropriate and that these planning-based elements should be a separate category of assessment since they were to be based on the Model of the SKA (see Sect. 8.3.7 on the Request for Information), rather than primarily on measurements and factual information. The information contained in the implementation plans and costs was regarded as very important to an informed decision on the preferred site. But the SSG noted that there would be relatively greater uncertainties in the information on plans and costs than in the information for the Science and Technical factors and Other selection factors. This made it inappropriate to apply numerical comparison techniques based on weights to the plans and costs. In addition, the costs of the implementation plans at each site to the project were likely to be the subject of negotiations concerning additional host country contributions to the costs, otherwise known as “host country premiums” .

The revised weights proposed by the SSG were 75% for science and technical factors and 25% for other factors²⁶ (see Table 8.1). Implementation plans and costs were to be evaluated by external consultants in terms of their feasibility, achievability and risks, and no weights were assigned. Table 8.2 shows the detailed list of selection factors and weights²⁷ adopted by the Founding Board and SSEC.

Table 8.2 Selection factors and weights, as set by the SSG

A further recommendation by the SSG²⁸ was that an SKA Site Advisory Committee (SSAC) be charged with performing the assessment and evaluation of the data and information and with providing the motivated recommendation on a preferred site, rather than the SSEC. This was a major break with past practice established for the site short-listing in 2006 and the assumption in the intervening years.

It reflected a concern that had been growing in the SSG over the preceding months that.

it may be increasingly difficult for a stakeholder/user-­-representative group such as the SSEC to be engaged in the type of process we have initially proposed and that the current methodology places a difficult burden on SSEC members in their role of advising on the preferred site.

Put in other words, there was a concern that after so many years of interaction and consensus building on technology, science and site matters in the SSEC, it would be difficult for individual members to be completely independent in their evaluation. Removing the SSEC stage in the long line of evaluations also addressed the desire voiced by the ASG and Founding Board to reduce the time taken for the whole process, although this was not the major driver for the SSG proposal.

The SSEC did not strongly contest this development and, after South African fears had been assuaged that they were being “de-benefited”²⁹ by the attention paid to the Australian criticisms of the weighting of selection factors, the SSG revised plan was duly approved by the Founding Board and SSEC in May 2011. At the same time, the SSG mandate was reaffirmed and the Founding Board convinced Pankonin to carry on as Chair, to the good of the SKA project.

Following a careful selection process for the SSAC membership in the months that followed, a diverse group was appointed consisting of scientists, business executives, and experts on international science policy: James M. Moran, Chair, Subramaniam Ananthakrishnan, Jacob W.M. Baars, Jocelyn Bell Burnell, Willem N. Brouw, Ian Corbett, James Crocker, Thomas Garvin, Stefan Michalowski, Ernest R. Seaquist, Peter Tindemans, Jacqueline van Gorkom, and Roger J. Brissenden, Executive Secretary. Moran, Baars, Seaquist, and van Gorkum had been members of the International SKA Site Advisory Committee for the site short-listing process in 2006.

The SKA Site Advisory Committee was given its formal marching orders in its Terms of Reference (ToR).³⁰ These were to review the data and information obtained on the candidate sites, assess reports by expert panels and consultants, carry out an evaluation of the strengths and weaknesses of the sites, and formulate a recommendation on a preferred site for the SKA. The analysis and evaluation should be open to different site selection options if the data and information supported them. In keeping with the guiding principle of transparency of process, the SSAC was required to generate its own evaluation plan based on its ToR for approval by the Founding Board, SSEC, and the two sites. In particular, the SSAC was to determine the methodology for evaluating the selection factors and assessing the implementation plans and costs. The main aspects of this plan are described in Sect. 8.6.1.

8.3.7 Request for Information from the Candidate SKA Sites

The Request for Information was a major milestone in the life of the SKA project and was issued formally by the SKA Siting Group on 31 May 2011. As discussed above, in the interests of transparency, a draft had been sent earlier to Australia and South Africa for comment, and this had unforeseen consequences for the evaluation process in terms of how cost factors were approached. The Request for Information set out the schedule to site selection and the selection factors and included a Model for the SKA developed by the SPDO to serve as a benchmark for the information requested. The selection factor weights were not included as they were still under active discussion by the SSG and yet to be approved by the Founding Board and the SSEC. Approval was forthcoming a month later.

The Model of the SKA included all three receptor technologies then under consideration (dishes, low-frequency aperture arrays, and mid-frequency aperture arrays, see Fig. 8.2). A model rather than a final design was provided since the final size and scope of SKA Phase 2 was not scheduled to be decided until 2016. The Request for Information noted that despite this uncertainty, it was expected that infrastructure with similar characteristics and scale to the model of the SKA would be required for the “as-built” telescope. This included a core and the mid region out to 200 km as well as 25 stations, each containing multiple antennas of all three receptor technologies, distributed over a distance of at least 3000 km.

Fig. 8.2

Generic array configurations for SKA at distances out to 25 km from the core (left) and 180 km from the core (right). The three separate colours in the left panel represent the dish array (blue), the low-frequency aperture array (red) and the mid-frequency aperture array (green). On the expanded scale shown in the left panel, the cores for each receptor type are separated as are the “remote” receptor stations on the spiral arms. On the scale shown in the right panel, the three central arrays are superimposed on each other in the centre of the diagram, and each dot in the spiral arms marks the location of the remote stations for all three receptor types

Site-specific configurations were developed by the SPDO in conjunction with the candidate sites (see Sect. 8.4.4), but these had not been published at the time the Request for Information was released on 31 May 2011 due to delays in reaching agreement on the methodology for generation of RFI mask constraints by the candidate sites.³¹ Within a distance of 180 km from the core centre (core, inner and mid zones) they were similar to the generic configuration, but account had been taken in each Candidate Site country of specific constraints from the terrain and requirements to protect against radio frequency interference. The Request for Information noted that the site-specific configurations were to be used where required in the responses to questions.

The Request for Information noted that selection factors and broader implementation plans had been chosen that were likely to (i) differentiate between the sites, (ii) have a major impact on the cost or performance of the SKA, and (iii) could be assessed objectively.

8.3.7.1 Science and Technical Selection Factors

Information requested was:

• 1. Physical characteristics of the sites likely to affect the system design and influence the capital and operating costs, and performance of the telescope. This included (a) environmental parameters such as temperature, humidity, rainfall, wind, and solar radiation, potential hazards such as wildfires, and seismic activity, as well as restrictions due to indigenous use, ownership, or customs; (b) geotechnical information on sub-surface strata and temperatures and water table; and (c) severe weather events.

• 2. Radio Frequency Interference (RFI) environment (current and long-term) and Radio Quiet Zone (RQZ) protection. RFI measurements were carried out by site staff according to an agreed protocol using identical equipment at the same time in each array centre, and separately at four remote stations that had been chosen as examples of likely interference environments (see Sect. 8.4.2). ASTRON in The Netherlands was responsible for data analysis. For the RQZ, a report covering all aspects of its establishment including technical properties such as frequency range and allowed emission levels; timeline for RQZ establishment; applicable legislation; spectrum management regime; plans and prospects for the establishment of radio protection zones around remote stations, and spectrum usage both current and future.

• 3. Ionospheric and tropospheric characteristics. Desk studies of the ionospheric characteristics of the two sites carried out during the short-listing process in 2006 were updated. Described in Sect. 8.4.3, special purpose interferometers to monitor tropospheric opacity were acquired from the NASA Jet Propulsion Laboratory and installed at each site in 2011 after considerable delay. This meant only a truncated measurement campaign was possible before the SSAC began its evaluation.

• 4. Array science performance and associated figures of merit. A three-stage process was originally envisaged for the evaluation of the performance of an SKA located in either candidate site for typical observations to be carried out by the telescope. Stage 1 defined the ‘ideal’ or generic configuration for the SKA from image processing and other considerations. Stage 2 adjusted the generic configuration to take account of specific constraints (“masks”) for each site country and iterate using a cost model for the infrastructure to optimise the configuration in terms of Figures of Merit.³² Chief among the Figures of Merit adopted for evaluating the configurations were (1) UVGAP and PSFRMS which together measure how well the array configuration simulates a completely filled aperture whose diameter is equivalent to the largest separation of receptors in the array, and (2) Electro-Magnetic Interference risk. Stage 3 foresaw simulations by the science community being carried out using the optimised array configuration to show the proposed science case was feasible. In the end, there was insufficient time to assemble the required resources for this final stage without delaying the agreed site decision timescale, and evaluation of the performance of each array was made in terms of the Figures of Merit.

The candidate sites were expected to provide information on the physical characteristics of the sites, and on RQZ protection in item 2 in the form of separate reports. As part of PrepSKA Work Package 3 on Site Characterisation (see Sect. 4.4.1 and Sect. 8.4.2), the SPDO was to provide reports on the RFI measurements (item 2), the ionospheric and tropospheric turbulence (item 3), and the array science performance (item 4). External consultants were to contribute to reports on ionospheric scintillation (item 3), and the long-term RFI environment (item 2).

8.3.7.2 Other Selection Factors

Information requested concerned:

• 1. Political, Socio-Economic and Financial issues. The chosen site country should be characterised by a stable, mature and transparent socio-economic and financial environment to manage the expected large transactions for the SKA with minimal risk and ensure the large investment in the SKA delivers the best possible science. The candidate site had to provide an outline of the political, socio-economic and financial situation of their country and also of any other countries which had agreed to host remote stations as part of the SKA facility.

• 2. Customs and Excise. The Request for Information noted that the SKA is a global mega-science project involving scientific institutes and industry from many countries around the world, and the importance of prompt movement of goods, products and materials in and out of the Candidate Site country and countries hosting the remote stations. The sites had to supply information on the intended taxation and duty status to be afforded to the SKA organisation and its employees during the lifetime of the project as well as any import/export restrictions.

• 3. Legal issues. The Request for Information noted that the global SKA Organisation will be responsible for the construction, operation, verification and decommissioning of the SKA facility in the host country and in other countries where remote stations will be located and will be operational in multiple jurisdictions. Any legal Issues that may affect the construction and operations of the SKA in the countries that will host the core and remote SKA stations were to be described.

• 4. Security issues. Candidate sites were expected to describe their plans for achieving a secure construction and operating site and a secure near-site housing compound for the operations and maintenance staff.

• 5. Employment. Information was to be provided on issues that related to the recruitment of international and domestic staff and the resulting cost of that plan during construction and operation of SKA, as well as any relevant legislation or regulations that the SKA organisation would need to follow.

• 6. Working and support environment. The Request for Information noted that a critical element in the success of the SKA would be the attractiveness of the working and living environment for an international and well-educated staff, and availability of skilled local workforce. This included the ability of staff to find secure, good quality housing and healthcare, provision for schooling, and acceptable transport and communications links to the rest of the world. Information addressing these issues was required.

It is interesting to note that industrial support and capability was not included in the list of other selection factors despite the availability of the SPDO-developed capability survey tool mentioned in Sect. 10.9.1. The reasons for this omission are not clear.

8.3.7.3 Implementation Plans and Costs

These were requested for:

• 1. Basic infrastructure components such as roads, buildings, airstrip, dish foundations, aperture array site preparation;

• 2. Electrical power—provision for generation, transmission and distribution, rollout schedule, operations plan, capital costs, and indicative operations costs for 30 years; and

• 3. Data transport—provision of connectivity from receptors to data processor, processor to super-computer centre, and super-computer centre to data centres in other parts of the world, and capital cost of implementing and commissioning these networks as well as operational costs of running the networks both for the central area of the array and remote stations.

8.3.8 Responses to the Request for Information

Australia-New Zealand³³ (A-NZ) and Southern Africa³⁴ provided reports before the mid-September deadline on all these points apart from the RFI measurements, the ionospheric and tropospheric turbulence, and the array science performance which were the responsibility of the SPDO. External consultants contributed to the report on ionospheric scintillation, and another external consultant provided a report on expected developments in the long-term RFI environment.

The volume of paperwork delivered by the sites was substantial, 1134 pages in the case of A-NZ, and 21,328 in the case of Southern Africa. The larger volume of appendices and pages in the Southern Africa response related, in part, to the provision of comparable documentation for each of the six partner countries providing the most distant stations in the SKA Phase 2 array. A further 6346 pages of reports came from the SPDO and expert panels and consultants (see Box 8.5) for the full list of reports).

The responses and reports were reviewed by Expert Panels, external consultants (see supplementary material SKASUP8–1³⁵ for a list of people involved), and the SPDO as part of the input to the evaluation process carried out by the SSAC in the last 2 months of 2011. We describe this after an interlude to review the additional site characterisation carried out as part of PrepSKA Work Package 3.

Box 8.5 Reports Available to the SKA Site Advisory Committee, SKA Organisation Board of Directors and Members

Science and Technical Selection Factors

• 1. Ionospheric turbulence

  Report by the SPDO incorporating reports by external consultants

• 2. RFI measurement

  SPDO reports

  Review and report by Expert Panel on RFI/Electro-magnetic Interference (EMI)

• 3. Radio Quiet Zone protection

  Reports from Candidate Sites

  Review and report by Expert Panel on RQZ/Regulatory Affairs

• 4. Long term RFI environment

  Report by external consultant

• 5. Array science performance

  Report by the SPDO on the Figures of Merit for the specific configurations at each candidate site

• 6. Physical characteristics of the sites

  Reports from Candidate Sites

  Review and report by SPDO

• 7. Tropospheric turbulence

  Interim and final reports by the SPDO

  Reviews and reports by Troposphere Expert Panel

Other Selection Factors

• 8. Political, socio-­-economic and financial

  Reports by Candidate Sites

  Review and report by SSAC

• 9. Customs and Excise

  Reports by Candidate Sites

  Review and report by external consultant

• 10. Legal

  Reports by Candidate Sites

  Review and report by external consultant

• 11. Security

  Reports by Candidate Sites

  Review and report by external consultant

• 12. Employment

  Reports by Candidate Sites

  Review and report by SSEC

• 13. Working and support environment

  Reports by Candidate Sites

  Review and report by SSEC

Implementation Plans and Costs

• 14. Provision and cost of infrastructure components based on the Model of the SKA

  Reports from Candidate Sites

  Review and report by external consultant

• 15. Provision and cost of internal and external data transport based on the Model of the SKA

  Reports from Candidate Sites

  Review and report by external consultant

• 16. Provision and cost of electrical power based on the Model of the SKA

Reports from Candidate Sites

Review and report by external consultant

• 17. Consolidated costs of capital and operations expenditure

Report by SPDO

Review by SSAC

8.4 Site Characterisation

8.4.1 Expected Outcomes

During the site short-listing exercise, a certain amount of site characterisation (see Sect. 7.3.2) had been carried out at the four contending sites, primarily in-situ measurements of the RFI environment and desk-top studies of the ionospheric conditions affecting low-frequency observations. A more in-depth characterisation of the Australian and Southern African sites was an obvious element to include in PrepSKA Work Package 3. SSEC member, Jill Tarter, noted that “The RFI environment is potentially a political hot potato if we do not appear to have exercised due diligence in carrying out RFI measurements to International Telecommunication Union levels”.³⁶ This appeared relatively straightforward in prospect in 2007. But the reality was one of initially ambitious in-situ RFI and tropospheric monitoring plans being reduced in scope as delays in delivering hardware and software manifested themselves, exacerbated by a clash in priorities between the SKA site selection schedule and local precursor infrastructure construction plans.

Four expected outcomes of the PrepSKA Work package 3 were identified at the start:

• 1. (a) Statements on the current levels of RFI in the candidate countries, (b) the measures taken at government and local level to protect radio astronomy measurements with the SKA at each site, and (c) the sustainability of the sites for science on the long term in the face of potential RFI threats;

• 2. A statement on the effects of ionospheric and tropospheric turbulence on measurements with the SKA at each site;

• 3. An optimum array configuration for the SKA in each location, consistent with the science case;

• 4. Statements on the potential influences of the physical characteristics of each site on the telescope design, operations and costs, and the infrastructure deployment costs and timescales, and operational models for each site.

A Site Characterisation Working Group (SCWG) , led by SKA Site Engineer, Rob Millenaar (ASTRON, The Netherlands), was formed to coordinate the work, replacing the Site Evaluation Working Group led by Yervant Terizan. Members came from the two candidate sites, the ASTRON institute, the chairs of the SPDO Simulations and Operations Working Groups, and other experts involved in site characterisation. The SPDO Project Engineer and SKA Director were ex-officio members of the SCWG (see Box 8.6). A number of SCWG Task Forces were also formed to advise the SCWG, and the project as a whole, on RFI Monitoring, Radio Quiet Zones and Regulatory Issues, and Array Configurations.

Box 8.6 Site Characterisation Working Group

Albert-Jan Boonstra (ASTRON), Brian Boyle (CSIRO), Peter Dewdney (SPDO, ex-officio), Bernie Fanaroff (SKA SA), Rob Millenaar (chair, SPDO), Richard Schilizzi, (SPDO, ex-officio), Michelle Storey (CSIRO), Adrian Tiplady (SKA SA), Yervant Terzian (vice-chair, Cornell University).

8.4.2 Radio Frequency Interference Measurements

A detailed Memorandum of Agreement on Radio Frequency Interference (RFI) Monitoring, 2008–2011³⁷ (MoA) was signed in April 2008 by Brian Boyle (CSIRO ATNF), Bernie Fanaroff (National Research Foundation, South Africa), Michael Garrett (ASTRON, Netherlands Institute for Radio Astronomy), Richard Schilizzi (SPDO), and Philip Diamond (University of Manchester acting as legal entity representing the SPDO). The parties agreed to carry out a campaign of monitoring RFI at the two candidate SKA sites, both in the core sites and at representative remote stations, with the prime objective of informing the decision on site selection. They further agreed to accept the outcomes of the campaign as being the result of an open and fair process.

Key to the planned campaign was that measurements take place with identical hardware and control software and at the same time in the two candidate sites to ensure that solar cycle influences were the same for both locations. Carefully worded annexes were included in the MoA setting out agreed protocols for the measurement procedures, the monitoring campaign itself, instrumental and data requirements, and reporting. In 2008 when the MoA was signed, plans for MeerKAT and ASKAP were well underway and potential interference from construction activities in the core of each site was noted as a real possibility. The Measurement Plan attempted to provide a work-around for this, but delays in delivery of the hardware led to a clash of national versus international priorities that became a major limit on the success of the RFI campaign. A truncated set of measurements was all that was possible.

Another understanding among parties to the MoA was that the remote sites chosen for monitoring would be representative locations selected on the basis of reference configurations then under development by the SPDO Working Groups for the SKA in Australia and in Southern Africa. The remote sites would not be monitored to same level of sensitivity as the core sites since the former are less vulnerable to the effects of RFI. The remote locations were to be selected to allow investigation of Electro-magnetic Interference (EMI) from population centres, effects of terrain shielding and accuracy of propagation modelling for distant transmitters. There was no hint in 2008 that remote station RFI, in particular that from distant transmitters, would assume the importance it did 4 years later in the SKA Site Advisory Committee recommendation to the SKAO Board of Directors.

8.4.2.1 The RFI Campaign as Planned

Development of hardware and software was expected to last 1 year and the actual RFI monitoring and initial data analysis a further year. The measurement plan foresaw high sensitivity measurements between 80 MHz and 2 GHz to International Telecommunications Union recommended levels (ITU-R RA.769 + 15 dB)³⁸ at the core sites for about 6 months, and a similar amount of time for the remote stations. Working to RA769 levels meant the sensitivity would be up to 10,000 times better than for the 2005–6 campaign. Six months were set aside to complete of the final data analysis and report in order to meet the March 2011 deadline. The MoA was modified in May 2009³⁹ to take account of the expected increased bandwidth of the spectrometer which allowed reduced measurement time for the same sensitivity. Fifteen weeks rather than the original 6 months was assigned to the monitoring campaign at the core sites, during which time precursor construction would be halted for all but 2 weeks.

8.4.2.2 The RFI Campaign in Practice

The SPDO’s role was one of coordination and supervision without any direct authority to influence national resource allocation and timescales. The SKA Site Engineer, Rob Millenaar, coordinated execution of the Instrumentation Plan including cross-calibration of the two sets of equipment to be used at the candidate locations, the RFI measurements themselves, and he supervised the reduction and analysis of the data and production of the final report.

CSIRO ATNF was responsible for the design and assembly of a digital Fast Fourier Transform (FFT) spectrometer receiver system with which to measure the RFI environment. SKA South Africa (SKA SA) was responsible for the provision of two self-contained mobile monitoring systems to be deployed at the sites comprising radio frequency antennas and a trailer to house the electronics with its control software. Integration of the receiver system with the antennas and control software was to take place in South Africa. The design, testing and integration of these sub-systems took place on a best-efforts basis against mounting schedule pressure posed by the precursor construction deadlines, first for the MeerKAT precursor, KAT-7, in early-2010, and then delivery of the ASKAP antennas in September that same year. Despite the pressure, it is noteworthy that the collaboration to develop the RFI monitoring system remained collegial throughout.

Central to the Australian spectrometer design was a ROACH board developed by the SKA SA digital electronics team, led by Francois Kapp, as part of the CASPER collaboration (see Sect. 6.6.4.1). More than a year delay in the delivery of these boards to CSIRO had the consequence that spectrometers were delivered only in February 2010 to South Africa. A further delay of several months in South Africa was caused by the difficulty in achieving effective shielding of the trailer to reduce self-generated RFI to the levels required for the sensitive measurements of external RFI to be carried out.

The KAT-7 milestone had been passed by then, but the ASKAP deadline remained in force squeezing the time available for the RFI measurements. Postponement of the campaign until the end of the year after the ASKAP construction peak was unacceptable to the international project if the RFI results were to be available at the specified time in the site selection schedule. In the end, the simultaneous RFI campaign took place for only 4 weeks in August–September 2010, after agreement in the SSEC that the resulting reduced sensitivity to RFI was acceptable.

Remote station measurements were carried out in both countries almost a year later in mid-2011 (see Fig. 8.3) after a long period of internal discussion in South Africa on the locations for these measurements. Only 5 days of monitoring was needed per “remote” location to match the reduction in sensitivity adopted for the core location measurements.

Fig. 8.3

(Left). Rob Millenaar standing in front of the RFI measurement station at Boolardy on Wajarri Yamaji Country in Western Australia (Credit: R.P. Millenaar, ASTRON, 2008). (Right) RFI measurement station in the Karoo Desert, South Africa (Credit: R.P. Millenaar, ASTRON, 2008)

ASTRON was responsible for the software to analyse the data, a non-trivial task. As with most software, delays were inevitable and, in the end, completion of the analysis and report in 2011 was on the critical path for the site selection process as a whole (see also Box 8.7).

8.4.3 Monitoring of Tropospheric Turbulence

Radio waves passing through the Earth’s atmosphere are affected by fluctuations in the distribution of neutral gas in the troposphere—water vapour in particular—that cause three effects, refraction, absorption and scattering of the radiation (Thompson et al., 2017). These effects degrade interferometric measurements of radio sources including the quality of images and accuracy of radio source position measurements. Initially, the ISSC did not plan any direct measurements of tropospheric turbulence to investigate the sites’ suitability for high frequency astronomical observations.⁴⁰ The prevailing view was that any such measurements would be useful only if carried out for several years to obtain statistically meaningful data, and that time was not available before the site decision in 2011. In any case, removal of tropospheric effects was possible using phase referencing to nearby calibrator sources.

This changed in April 2009 when the International Engineering Advisory Committee (IEAC, see Sect. 6.2.2.3) recommended that it would be prudent to carry out direct measurements for 1 year, particularly through the summer months, for sites expected to operate at frequencies up to 20 GHz. We note that the possibility of building SKA-high on a different, higher altitude site was not under discussion at this time. The NASA Jet Propulsion Laboratory (JPL) in the US was planning to manufacture a number of interferometric tropospheric phase monitoring systems designed by Larry D’Addario for its own projects (see Fig. 8.4 (upper panel), and two SKA systems were added on (at a cost of $130 k) in February 2010. However, the expected delivery date of August 2010 did not materialise, and this meant it was no longer possible to get the desired 1 year’s worth of data, including the critical southern hemisphere summer months of December to March, before the site evaluation began in September 2011. The instrumentation arrived at the sites (see Fig. 8.4 lower left and right) in January 2011 but was not installed until March–April due, ostensibly, to lack of available local resources (see Box 8.7). Measurements at both sites were made for as long as possible before the deadline for reports to be received by the SSAC.⁴¹ This amounted to 5 months (June to October 2011).

Fig. 8.4

(upper panel) Larry D’Addario adjusting a tropospheric monitoring antenna in a test installation on the roof of the Jet Propulsion Laboratory building in Pasadena, California, USA (credit: R.P. Millenaar, SPDO, 2010). (Lower left) One of the two elements of the tropospheric phase measurement interferometer deployed in the Karoo Desert, South Africa (credit: R.P. Millenaar, SPDO, 2011). (Lower right): One of the two elements of an identical interferometer deployed at Boolardy on Wajarri Yamaji Country in Western Australia (credit: R.P. Millenaar, SPDO, 2011)

The results, such as they were, underwent analysis at the SPDO by Millenaar before evaluation by an expert panel in November and subsequently by the SSAC. However, this information had less influence than the RFI monitoring on the site recommendation by the SSAC, due to the relatively low weight (5%) given by the SSG to this selection factor.

Box 8.7 Why Did the RFI and Tropospheric Measurement Campaigns Fall behind Schedule?

Optimistic timescales for hardware design, development and testing of the RFI and tropospheric equipment and software came up against the hard deadline of SKA site selection and the hard deadlines set by the construction schedules for the national precursor telescopes, ASKAP and MeerKAT. Money was not the main issue, rather it was the collision of schedule deadlines and consequent lack of technical readiness (see Reference below).

Exacerbating the problem were resource availability and planning constraints that created considerable friction between the SPDO and the national projects during the PrepSKA era and contributed to the delays in completing the RFI and tropospheric equipment. The SPDO was aware that much was being asked of the Australian and South African teams but was frustrated that not only these groups but others in the global collaboration had not provided promised PrepSKA resources in a timely fashion for the international project.

Reference: Justin Jonas, priv. comm. to Richard Schilizzi, 26 January 2010.

8.4.4 Array Configuration Design: Buffer Zone Controversy

Developing a realistic array configuration for each candidate site was a major challenge for the SPDO and the sites and led to an existential moment for the Southern African candidature in 2010.

A Configuration Task Force (CTF),⁴² formed in 2009 and led by Millenaar, carried out simulations and optimisation of array configurations with the assistance of experts in the community. The aims were to establish configurations at each site for RFI studies as well as to carry out preliminary land acquisition studies, infrastructure planning and costing including data transport and power distribution. The strategy was to include placement constraints in the configuration software by means of “mask” information provided by the sites, and then search for allowable configurations that maximised the science capability and minimised infrastructure costs. A three-core site layout comprising dishes, dense aperture arrays and sparse aperture arrays, was adopted as the starting point (see Fig. 8.2).

The CTF generated configurations for the multiple cores, the intermediate region out to 180 km and remote stations out to 3000 km. There was at times lively debate among CTF about the array configuration of the core area for long baseline snapshot imaging and the need for redundant spacing of antennas in the core to facilitate calibration. Figures of Merit for the SKA configuration were initially discussed at a meeting of the CTF in Manchester in March 2009,⁴³ and used by the SPDO and the sites in 2010 to optimise the locations of the antennas.⁴⁴ The Figures of Merit were formally approved by the SSEC in 2011.⁴⁵ They⁴⁶ were UVGAP, EMI risk, PSFRMS (Point Spread Function Root Mean Square), sky visibility, UV coverage, and beam shape. All except EMI risk pertained to the theoretical ability of the array to perform the highest quality and most precise measurements of spectral line and continuum sources and pulsars. EMI risk was an additional Figure of Merit introduced to solve a particular problem, as we now describe.

Masks specifying “no-go” areas, or buffer zones, were generated by the sites for sources of EMI as well as geographic features following guidelines agreed by the SPDO and the candidate sites in December 2009. EMI masks indicated where levels of man-made but unintentional electromagnetic interference were too high for placing an antenna, e.g. roads, rail, and human settlements. Geographic no-go areas included bodies of water, rugged terrain, horizon limits and slopes. The EMI masks around farmsteads caused the greatest problem.

The specification adopted for farmsteads was based on CISPR⁴⁷ standards for radiated interference from devices including farm appliances and tools as well as vehicles and led to a buffer zone for acceptable levels of EMI for SKA stations of some 13.5 km in radius. This blocked out areas of the Karoo desert in South Africa to such an extent that an array configuration could not be generated for the candidate SKA site. The SKA Director came under pressure in May 2010 from some quarters to halt the site selection process on the basis that the mask issue for South Africa automatically disqualified their site, a “disabling characteristic” in site-shortlisting parlance.⁴⁸

The South African SKA Director, Bernie Fanaroff, voiced objections to the rationale and methodology followed for determining the EMI masks in emails to the Project Director and suggested an independent review addressing the South African concerns.^49,50 There was also concern in South Africa that funding for MeerKAT might dry up if the SKA site bid was disqualified.⁵¹ Following a lengthy discussion,⁵² the Executive Committee of the SSEC, on the SKA Director’s recommendation,⁵³ invited a sub-group of the Site Characterisation Working Group’s Task Force on Radio Quiet Zones and Regulatory Issues (“Review Committee”) to review the process, sources of information, standards, models and specifications used to create the EMI masks. The Review Committee comprised Wim van Driel (France, Chair), Masatoshi Ohishi (Japan) and Tom Gergely (USA), all very experienced members of the radio astronomical community specialising in these issues.

While the Review Committee was carrying out its work, the ASG decided in June 2010⁵⁴ that both candidate sites would continue into the final evaluation in 2011 and that no individual selection criterion was to be used to eliminate a site from consideration before the final evaluation. The site selection process should proceed as planned with any emerging issues considered as metrics or Figures of Merit within the process. The ASG’s decision did not obviate the need for the Review Committee’s report since it needed to be established whether the appropriate process and mask sizes had been adopted in the first place.

A Figure of Merit for EMI risk was defined⁵⁵ in such a way that it increased the closer a potential interference source, such as a farmstead, is located to an antenna. This approach allowed configurations to be designed with antennas in areas that would otherwise would have been blocked by applying the agreed EMI buffer zones around potential interference sources.

This opened the way to generate a configuration for Southern Africa.

In its report,⁵⁶ the Review Committee concluded that the procedure to determine the size of the buffer zones was generally sound and in agreement with ITU recommendations and CISPR standards. However, they pointed out that there was considerable room for interpretation and so assumptions made when creating the masks might not be valid for the SKA. They recommended further study of the CISPR standards particularly those relevant to wall attenuation and to the height of radiators used in propagation models, preferably supported by field measurements. These further studies, by the SPDO, led to a reduction of buffer zone radius from 13.5 to 10.5 km such that an antenna located less than 10.5 km from a farmstead would have a non-zero EMI risk. No field measurements were possible due to budget and time limitations.

Following the agreement on the way forward, two approaches on costing array configuration infrastructure were considered by the SSEC⁵⁷: (i) Cost a single generic configuration for both candidate sites to provide relative costings for the two sites; or (ii) Cost an optimised array for each site. The optimised array configurations were generated after the weights for the selection criteria (EMI risk, science performance, and cost) were released by the SSG, and then costed by an external consultant.

There was insufficient money available under PrepSKA WP3 to pay for two costings for each approach, and so it was decided that only the optimised (most realistic) array for each candidate sites would be costed by an external consultant. Once the optimised configurations were available, a Tiger Team would carry out simulations of performance of the optimised configurations for a small number of representative radio sources. The optimised configurations were to be ready by November or December 2010 so that the infrastructure costing could be completed by March 2011.⁵⁸

Millenaar and Rosie Bolton (University of Cambridge) visited both countries to assist local experts⁵⁹ in designing site-specific SKA Phase 2 array configurations using the generic configuration (see Sect. 8.3.7) as a starting point for the inner 180 km and using the agreed Figures of Merit (Australia, July 2010 and South Africa, September 2010)^60,61. These configurations included cores for each of the three antenna technologies and adhered to mask constraints but with the agreed, modified treatment of the EMI masks for farmhouses. The locations of the remote stations took account of the availability of land, access and possibilities for connection to infrastructure (fibre, power, roads), minimisation of impact of RFI originating from licensed transmitters (broadcasting, mobile communication), and in Australia the avoidance of severe weather systems in the north and north-west of the country.⁶² For the analysis, the maximum baselines were limited to 3000 km for both candidate sites. Additions of stations in New Zealand and further north in the African continent were not considered in the configuration design but noted as possible locations for an “extended configuration”.

Further array optimisation was expected after release of the selection factor weights (EMI risk, science performance, and cost) and costing by an external consultant. In the event, the release of the selection factor weights was delayed until May 2011, as we discuss below, which only left time for costing of the infrastructure as part of each site submission and not by an external consultant.

Figures 8.5 and 8.6 show the configurations for Australia-New Zealand (A-NZ) and Southern Africa submitted on 15 September 2011 as part of the responses to the Request for Information. In A-NZ’s case this included minor revisions compared with the July 2010 version.⁶³ These concerned relatively small changes to the locations of the remote stations to better match the expected availability of optical fibre and road connections. Both adhered to the SSG requirement in the Request for Information for baseline lengths of at least 3000 km, if only in the E-W direction (see discussion of this point in Sect. 8.6.3.1).

Fig. 8.5

The SKA array configuration proposed by Australia-New Zealand in 2011 in response to the Request for Information by the SKA Siting Group. The blue dots represent the core and mid regions of the array out to 180 km from the centre of the core, the red dots represent the locations of the remote stations provided in the A-NZ proposal. The white grid is 5 degrees on a side, corresponding to a fixed N-S length of 560 km and an E-W dimension (which varies with latitude) of 510 km along the Tropic of Capricorn (yellow line). (Credit: Fig. 6 in R. P. Millenaar, R. Bolton and J. Lazio, Array configurations for candidate SKA sites: design and analysis, 2011, report to the SSG and SSAC, hba.skao.int/SKAHB-481)

Fig. 8.6

The SKA array configuration included by Southern Africa in their proposal in 2011. The blue dots represent the core and mid regions of the array out to 180 km from the centre of the core, the red dots represent the locations of the remote stations provided in the Southern Africa proposal. The white grid is 5 degrees on a side, corresponding to a fixed N-S length of 560 km and an E-W dimension (which varies with latitude) of 510 km along the Tropic of Capricorn (yellow line). The Google map coverage in the background was incomplete at the time the diagram was prepared in 2011. (Credit: South African Radio Astronomy Observatory)

8.5 Site Selection Politics

The SKA was a sufficiently large project concept that, not surprisingly, the site competition attracted the attention of the national and local governments of the potential host countries in both the short-listing (2002–2006) and decision (2006–2012) stages.

This began in China in 1994 with senior astronomers enlisting support from the Governor of Guizhou Province where the Large Telescope would be located. This led 5 years later to initial funding from the national Ministry of Science and Technology and the Chinese Academy of Sciences for the FAST project⁶⁴ in 1999 (see Sect. 3.2.6.2). In Australia, the national government first was made aware of the SKA concept in 1996 via its participation in the OECD Mega-Science Forum (see Sect. 3.2.6.3). This was followed in 1998 by a presentation by Ekers to the Prime Minister’s Science, Engineering and Innovation Council chaired by the Prime Minister, and in the early 2000s by active involvement and funding relating to the site bid from the government of Western Australia where the central SKA site would be located. In South Africa, the national government had included astronomy as one of its priorities in the 1990s. President Thabo Mbeki voiced his support for South Africa’s bid for the SKA site in the Executive Summary of the 2005 proposal, and support also came from the Northern Cape Provincial Government, the proposed location for the SKA core (see Sect. 3.3.3.7). In Argentina, the national Secretary of State for Science and the Governor of San Juan Province where the core site for the SKA was to be located were active supporters of the 2005 site bid.

At the time of the site short-listing in 2006 and for 2 or 3 years thereafter, the entire global community expected Australia to eventually win the site competition by virtue of its excellent site credentials and its long history as a world-leading country in radio astronomy. In consequence, there was little external political activity to promote their sites on the part of Australia and South Africa. But as time went on, South Africa and Australia adopted different strategies to influence the outcome of the decision-making process while at the same time collaborating in establishing the site selection process described earlier in the Chapter, and fulfilling their responsibilities in PrepSKA Work Package 3 program on Site Characterisation.

South Africa played a low-key long game, bolstered by their confidence that they had built up a good team from the local high-tech and defence industries to design and construct the MeerKAT precursor. Their campaign aimed to turn their inexperience to an advantage by collaborating as much as possible with international SKA partners. This was led by a belief that the longer the site selection process continued before a decision was taken, the more they would benefit from increased expertise, publicity and political support nationally and internationally.

On the political side, the Heads of State and Government of the African Union adopted a Declaration at their 2010 Assembly ‘expressing the African Union’s unequivocal support for South Africa to lead the bid to locate the SKA in Africa. This Declaration also committed Africa to participate in the global SKA project, and the SKA is recognised as a flagship project by the African Ministerial Council on Science and Technology’.⁶⁵

The Australian approach to the international site politics reflected their confidence that they had the better site and better support structure for a project of the scale of SKA. This became apparent at the 2010 International SKA Forum meeting on 15 June in Assen, The Netherlands where the Ministers of Science from both Australia and South Africa were present. Presentations by the Australian speakers in the plenary session appeared to have been choreographed at government level, more in the style of a bid for the Olympic Games than for part of a scientific project. Considerable emphasis was placed on their view that an Australia-New Zealand site for the SKA would “maximise science” compared to Southern Africa. This message was at odds with the overall atmosphere of global collaboration in SKA that had been emphasised by the South African speakers at the Forum, and it engendered an adverse reaction among many in the audience.⁶⁶ It is worth noting that the Forum took place the day following the meeting of the Agencies SKA Group (ASG) where the decision had been made to allow Southern Africa to continue its bid for the site despite the geographic mask issue described earlier in Sect. 8.4.4.

Also interesting to note is that the Australia-New Zealand response to the Request for Information in September 2011 (see Sect. 8.3.8) was formally submitted by the Prime Ministers of Australia and New Zealand, Julia Gillard and John Key respectively, and the Premier of the State of Western Australia, Colin Barnett.⁶⁷ In contrast, the Southern African response was submitted by the SKA SA Director, Bernie Fanaroff, and SKA SA Alternate Resource Liaison (to the SSG), Adrian Tiplady.⁶⁸

Lobbying by both countries at top governmental levels took place in 2010 and 2011 during international summit meetings and individual visits to other countries involved in SKA. One example of the latter was the USA. Senior government officials and scientists from Australia and South Africa visited the Office of Science and Technology Policy and the State Department. Prior to visits in 2011 both these government departments requested briefs from the National Science Foundation (NSF) with regard to the NSF’s position on US involvement with SKA. If the USA were to become involved in funding for the SKA, the NSF would most likely be the cognisant funding agency. The NSF/USA maintained a neutral stance on the siting issue.

The European view was seen to be critical due to its large presence in the SKA. European Union Development Funds to help enable African countries build strong science and engineering foundations and power economic development were a source of concern for Australia as there was suspicion that support for siting SKA in Southern Africa would intensify to satisfy geo-political goals. At university level in Europe, radio astronomy programs emerged with the broad aim of promoting physics in the developing world including the African continent. Bernie Fanaroff played the “developing nations” card successfully in several talks in Europe about Southern Africa’s participation and aims in the SKA project. This led to disquiet from the Australian Government’s perspective, one example being when Fanaroff was invited to give a talk at the University of Oxford in May 2010 by Steve Rawlings, Head of Astronomy, and PrepSKA Coordinator. From the Australian perspective this appeared to be a conflict of interest and required email confirmation from the Chairs of the PrepSKA Board and the ASG that there was no need for concern.⁶⁹

8.6 Site Evaluation, Recommendation, and Final Site Decision

8.6.1 Evaluation

Despite the volume of information supplied by the sites in response to the Request for Information far exceeding expectations, the SSG decided to distribute it all to the panels and consultants, with two exceptions. These were unrequested items, a “Motivated Alternative Configuration” from Australia-NZ, and an “Acquisition Differential Cost Report 2010” from Southern Africa. The former was extensive and provided cost and implementation plans for an alternative array configuration thought suitable for the SKA in Australia (with a remote telescope station in New Zealand) and thought to cost 50% less than the Model Array included in the Request for Information. The Acquisition Differential Cost Report provided a cost comparison carried out in 2010 by a global design, engineering and advisory company, Aurecon, of the proposed scenarios for the SKA project in Australia and Southern Africa. The major differences identified, all in Southern Africa’s favour, were the power supply solutions for the remote stations and the core site, the location of the Processor Building and the extent of road upgrades and new roads required.

Following its Terms of Reference, the SSAC decided that in the interests of an equitable review both items fell outside the scope of the Request for Information^70,71 and were not considered (see Box 8.8).

Box 8.8 Site Submissions: Motivated Alternatives and Differential Costs

A fundamental principle of the SKA Siting Group’s work was that it was to oversee a fair, impartial, and transparent selection process, free from governmental influence. To have allowed the A-NZ Motivated Alternative Configuration or the Acquisition Differential Cost Report from Southern Africa would have negated the the whole Request for Information process that had been agreed by both countries after exhaustive discussion. Neither addition was made known to the SSG or the competing site country before submission of the responses in September 2011.

On configurations, the Request for Information issued by the SSG stated that ‘site-specific configurations have been developed by the SPDO in conjunction with the candidate sites, but these have not yet been published. Within a distance of 180 km (core, inner and mid zones), they are similar to the generic configuration described below, but account has been taken in each Candidate Site country of specific constraints from the terrain and requirements to protect against radio frequency interference. The site-specific configurations should be used where required in the responses to questions in the Request for Information.’ (Italics inserted by the authors of this book.) The Alternative Motivated Configuration submitted by A-NZ was not one of the “site-specific configurations developed by the SPDO in conjunction with the Candidate Sites” and had not been discussed with the SSG or SPDO before submission.

Why the A-NZ leadership followed this route is not clear. A possible factor is that the site proposal was treated in Australia as a highly confidential document and had not been discussed extensively by the broader and very experienced community before submission. It may also reflect a view in Australia that a good solution for building the SKA was more important than the process, and an expectation that if the SSAC had seen the motivated alternative they would have been independent enough to evaluate it rather than the proposal that met the formal guidelines. The thinking may have gone that, after all, the SSAC was a committee of scientific and engineering experts, not international relations diplomats. In other words, the SSAC should have made a decision based on what the countries were capable of, not just on what was included in the compliant part of the proposal.

The Acquisition Differential Cost Report appeared to be an attempt by Southern Africa to influence the evaluation by the SSAC and could not be accepted by the SSG. The report reflected the view by the South African Government that Southern Africa would have an advantage over A-NZ where infrastructure capital and operations costs were concerned, a point emphasised by Minister Naledi Pandor in her speech at the July 2011 SKA Forum meeting in Banff, Canada.

‘In this regard, I should emphasize that the SKA will only progress if cost is recognized as a critical criterion, to be fully and appropriately taken into account for all important decisions related to the further development of the project. To pretend otherwise in a global economic environment marked by austerity measures and concern regarding cost overruns at other large-scale infrastructures, will neither be a realistic, nor a responsible approach, for any funding partner.’

The expert panels, external consultants and SPDO analysed the information in the site responses in terms of strengths and weaknesses and provided written advice to the SSG which was then passed on to the SSAC. In a further step to ensure fairness, the assessments by the expert panels of the results from the RFI and tropospheric measurements were made on a “blind” basis, i.e. the country of origin of the information/data was not disclosed to the panel members. The SPDO also had an additional task of producing a report on the consolidated costs of capital and operations in which like-for-like cost estimates were assembled from the site submissions and analysed.

As set out by the SSG, the SSAC’s over-arching task was to review the almost 30,000 pages of data and information obtained on the candidate sites, assess reports by expert panels and consultants, carry out an evaluation of the strengths and weaknesses of the sites, and formulate a recommendation on a preferred site for the SKA based only on the material with which it had been provided.⁷² The analysis and evaluation was to be “open to a variety of site selection solutions, if the data and information provided to the SSAC support them”.⁷³ This point had been transferred to the SSAC from the SSG’s Terms of Reference⁷⁴ and recognised earlier discussions of a “win-win” solution in the SSEC and ASG/Founding Board.

Interactions of the SSAC with candidate site proponents, governments/government agencies, and other entities were carefully prescribed in the SSAC Terms of Reference to maintain an equitable, fair and transparent process, as had been the case in the shortlisting phase. No interactions between the SSAC and representatives of governments and/or government agencies on site-related issues for the SKA were permitted.

A non-voting Executive Secretary was appointed to facilitate the work of the SSAC while the SPDO was there to provide the technical secretariat in support of the committee’s work, and consultation, but not advice, on technical issues as required. The SPDO also acted as the communication channel between the SSAC and the candidate sites with all communications copied to the SSG. Before commencing work, the SSAC set out a rigorous evaluation process, and an equally rigorous decision-making process. Decisions by consensus was the aim but, if that was not possible, a secret vote would follow. In the event of a tied vote, it was the responsibility of the Chair to steer the SSAC to a conclusion, rather than have the casting vote.

It was a mammoth task! At the start of the final stage of the SSAC evaluation in December 2011, members interviewed the site proponents to clarify issues that had arisen in their initial analysis. Subsequently, they evaluated the information, factor by factor, in a three-step process: (i) in-depth analysis by a small sub-group yielding a preliminary score for each site or a strengths and weaknesses analysis for Category C factors, (ii) discussion by the full SSAC (see Fig. 8.7), and (iii) agreement on a final score. Each SSAC member had 20 points to distribute between the two sites for each factor, with more points indicating an advantage.

Fig. 8.7

The SKA Site Advisory Committee (SSAC) at its final meeting at Meudon Observatory in Paris in January 2012. Left to right: Wim Brouw, Tom Garvin, Peter Tindemans, Jocelyn Bell-Burnell, Stefan Michalowski, Jim Moran (Chair), Ian Corbett, Jacqueline van Gorkom, Jaap Baars, Jim Crocker, Subramaniam Ananthakrishnan, Roger Brissenden (Secretary). Not present: Ernie Seaquist. (Credit: Jaap Baars)

In three of the seventeen factors, the SSAC, using its own expertise, felt it could improve on some of the findings or conclusions of the expert reports provided. These were Factor 2, RFI Measurements where they carried out an extended desktop study of the interference caused by remote transmitters, Factor 7, Tropospheric Turbulence, where they found an error in the analysis done by the expert panel and Factor 11, Security, where the SSAC disagreed with the SSEC sub-panel’s judgement in several areas.

The SSAC did not consider any alternative solutions for the SKA project such as separate locations for the low- and mid-frequency arrays. It evaluated only the materials provided in response to the official Request for Information, and no attempt was made to suggest improvements in the proposed arrays, e.g., array configuration. Despite the somewhat ambiguous overall mandate from the SSG, the SSAC thought it was charged to make a firm recommendation on which site to choose from the two proposals, not to work out a grand compromise that made all parties happy.⁷⁵

8.6.2 SSAC Recommendation

In its report to the SSG,⁷⁶ the SSAC unanimously adopted the following consensus statement:

‘The SSAC has determined that the SKA could be sited in either Australia/New Zealand or in southern Africa. The SSAC analyzed, evaluated, and scored the 13 Technical, Science, and Other Selection Factors using the Factor weights given. The outcome was in favor of southern Africa. The SSAC also evaluated the strengths and weaknesses of the four Implementation Plans and Costs Factors. This outcome was also in favor of southern Africa. Consequently, the SSAC recommends southern Africa as the preferred site.’

The SSAC noted that two factors drove the recommendation. First, the layout of remote stations, an important consideration in Factor 5 (Array Science Performance), was constrained by the geographic and other site-specific factors in both Australia and Southern Africa. The resulting array configuration was judged to be significantly better in the Southern Africa submission giving it both higher resolution in the North–South direction and better image dynamic range for short observations. As a footnote to the earlier controversy surrounding the non-zero EMI risk caused by farmhouses in the central area of the core site in the Karoo region in South Africa (see Sect. 8.4.4), the SSAC judged that the very small increase in system temperature of individual antennas would have very little impact on the science performance. However, in reaching this decision the SSAC had not realised that the phased array transient science is far more sensitive to this EMI than the interferometric case they had considered.⁷⁷ Second, the provision and cost of 110 MW of electrical power (Factor 16) strongly favoured the Southern African proposal in the light of its existing power grid and lower generation and delivery costs.

Five of the seven Technical and Scientific Factors were judged to favour Southern Africa. In addition to array configuration, these were: the tropospheric turbulence (because of the higher elevations of the stations in the central region in South Africa), current and long-term RFI environments (based largely on the remote stations), and physical characteristics of the sites. The A-NZ site was judged to have an advantage in the Radio Quiet Zone protection Factor. With respect to ionospheric turbulence (Factor 1), which preferentially affects observations at lower frequencies, the SSAC did not find any significant difference between the sites, based on the data provided. All six of the Other Selection Factors favoured A-NZ. For the Southern Africa bid, much of the concern in these Other Factors derived from the difficulties of coordinating the laws and procedures among the six partner countries in Southern Africa, as well as the security and political challenges in the region.⁷⁸

8.6.2.1 How Robust Were these Conclusions?

The SSAC investigated the robustness of the final result to the scores for the Category A and B Factors by determining its sensitivity to a variety of tests. These included (1) censorship of data outliers; (2) a bootstrap or resampling analysis of all data; and (3) deletion of the scores of individual voting members, one at a time. In all of these tests, there was no significant variation in the result, allowing the SSAC to conclude that the final result obtained from the scores was significant and robust and not the consequence of some peculiarity of the voting procedure or voting body.

The SSG received the report on 16 February 2012, verified that the evaluation process had been carried out to its satisfaction, and transmitted the document the same day to the recently constituted SKA Organisation Board of Directors (see Sect. 4.7).

8.6.3 Final Decision

8.6.3.1 Stage 1: 16 February-3 April 2012

An earlier Board of Directors meeting in January 2012 had approved the sequence of steps leading to the final decision in a general Meeting of SKA Organisation Members, the official owners of the UK Company Limited by Guarantee. The Board became owner of the process after receiving the SSAC and SSG reports. Its first action was the formal consideration of these reports on the way to providing a commentary, including a recommended course of action, to the Members who would make the decision.

The SSAC recommendation that Southern Africa was preferred to Australia-New Zealand came as a bombshell to the members of the Board of Directors, many of whom had been involved in the project for many years. The Australia-New Zealand SKA Coordinating Committee reacted within days with a number of significant concerns with the SSAC report including the assessments for core and remote site RFI, array configuration, and implementation and cost factors.⁷⁹ There is every indication that the SSAC recommendation came as a surprise to the South Africans as well. However, they adapted quickly, and formally noted concerns that the agreed process should continue to be followed. In particular, they expressed the desire not to see the SSAC recommendation or the site selection process being unduly influenced by a potential host country. They did not question the SSAC conclusions that were not in their favour.⁸⁰ Behind the scenes, some senior South African scientists viewed the SSAC recommendation as a mandate to award their version of the SKA to Southern Africa, and that it was only fair to implement that outcome.⁸¹

A Board of Directors meeting on 22 February 2012 recognised that some of the concerns raised about the SSAC report deserved consideration to ensure the recommendation was well motivated. They resolved to invite the Chair of the SSAC to interact with the Board at its next meeting (see Fig. 8.8). Board member, Michael Garrett, noted that the SSAC report and recommendation provided an important input to the site decision but might not be the only consideration; all siting options would remain open to SKA Organisation Members to ensure the best possible outcome for the SKA.

Fig. 8.8

SSAC members Jim Moran (Chair, second from left), Roger Brissenden (second from right) and Jocelyn Bell-Burnell (right), together with Vernon Pankonin (SSG Chair) at Mr. Thomas’s Chop House, Manchester, before the SSAC presentation to the SKA Organisation Board of Directors, March 18, 2012. (Credit: Jim Moran)

In the run up to the next meeting on 19 March in Manchester (SKA-BRD-04), the Chair of the Board of Directors, John Womersley, contacted all Board members with a draft outline of a course of action to be recommended to the Members. The SKA-BRD-04 meeting turned out to be a pivotal event in the history of the SKA, and for many Board members at the time, an existential event. It was clear that the Australian delegation was preparing to fight hard to overturn the SSAC recommendation including diplomatic pressure brought to bear on SKA Organisation Member countries before the meeting. An informal meeting of Board Directors (without the Australian, New Zealand and South African representatives present) was held before the formal meeting to allow the remaining members to raise potential impediments to a consensus on the course of action. At the Board of Directors meeting itself, the Chair of the SSAC, Jim Moran, made a presentation on the SSAC’s processes and report. He also responded directly to the A-NZ concerns, clarifying the approach taken by the SSAC in reaching their conclusions on the particular selection factors at issue.⁸² In answer to a Board member’s question on why A-NZ had submitted a telescope configuration in which the North-South distribution of remote stations did not take advantage of Tasmania as the southernmost location of the array, the Australian delegate noted that neither the fibre connectivity with Tasmania nor the electro-magnetic compliance had been confirmed there until after the array configuration had been produced and submitted.⁸³

A telling comment by Moran at the end of the discussion was that, overall, only a hypothetical change in the balance of total weights between selection factor Categories A and B (see Table 8.1) from 75:25 to 66:34 would have made the vote a tie.

The Board noted that both candidate sites were well suited to host the SKA, and that the SSAC report provided a comprehensive starting point for making a site decision. Despite there being questions about the treatment of data in some areas still unresolved to the satisfaction of all parties, the Board concluded that it would not recommend to SKA Organisation Members that the SSAC re-open or re-assess the input data or restart the SSAC process altogether. Board members felt that any such actions taken in response to the concerns of only one side ran the risk of introducing bias into an otherwise independent process, and even risk the viability of the SKA project as a whole.⁸⁴

A carefully crafted Board Commentary⁸⁵ to Members, drafted by Womersley, noted four contentious issues in the SSAC report discussed in detail at the meeting but did not try to resolve them explicitly at that moment. Resolution of site selection issues was the purview of the Members rather than the Board of Directors, as set out in the SKAO Articles of Association.⁸⁶

The first of these issues, and most contentious, was the difference in conclusions reached by the SSAC and the RFI Expert Panel on the RFI environment of remote sites. The SSAC conclusions were based on their internal desktop assessment of RFI using transmitter databases⁸⁷ despite the Expert Panel report giving more weight to the in-situ RFI measurements at a sample of representative remote station locations.

The wording actually used by the Expert Panel in an addendum to their report on 19 December 2011⁸⁸ to describe their position on desk-top assessments was:

RFI predictions are only as good as the licensing database (and propagation prediction models) that go into them. Unfortunately, license databases are notoriously inaccurate, unreliable, and unsuitable for accurate predictions.

And the Panel’s conclusion was succinct:

The panel can make no meaningful conclusions about the relative suitability of the set of remote sites for the two candidate sites based on the RFI prediction studies.

These statements came with a caveat that this assessment was ‘preliminary at best’. The Panel had had very little time before the final deadline for their report to analyse the much-delayed report from the SPDO on results from additional studies by both candidate sites to attempt to predict interference levels at 25 candidate remote sites surrounding each of the two candidate core sites. The delay was caused by the late submission of relevant information from Southern Africa due to difficulties in obtaining the transmitter details in some of the countries involved.

The second issue also concerned RFI. A new analysis by the SSAC, in which the RFI results were set to be exactly equal between the two sites, showed the overall evaluation outcome still favoured Southern Africa, but with reduced significance. However, the authors of this book note that RFI is a complex phenomenon and changes rapidly with time⁸⁹ so the attempt to quantify its impact on a future SKA was fraught with difficulty.

Thirdly, while the SSAC noted the possible advantages of certain design choices suggested within the Southern African submission concerning siting of the Science Data Processor that impacted the results of the analysis of implementation and cost factors, it felt it was outside the scope of the SSAC remit to consider the feasibility of such design options in Australia.

And finally, in a similar vein, there were a number of questions about the impact of the array configuration model set out in the Request for Information, but it was not within SSAC’s remit to consider alternative configurations.

There was concern in the Board of Directors that it would be politically damaging, and a perceived waste of public investment already made, if either Australia or South Africa pulled out of the project. This led the Board to encourage the Members to consider scenarios that maximised scientific return from the investment made by both candidate sites, while also delivering what was best for the project. All Board members supported the views expressed in the commentary with the exception of the Australian delegate who abstained on instruction from the Government.

8.6.3.2 Stage 2: 4 April-24 May 2012

The SKA Organisation’s Members met for the first time on 3 April 2012 in Amsterdam 2 weeks after the Board of Directors meeting in Manchester. All but two of the Company Members sat on the Board of Directors as well (see Sect. 4.7), so they were well informed on the preceding discussions.

The final week before the Members meeting had seen a flurry of activity including internal government-level discussions in the countries participating in the SKA project and letters at the end of March from both candidate sites to John Womersley as Chair of both the Board of Directors and SKA Organisation Members. The Australia-New Zealand letter reiterated their grievances about the selection process and the SSAC recommendation and was followed by a response from South Africa a day later stating the Southern Africa standpoint again that the selection process was sound and the SSAC recommendation should stand. These letters prompted Womersley to call SKAO Members in the non-site countries to gather their views about a possible route forward before informing Australian-New Zealand and South African delegates of the direction the wind was blowing.⁹⁰

This resulted in a remarkable convergence of views on the way forward as the Members meeting unfolded.

Womersley opened the meeting with a set of comments to guide discussions on how to proceed towards the decision. Key to the direction of travel was the development of a solution that ‘built on the relative strengths of the two sites in order to maximise past investment and the potential for future investment by several highly committed governments’. To achieve this, he proposed to appoint a science-based Site Options Working Group (SOWG) to investigate the feasibility of a split-site implementation for the SKA. As Womersley recalled in 2020,⁹¹ the points made in the pre-meeting discussions were: (i) a split-site decision is largely neutral in terms of science—both sites were good with no science benefits and no negative science impacts,⁹² (ii) two sites may increase costs by 10%, (iii) a split-site decision keeps all the partners involved, hopefully bringing in more than 10% extra resources, iv) however, with a split-site decision there was real concern that the SKA might separate into independent Australian and South African telescopes, so it was important to keep the global vision of the SKA intact. European countries felt they could play a strong unifying role in this.

Such a recasting of the discussion, from a single-site to a dual site, is known in mega-project circles as “peripety” (Engwall & Westerling, 2001), a turn of events that reframes past understanding and opens a clear way forward (Smith & Winter, 2010) (see Text Box 8.9).

Box 8.9 Peripety (Crosby, 2012)

The early stages of R&D (high-tech) projects are dominated by long periods of ambiguity where solutions (and even problems) are not clear and where change is incremental. There follows a short period of peripety, where one solution (or a set of solutions) becomes the obvious candidate as the legitimate path forward. Peripety is a turn of events leading to cognitive transition from ambiguousness into a less daunting state of uncertainty, often recalled as a time when real achievement occurred. It is not simply a change of fortune, but a change of understanding of all that has gone before.

In the discussion, one of the Member representatives reiterated the point that splitting the site would fundamentally change the nature of the SKA and introduce the risk of building two telescopes that did not significantly improve, at least in Phase 1, on the performance of current interferometers. Another felt that the vision of a single-site to host the SKA should be maintained, and that the “win-win” concept did not necessarily involve only a dual-site solution, a point made several years earlier and mentioned in Sect. 8.6.1. (Note the more positive tone of the “dual-site” nomenclature compared to “split-site”. This was adopted by the SOWG when it began work). Michiel van Haarlem, Interim SKAO Director-General, emphasised that any dual-site options must be technically feasible and affordable. A decision based on a quick analysis of options could later turn out to be unaffordable which would lead to a de-scope of the project and science goals not being met. The Australian delegation supported the SOWG concept and a split-site option while the South Africans noted that the split-site option had earlier been found to have practical difficulties.⁹³ Clearly the Australian delegation was by now relieved by the proposed outcome, having realised that more support from European countries would not be forthcoming and this was the maximum that could be achieved at this stage. Majority opinion supported Womersley’s proposal for the establishment of the SOWG, and it was adopted by the Members as a formal resolution.

Site Options Working Group

SKA Organisation Members appointed SOWG members⁹⁴ (see SKASUP8–1) with a mandate to deliver their recommendations ‘in the best interests of the Project in the widest sense’ in 6 weeks’ time. SOWG Chair was Paul Alexander (UK) while Justin Jonas (South Africa) and Phil Diamond (Australia) provided their respective national perspectives within the wider SOWG mandate. Melanie Johnston-Hollitt (New Zealand), Di Li (China) Luigina Feretti (Italy) and Michael Garrett (The Netherlands) provided independent views on the SOWG deliberations. SKA Organisation Interim Director-General, Michiel van Haarlem, and Project Scientist, Joe Lazio (Jet Propulsion “Laboartory”, USA), provided the project perspective while Simon Berry (UK) was Convenor of the SOWG and functioned as its Secretary.

The SOWG met on five occasions during April and May 2012, twice face-to-face, in Manchester (UK) and Dwingeloo (NL) (see Fig. 8.9), and three times by videocon. Its task was to investigate whether viable dual-site implementation options existed for the SKA (Phases 1 and 2) and, if possible, present a preferred option. Any preferred option (or options) had to be financially viable and capable of delivering the SKA science case while making best use of the existing investments and characteristics of both sites. The SOWG was not tasked with, and did not consider, the question of whether dual-site options should be preferred to single-site implementations. Only scientific, technical, and programmatic issues, including cost and implementation risks were considered.^95,96

Fig. 8.9

The Site Options Working Group listening intently to its Chair, Paul Alexander, at its meeting in Dwingeloo, The Netherlands. Left to right: Justin Jonas, Melanie Johnston-Hollitt, Michiel van Haarlem, Paul Alexander, Simon Berry, and Phil Diamond. Not present in the photo: Luigina Feretti, Michael Garrett (photographer), Joe Lazio and Di Li. (Credit: Michael Garrett)

The starting point for the SOWG was the work done by the SSAC and earlier work and discussions about implementation options in the SSEC and ASG. The SOWG did not attempt to re-review or re-do the evaluation undertaken by the SSAC. Three options were considered in their analysis: (i) a single-site to be used as a reference for comparison, (ii) two sites split along frequency lines: e.g. locate SKA-low on one site and SKA-mid on the other, and (iii) two sites split along functional lines, in other words telescopes optimised for different science programs, notably a survey-optimised telescope and a sensitivity-optimised telescope. As their report diplomatically stated, areas of national interest were raised during discussions and noted as such in the report. Also noted were conclusions reached by majority rather than full consensus.

The first SOWG meeting in Manchester set the scene for the following weeks of intense deliberation, negotiation and compromise, with all members, and particularly the site representatives, feeling the pressure of the moment engendered by the high stakes involved. This pressure was increased for Justin Jonas when the South African Minister for Science, Naledi Pandor, paid a brief unannounced visit to the meeting to wish the participants well. Initially all options remained on the table; however there was strong opposition from the Australian representative to the idea of a complete mid-frequency/low-frequency split between Southern Africa and Australia respectively since that would mean no SKA dishes in Australia. That was unacceptable in the light of the ASKAP investment in a dish array.

By the time of the second face-to-face meeting at ASTRON in Dwingeloo, there was general acceptance that the RFI environment at the Boolardy site in Western Australia was likely to be better than in the Karoo in South Africa. This favoured Australia for the low-frequency array and became the starting point for a two-site solution. What also became clear was that the Australian “red-line” of new SKA dishes to augment ASKAP had to be observed to achieve a settlement. The SOWG attempted to take the capital and operations cost estimates for the different options of telescope construction and infrastructure including power provision and fibre links into account, but the six-week deadline for their report precluded any detailed assembly of costs versus options, or a considered assessment of them. It was however clear that the power provision for the Karoo site was not sufficient for the foreseeable future to cope with both a mid-frequency and a low-frequency instrument simultaneously.

The SOWG report,⁹⁷ submitted on 21 May 2012, put forward three main conclusions: (1) A dual-site implementation with the two sites hosting different technologies operating at different frequencies, was capable of delivering the SKA Phase 2 science case. However, there was no scientific, technical, cost or operational advantage over a single-site implementation for doing so. (2) For SKA Phase 1, distinct advantages arose from incorporating the MeerKAT and ASKAP precursors and related infrastructure into the SKA in terms of increased scientific capability and the availability to the SKA project of an estimated total investment in excess of €300 M in the precursors. (3) Additional capital costs, as well as additional operating costs and programmatic risk would result from a dual-site implementation for either SKA Phase 1 or Phase 2.

In addition to these three conclusions, the SOWG made a key proposal to overcome the concern⁹⁸ that a dual-site solution may lead to two national telescopes. This was a proposal to introduce the concept of the “SKA Observatory” , a single facility that may have multiple locations. This became a fundamental pillar for the SKA and has remained a key unifying force in subsequent years: One Observatory—Two Telescopes—Three Sites, the third being the SKAO Headquarters in the UK.

SKA Phase 2

The majority of the SOWG preferred a dual-site implementation for SKA Phase 2 that split the location of the three SKA elements on the basis of operating frequency. The SOWG thought it possible to distribute the elements—dish array, low-frequency aperture array and mid-frequency array—across the two sites without impact (positive or negative) on the science performance of the SKA. However, science delivery would be negatively impacted if any individual element was split across multiple sites. Table 8.3 shows their proposal.

Table 8.3 SOWG options for SKA Phase 2

A minority of the SOWG regarded any identification of a dual-site solution as premature.

These options for SKA Phase 2 were consistent with the detailed analysis presented in the SSAC report and, in particular, matched the mid-frequency capability to the Southern Africa site where the tropospheric stability is better. One caveat was that the mid-frequency aperture arrays were still to be evaluated as part of the Advanced Instrumentation Program, AIP, and their implementation was yet to be confirmed. A majority of the SOWG expressed a slight preference for co-locating SKA2_AIP_AA and SKA2_Mid_Dish (see Table 8.3) based on technical considerations, including the potential to cross-correlate dishes and mid-frequency aperture arrays. However, not identifying the location for the AIP component of SKA Phase 2 at this stage offered advantages in terms of risk mitigation.

A detailed assessment of the additional costs for a dual-site implementation for SKA Phase 2 could not be conducted by the SOWG in view of the six-week deadline for the report set by the Members. However, the dominant costs for each SKA element (low-frequency aperture array, mid-frequency dish array, and AIP, see Sect. 4.6.2) and the directly associated infrastructure appeared, at first sight, independent of the implementation. Retaining flexibility for the location of the AIP component offered risk mitigation advantages.

Apart from the capital investment and recurrent operating costs of power infrastructure that were substantially less for South Africa, the operation costs on the two sites were seen by the SSAC as ‘virtually the same’. In addition to the site-specific cost differential, there would be increased infrastructure costs for a dual-site implementation compared to a single-site implementation, but these additional costs, while not insignificant, were likely to be less than the overall cost uncertainty for the SKA. The operational cost of a dual-site implementation would also be somewhat higher, but this was unavoidable.

SKA Phase 1

For SKA Phase1, one of the SOWG’s prime considerations was the potential re-use of existing precursor telescopes and associated infrastructure. It was clear that the SKA Low-Frequency Array would have to be built in its entirety, with only the fibre and power reticulation infrastructure reusable on each site. No re-use of the Murchison Wide-field Array, MWA, would be possible. For the mid-frequency dish array, the science requirements for SKA Phase 1 were predicated on an array of 250x15m SKA-designed dishes (see Sect. 6.4) which could be achieved by 190 SKA dishes plus the 64x13.5 m MeerKAT dishes. This left open the possibility of deploying the remaining 60 SKA dishes from the baseline design either in South Africa as MeerKAT+250 SKA dishes, or as a ‘high speed survey instrument’ in Australia comprising ASKAP+60 wide field of view Phased Array Feed-equipped SKA dishes. The SOWG preferred the latter alternative since it would provide a more powerful survey capability than in the then current science requirements and, in particular, would better address the neutral hydrogen in absorption science driver (see Sect. 5.10.1).

The SOWG came up with options for SKA Phase 1 as shown in Table 8.4.

Table 8.4 SOWG options for SKA Phase 1

Long discussion in the SOWG was not able to resolve the question of whether the adoption of a dual-site implementation option for SKA Phase 1 implied this option was preferred for SKA Phase 2. The SOWG saw no scientific or technical reason to link SKA Phase 1 and Phase 2.

The scene was thus set for the final scenes of the SKA site selection story, the second and third meetings of the SKA Organisation’s Members on 25 May and 14 November 2012.

8.6.3.3 Stage 3: 25 May-14 November 2012

A few days prior to the meeting of Company Members on 25 May, John Womersley circulated a ‘Statement from the Chair and Proposed Actions on 25 May’ to the Members in which he laid out the options and issues confronting them. He noted that it was now time to take the decision on the site of both SKA Phase 1 and Phase 2 and concluded that ‘the most viable route for the SKA project to succeed ultimately was for Members to agree a dual-site implementation model based on the Site Options Working Group’s work’.

He noted that the SOWG had shown that ‘a scientifically justified and technically and programmatically viable approach’ to a dual-site solution was possible, and that this presented ‘the best means of optimising the use of past and ongoing investment relevant to SKA’. It also offered a model that maximised ‘the financial viability of the project in the longer term through continuation of the current Organisation membership, and a global character that will be attractive to future Members’.⁹⁹

To focus minds, he proposed the implementation given in Table 8.5 which included selection of SOWG Option A for SKA Phase 1, and co-location of aperture arrays with dishes in Southern Africa for SKA Phase 2. No further expansion of the SKA-Dish Survey Array in Australia was proposed for Phase 2.

Table 8.5 Proposed final allocation of SKA elements to candidate site countries for SKA Phase 1 and Phase 2 (reproduced with permission of the SKAO)

At the Members meeting, Paul Alexander set the context for the site selection discussion with a summary of the SOWG conclusions. Comments on this by SKAO Members generated three important clarifications underpinning the dual-site concept. The first was a confirmation that each telescope element in the baseline configuration for SKA Phase 1 would provide world-leading performance in its own right and would not simply be a prototype. The second was that delegates from both candidate sites agreed in principle with the concept of integrating their SKA precursors into the SKA Organisation. The third clarification was that both site infrastructures including the MeerKAT and ASKAP telescopes themselves would be recognised as in-kind contributions to the SKA project.

All Members were asked by Womersley to give their views on a dual-site solution as a starting point. As reported in the minutes of the meeting, the reactions of the non-site countries were mixed:

• Canada was comfortable with a dual-site solution and the SKA Observatory concept since that offered a long-term vision which would be applicable to future general science collaborations.

• China stated that the national observatory and astronomical community in China supported a single-site solution in order not to waste the work carried out since 2006 as part of the site selection process to identify a single host site. There was also concern that a dual-site implementation would increase project cost and make the SKA more complex to construct and operate.

• Italy’s preference was for a single-site solution but would consider a dual-site solution if mutually agreeable.

• The Netherlands supported the dual-site option recognising that it would potentially increase global support for the project with the associated funding that was needed to cover the additional costs associated with the dual-site solution.

• The UK supported the dual-site implementation recognising the need for re-use of infrastructure in the short-term and the importance of making progress with decisions about SKA Phase 2.

In contrast the site contenders were largely supportive:

• The Australian Government stated it was prepared to incorporate its €100 million ASKAP investment into SKA. Concerning SKA Phase 2, it proposed deferral of the decision on the location of the mid-frequency aperture array in order to mitigate technology risk. The underlying implication was that the assignment of SKA Phase 2 technology to South Africa should be contingent on its performance in SKA Phase 1.

• New Zealand favoured option A (see Table 8.4) in a dual-site implementation for SKA Phase 1.

• South Africa also supported the dual-site implementation as a means of maximising investments made at the candidate sites. However, Members were urged to make a decision about both SKA Phase 1 and Phase 2 siting at this meeting and so keep to the agreed process.

In a subsequent session from which the site country delegates (AU, NZ and South Africa) were excluded, the remaining Members discussed the caveats included in the responses above from Australia and South Africa. Womersley noted that South Africa would not accept the Australian proposal for deferral of a decision on the division of site/technology for SKA Phase 2, as that would require a further site decision in a few years’ time. As far as satisfactory performance in SKA Phase 1 as a prerequisite for assignment of a technology was concerned in Phase 2, there was general recognition that satisfactory performance in SKA Phase 1 would be a requirement for the implementation of any aspect of SKA Phase 2.

A majority of Members were in favour of a dual-site implementation based on Option A for SKA Phase 1 and an implementation for Phase 2 of the low-frequency Aperture Array in Australia, and the mid-frequency aperture array and mid-frequency dish array in Southern Africa.

When delegates from the site countries returned to the meeting, the majority view supporting the site technology choice was a bitter pill for the Australian delegation to swallow, and a long conversation with the Minister by phone was required before this was accepted, and approval was given for public release of the Members statement (see Box 8.10).

An interesting insight into how high feelings were running on both sides is that before the Members meeting in Amsterdam, Justin Jonas composed a preliminary draft of the speech to be given in South Africa by Minister of Science, Naledi Pandor, to accompany the announcement of the dual-site decision at the end of the meeting. This was based on John Womersley’s ‘Statement from the Chair and Proposed Actions on 25 May’ discussed above. The South African Department of Science and Technology (DST) rewrote the speech inserting criticism of the decision and this was distributed to journalists ahead of the speech. However, at the last minute, the Minister and Jonas rewrote the DST version restoring the diplomatic tone (see Fig. 8.10), which was delivered, to the initial confusion of the journalists.¹⁰⁰

Fig. 8.10

South African Minister of Science, Naledi Pandor, and Justin Jonas finalising the speech to be given by the Minister to coincide with the release of the press release on the site decision by the SKA Organisation’s Members on 25 May 2012 (Credit: South African Radio Astronomy Observatory)

Box 8.10 Press Release from the Members of the SKA Company on 25 May 2012

Dual site agreed for Square Kilometre Array telescope

25 May 2012, Amsterdam, the Netherlands

The Members of the SKA Organisation today agreed on a dual-site solution for the Square Kilometre Array telescope, a crucial step towards building the world’s largest and most sensitive radio telescope.

The ASKAP and MeerKAT precursor dishes will be incorporated into Phase I of the SKA which will deliver more science and will maximise on investments already made by both Australia and South Africa.

The majority of the Members were in favour of a dual-site implementation model for SKA. The Members noted the report from the SKA Site Advisory Committee that both sites were well suited to hosting the SKA and that the report provided justification for the relative advantages and disadvantages of both locations, but that they identified Southern Africa as the preferred site. The Members also received advice from the working group set up to look at dual-site options.

The majority of SKA dishes in Phase 1 will be built in South Africa, combined with MeerKAT. Further SKA dishes will be added to the ASKAP array in Australia. All the dishes and the mid frequency aperture arrays for Phase II of the SKA will be built in Southern Africa while the low-frequency aperture array antennas for Phase I and II will be built in Australia.

“This hugely important step for the project allows us to progress the design and prepare for the construction phase of the telescope. The SKA will transform our view of the Universe; with it we will see back to the moments after the Big Bang and discover previously unexplored parts of the cosmos.” says Dr. Michiel van Haarlem, Interim Director General of the SKA Organisation.

The SKA will enable astronomers to glimpse the formation and evolution of the very first stars and galaxies after the Big Bang, investigate the nature of gravity, and possibly even discover life beyond Earth.

“Today we are a stage closer to achieving our goal of building the SKA. This position was reached after very careful consideration of information gathered from extensive investigations at both candidate sites,” said Professor John Womersley, Chair of the SKA Board of Directors. “I would like to thank all those involved in the site selection process for the tremendous work they have put in to enable us to reach this point.”

Factors taken into account during the site selection process included levels of radio frequency interference, the long term sustainability of a radio quiet zone, the physical characteristics of the site, long distance data network connectivity, the operating and infrastructure costs as well as the political and working environment.

The agreement was reached by the Members of the SKA Organisation who did not bid to host the SKA (Canada, China, Italy, the Netherlands and the United Kingdom). The Office of the SKA Organisation will now lead a detailed definition period to clarify the implementation.

Scientists and engineers from around the world, together with industry partners, are participating in the SKA project which is driving technology development in antennas, data transport, software and computing, and power. The influence of the SKA project extends beyond radio astronomy. The design, construction and operation of the SKA have the potential to impact skills development, employment and economic growth in science, engineering and associated industries, not only in the host countries but in all partner countries.

The final scene of the final act was the Members meeting held on 14 Nov 2012 at which the following Resolution on SKA site selection was adopted.

The Members of the SKA Noting:

• A. The report and recommendation received from the SKA Site Advisory Committee (SSAC), dated 16 February 2012.

• B. The report on the Validation of the SKA Site Selection Process received from the SKA Siting Group (SSG), dated 16 February 2012.

• C. The report from the SKA Siting Options Working Group (SOWG) sent to the Members of the SKA Organisation on 21 May 2012

• D. The process for selecting the SKA site, laid down in the Articles of Association of the SKA Organisation.

Resolve the following:

• 1. That the SKA will be built jointly in Australia and Southern Africa (South Africa with Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia, Zambia) (collectively referred to as the host countries) in Phase 1 and Phase 2 and will incorporate the SKA Precursors ASKAP and MeerKAT and related infrastructure on those sites respectively.

• 2. That instruments based on the different types of detector technologies will be built in the host countries according to the following breakdown:

Host Country/Countries	SKA Phase 1	SKA Phase 2
Australia	SKA1_AA_low SKA1_Dish_survey	SKA2_AA_low
Southern Africa	SKA1_Dish_mid	SKA2_Dish_mid SKA2_AA_mid

AA_low: the low-frequency aperture array, Dish_survey: the dish survey instrument equipped with phased array feeds, Dish_mid: the mid frequency dish array and AA_mid: the mid frequency aperture array. The prefix SKA1 and SKA2 reflect the collecting area, baseline coverage and other technical specifications of SKA Phase 1 and Phase 2 as currently understood.

• 3. That consistent with good project management practice including validation of the implementation, cost and technological outcomes of Phase 1, satisfactory technical performance of SKA Phase 1 at both sites is expected for the implementation of the relevant SKA Phase 2 components as set out in the hosting allocation in the table above.

• 4. That all future decisions on construction depend on demonstrated progress of the design and financial viability of the construction and operational plans.

• 5. That the Members of the SKA Organisation will sign (initial) hosting agreements with Australia and South Africa as soon as possible and no later date than 31 March 2013 or a later date as decided by the Board of Directors of the SKA Organisation. These hosting agreements will as far as reasonably practicable be consistent for each site and ensure parity of treatment for each site.

• 6. The above resolutions constitute the Site Selection Decision for the purposes of Articles 44.3 and 46.1 of the Articles of Association.

8.7 Postscript

In the years since the site decision, the details of the 2012 site selection have come under scrutiny primarily as a result of more informed cost estimates for all aspects of the first phase of the project, SKA Phase 1. This has led to reductions in project scope, the major one of these being deferral of the Survey Telescope in Australia. The de-scoping exercise in 2014–5, called “re-baselining”, aimed at matching estimated costs to a “cost-cap” of €650 M and led to a reduction of the number of SKA dishes to be deployed in South Africa from 190 to 133, and a reduction in the number of SKA Phase 1-Low antenna stations in Australia each with 256 dipole antennas from 1024 to 512. This left SKA Phase 1 with a substantial margin of improvement over existing telescopes in the same frequency ranges but not the original order-of-magnitude planned. None of the 60 SKA dishes with PAFs planned as part of SKA Phase 1-Survey survived the de-scope, although they are still formally on the books as a deferred element of SKA Phase 1.

The site hosting agreements with the SKAO took 10 years to develop, far longer than thought imaginable in 2012. Along the way, there were attempts on the part of both telescope site countries to operate as independently as possible of the central SKA Organisation, raising the old fears in some quarters that two national telescopes were being created with funding from countries around the world.

In the SKA Observatory/Inter-Governmental Organisation (IGO) era (see Sect. 4.7.4) the structure and responsibilities finally agreed for the relationships with the two telescope sites are as follows: (i) each country will host an engineering operations centre and a science operations centre, and (ii) the local organisation or “site entity” will manage the telescope operations and be responsible for the required land acquisition in the core areas and land lease arrangements. In Australia this is CSIRO and in South Africa the National Research Foundation.

At the time of writing, this structure will govern the interactions of the SKA Observatory with its telescope sites in the IGO era.