Test facilities for VINCI®
With the replacement of the current upper-stage ESC-A of the Ariane 5 launcher by an enhanced cryogenic upper-stage, ESA’s Ariane 5 Midterm Evolution (A5-ME) program aims to raise the launcher’s payload capacity in geostationary transfer orbit from 10 to 12 tons, an increase of 20 %. Increasing the in-orbit delivery capability of the A5-ME launcher requires a versatile, high-performance, evolved cryogenic upper-stage engine suitable for delivering multiple payloads to all kinds of orbits, ranging from low earth orbit to geostationary transfer orbit with increased perigee. In order to meet these requirements the re-ignitable liquid oxygen/liquid hydrogen expander cycle engine VINCI® currently under development is designated to power the future upper stage, featuring a design performance of 180 kN of thrust and 464 s of specific impulse. Since 2010 development tests for the VINCI® engine have been conducted at the test benches P3.2 and P4.1 at DLR test site in Lampoldshausen under the ESA A5-ME program. For the VINCI® combustion chamber development the P3.2 test facility is used, which is the only European thrust chamber test facility. Originally erected for the development of the thrust chamber of the Vulcain engine, in 2003 the test facility was modified that today it is able to simulate vacuum conditions for the ignition and startup of the VINCI® combustion chamber. To maintain the test operations under vacuum conditions over an entire mission life of the VINCI® engine, including re-ignition following long and short coasting phases, between 2000 and 2005 the test facility P4.1 was completely rebuilt into a new high-altitude simulation facility. During the past two P4.1 test campaigns in 2010 and 2011 a series of important milestones were reached in the development of the VINCI® engine. In preparation for future activities within the frame of ESA’s A5-ME program DLR has already started the engineering of a stage test facility for the prospective upper stage. The new test facility P5.2 is to perform the qualification of the anticipated upper stage with the VINCI® engine. In the past year DLR has started the design phase for these modifications. The main design drivers are the test configuration and operation domain described in the test request.
KeywordsAriane 5 Midterm Evolution (A5-ME) program High-performance cryogenic upper-stage engine Re-ignitable liquid oxygen/liquid hydrogen expander cycle rocket engine Test Facilities DLR Lampoldshausen
Ariane 5 Midterm Evolution
Cahier des charges fonctionnelles—functional requirements document
Cold gas reaction control system
Equipment bay structure
Electric ground support equipment
Étage principal cryotechnique—cryogenic main stage
Étage superieur cryotechnique—cryogenic upper stage
Geostationary transfer orbit
Geostationary transfer orbit with increased perigee
Hot gas reaction control system
Inter stage skirt
Jupe avant equipée—equipped front skirt
Low earth orbit
Launch system concept review
Launch system preliminary design review
Mise au point—run-in firing test
Measurement, command and control system
Maquette remplissage—fill-in mock-up
Preliminary design review
Critical design review
Qualification (firing test)
Système de contrôle d’attitude et roulis—roll and attitude control system
Système de contrôle, d’attitude et de tassement d’ergols—control, attitude and propellant settling system
Système electrique et logiciel
To be clarified
At present and in the near future Lampoldshausen is dedicated to supporting Europe’s Ariane 5 ME program : the development of the new upper stage with the 180 kN, re-ignitable engine VINCI®. This engine is tested on the P4.1 test bed. High-altitude testing represents a major core competence in Lampoldshausen.
For risk mitigation the rocket propulsion systems have to be qualified close to the operational conditions and flight loads. The verification of the functional parameters of the operation and the performance is necessary for the prediction of the mission parameters. Special demands are imposed by the flight environmental conditions, the ground operations and the mission requirements.
With its engineering and operations departments on the one hand and the research departments on the other hand, the Institute of Space Propulsion is a unique place which delivers results from the early stages of a development project all the way to qualification of the final product: a qualified rocket engine.
In this context, the P3.2 facility for combustion chamber testing and P4.1 for high-altitude testing are presented. Furthermore, basics for the new P5.2 facility for stage testing are summarized also. A status report of the results is included.
2 VINCI® engine
Full expander cycle
High-performance LH2 and LOX turbo-pumps
Deployable composite nozzle
The nozzle is composed of a fixed part attached to the combustion chamber and a deployable part stowed around the upper part of the engine during the first stage flight. After stage separation the extendable nozzle is deployed into its operational position illustrated in Fig. 1. This allows the use of a large area ratio nozzle extension for maximum engine efficiency with minimum stage length, interstage skirt length and associated mass saving. Both the fixed and extendable nozzle sections are made from a ceramic material and supplied by Herakles.
2.1 Reference operation point
The VINCI® engine is designed to operate in a domain centered on a nominal thrust equal to 180 kN and the mixture range 5.7/5.9.
One major axis of the engine maturity demonstration program is the assessment of the re-start capability under near-vacuum condition. This function leads to place a strong focus on the igniter, the thermal control of the engine and the behavior of propellants in vacuum. The engine hot firing tests are performed at DLR P4.1 test facility. In complement to the engine testing, sub-system testing, such as full-scale combustion chamber tests, has been performed at the DLR P3.2 test facility, that just as the P4.1 test facility is located at the test site in Lampoldshausen, to carry out activities for system modeling and improvement of the design concept [3, 4].
3 VINCI® combustion chamber tests at P3.2 test facility
For detailed investigations into individual components, dynamic and thermal testing of the full-scale sub-systems has been conducted at P3.2.
In 2010 a dedicated combustion chamber test campaign has been performed to provide detailed knowledge of the regenerative cooling circuit temperatures and flow conditions as well as of wall heat fluxes and wall temperatures . The tests have been accompanied by exhaustive CFD modeling for an in-depth characterization of the hydrogen expander cycle combustion chamber.
3.1 Test bench modifications
The P3.2 is a high-pressure thrust chamber test bench that was originally erected for the development of the thrust chamber of the Vulcain engine. It was designed for providing the Vulcain thrust chamber with the necessary propellants at the required injection pressures. In the recent years the test facility P3.2 was modified to develop the thrust chamber of the VINCI® engine that uses the same propellants LH2 and LOX as the Vulcain engine. For the VINCI® engine they are supplied to the combustion chamber at about 230 bars (LH2) 80 bars (LOX), enabling test operations at more than 10 tons of thrust for up to about 60 s at the P3.2.
The propellant supply system consists of vacuum-insulated run tanks with corresponding feed lines and a pressurisation system. Volumes and pressures amount to 4.5 m³ at 350 bars for the oxygen tank and 12 m³ at 400 bars for the hydrogen tank. The vacuum-insulated feed lines to the combustion chamber in the test cell are also rated for these pressure ranges.
The required flow rate and injection pressure are achieved by pressurising these run tanks with gaseous hydrogen or gaseous nitrogen. The pressure is adjusted by a control computer. The pressurising gas is taken from high-pressure bottles each of which holds 15 m³ and can be charged up to 800 bars from the central gas supply. The propellant storage tanks are located at the test facility itself and can be directly re-filled by tanker trucks. The available capacities are 30 m³ for LH2 and 30 m³ for LOX. The run tanks are filled from these storage tanks via transfer pipes by means of low-level pressurization of the storage tanks .
The test cell of P3.2 is erected behind a solid concrete wall to protect the supply systems. The test cell accommodates the interfaces for supply lines to the combustion chamber together with the thrust stand for the horizontal installation of the combustion chamber. At the outlet a vacuum chamber, an ejector and an exhaust jet guiding system are installed. The vacuum and exhaust system are cooled with water which is supplied from a water tower located directly adjacent to the P3.2 test cell.
After completion of the modifications of the P3.2 test facility, today it is able to simulate vacuum conditions for the ignition and start-up of the VINCI® thrust chamber. The vacuum system is closed during ignition by a cover which is designed to be blown away when the start-up pressure of the thrust chamber reaches a certain level. Then an ejector keeps the conditions in the vacuum chamber at a level of about 200 mbar for the remainder of the hot fire test.
4 VINCI® engine tests at P4.1 test facility
In the M3 and M4 VINCI® engine test campaigns which took place in 2010 and 2011, for the first time tests with the new extendable composite nozzle were performed, including its complete deployment. The first hot fire testing of the complete deployed nozzle extension was successfully performed with the nozzle withstanding temperatures of more than 1,600 °C. Additionally, the VINCI® engine was re-ignited successfully under vacuum conditions subsequent to the simulation of long and short coasting phases.
to cover the operating domain with margin tests beyond the flight domain, e.g. first tests with engine throttling down to 30 kN
to operate at inlet thermodynamic conditions representative of the future upper stage, e.g. operations with sub-cooled LOX
to test design modifications of sub-systems as, e.g. fuel turbo-pump, turbine by-pass valves, thrust chamber, etc., which provide increased performance and reliability
operation at reduced thrust level (130 kN)
operation under idle mode, i.e. with out (w/o) rotation of the turbo-pumps, for de-orbitation
5 Stage tests at P5.2 test facility
For the purpose of stage level testing of the complete new upper stage (U/S) including firing stage tests with the VINCI® engine the infra-structure of the P5 test facility is designated to be extended for the erection of a new test facility, the so-called P5.2. The mission of the test bench is to ensure the development and the qualification tests of the U/S equipped with the VINCI® engine and the ground umbilical (electrical, fluidic). This section presents the necessary requirements which the test bench will have to meet to fulfill this mission. Figure 8 in the “Appendix” shows the design of the new U/S in several configurations that are dimensioned according to the type of mission: the geostationary transfer orbit (GTO) mission with and without direct de-orbiting, the low earth orbit (LEO) mission (ATV to inter stage skirt, ISS) and the GTO/geostationary transfer orbit with increased perigee (GTO+) mission.
5.1 A5-ME U/S configuration
5.2 Test scenario
performance of a MR test campaign mainly dedicated to the tank and thermal topics and integrating additional test objectives w/o hot firing
performance of M and Q test campaigns mainly dedicated to the validation and qualification of the U/S with hot firing
Configuration 1: ground and EPC flight phase
U/S including Jupe avant equipée—equipped front skirt (JAVE), ISS and cold EPC dome
Configuration 2: U/S ballistic flight (coasting) phase w/o engine firing
U/S after stage separation with nozzle extension (NE) for deployment in cold condition
U/S flight phase with engine firing
U/S after stage separation w/o NE for operating in hot-firing conditions
The baseline for the test monitoring in the MR, M and Q campaigns, at least for all test configurations in which the flight phases of the U/S are simulated, consists in using the on-board computer (OBC). Especially during the flight phases with the U/S operating in hot-firing conditions, i.e. in the M and Q campaigns, the on-board avionics shall be used to activate and control the VINCI® engine firing sequences.
5.3 Test facility configuration
sea level test bench:
1st VINCI® ignition under vacuum conditions (<60 mbar)
VINCI® re-ignitions and steady-state firing at sea level conditions
Purge lines will be under vacuum condition during engine chill-down phase (200 mbar during 30 min)
Cold gas reaction control system (CGRS) exhaust will be in vacuum condition (200 mbar for 3 h 40 min)
At sea level conditions, the thermal impact of the nozzle radiation on the U/S (e.g. heat flux input on the propellant tanks, the He vessels, etc.) is not representative with respect to the thermal status of the VINCI® engine for re-ignition at flight conditions. Instead, the nozzle radiation under vacuum will be measured during VINCI® tests at the P4.1 test facility. Thus, the stage tests at P5.2 test facility serve for the validation of the thermal model with respect to the thermal influence on stage components.
The CGRS and the Hot Gas Reaction System (HGRS) are sub-systems of the Système de contrôle, d’attitude et de tassement d’ergols, Attitude Control and Propellant Settling System (SCATE) that serves to perform the cryogenic propellant management. While for the HGRS a new green rocket propulsion system with H2O2 as monopropellant is investigated , the CGRS is derived from the existing Système de contrôle d’attitude et roulis—roll and attitude control system (SCAR) presently used for ESC-A. At the P5.2 test facility no firing testing of the HGRS is foreseen. Test objectives are limited to the thermal control concept and validation of the thermal model. The validation of the CGRS is foreseen as a passenger test during steady-state firing of the VINCI® engine. The objective is to validate the impact on the engine and on the H2 pressurization system when the CGRS is active. This test objective has a great influence on the test facility design, since an own exhaust system is required to provide vacuum conditions for the CGRS.
5.4 Test bench design
Accommodation and keeping of test items
Access, storage and handling of test items
Test items environment
Power supply, Propellant supply and management
Pressurant/conditioning/flushing fluid supply and management
Exhaust fluid management
Test run control and monitoring
Data acquisition, treatment and recording
Test safety management
Ground power provision and on-board batteries replacement
Avionics MIL 1553 bus control, avionics equipments commanding, thrust vector control
Software loading to and configuration of on-board electrical equipments
Data acquisition and archiving of standard on-board sensors
The acceptance tests of the EGSE are to be conducted at Astrium Bremen, using a mock-up of the U/S SEL for the electrical and mechanical validations during stage integration. After its successful pre-validation in the stage tests at the P5.2 test facility, potentially further use of the ESGE be made at the Ariane 5 launch pad ELA3 at the Centre Spatial Guyanais (CSG).
Cryogenic, gase and water supply from dedicated LOX/LH2 tanks and gas/water storage capacities at P5
Central Measurement, Command and Control (MCC) system located at P5 control room and its associated systems (cabling, main computer, …)
5.5 Test operation domain
The P5.2 test facility has to cover the whole operation domain of the A5-ME U/S. In order to provide the aspired versatility of A5-ME its U/S shall be capable to deliver payloads not only in GTO but also in GTO+. Therefore, the stage’s operation domain is divided into the GTO flight domain and the GTO extreme domain. In order to provide the mission flexibility for delivering multiple payloads to all kinds of orbits the thrust of the VINCI® engine must be adjustable over a wide range. Therefore, the VINCI® shall be operated at 100 % thrust (180 kN) and in a reduced thrust domain (see Table 3).
In order to optimize the performance of the U/S with respect to de-orbitation the operation of the VINCI® engine under idle mode is under investigation, extending the operation domain that needs to be covered by the test facility, to the lowest possible margin.
5.6 Test bench requirements
General requirements, e.g. bench geometry, test rig, test sequence and duration, fluid storages, etc.
Operational requirements, e.g. availability, test frequency, reduced thrust, etc.
Interface requirements, e.g. mechanical, fluid and electrical interfaces
Hardware environment, e.g. atmospheric, thermal and electromagnetic environment, vacuum simulation, etc.
Adjacent structures, e.g. the EPC LOX bulkhead
Control and measurements, e.g. transducer type, number of measurement chains, sampling rate, acquisition system, etc.
to fill and to degas the LOX tank and the LH2 tank
to pressurize both propellant tanks with ground helium
to evacuate the engine fluids during chill down and to evacuate the tank degassing
to manage tank pressure in case on coupling plate failure or emergency deloading
Filling of the LOX tank
Criteria of filling
Filling temperature range (K)
T < 92
Filling pressure range (bar)
1 < P < 5
Filling mass flow range (l/s)
0.5 < Q < 6.0a
Filling of the LH2 tank
Criteria of filling
Filling temperature range (K)
20 < T < 21
Filling pressure range (bar)
1 < P < 5
Filling mass flow range (l/s)
1 < Q < 15a
The bench shall control the interface pressure during the phases of loading (at an accuracy of ±0.2 bar) and also the interface temperature, which will have to be maintained during the loading in a range of ±0.5 K on the LOX and ±0.2 K on the LH2 side, respectively.
Further fluid interfaces have to be provided for the HGRS and for the CGRS of the SCATE as well as for the umbilical to the EBS and the EPC dome. For the installation validation of the test facility different mock-ups of certain stage components will be used. The DLR will build wooden mock-ups of the structures bearing the mechanical and fluid interfaces.
The bench’s compatibility to the requested reduced thrust domain from 50 to 200 kN is presently being investigated in a dedicated DLR study to decide about the use and the design of a supersonic diffuser (SSD). Thus, the performance of the P5.2 test bench with respect to the engine operating domain tested in the M and Q campaigns is yet to be clarified (TBC). On the other hand, regarding its performance with respect to the control and measurement capabilities, Table 4 in the “Appendix” gives a first overview of the amount of channels needed for the M/Q campaigns, even so their type, number and sampling rate might evolve during the U/S development. The measurements were counted taking into account forecasts from stage and engine equipment.
6 Summary, conclusion and outlook
All requirements for the erection of the P5.2 test facility were cleared to proceed with the critical design review (CDR) phase. The CDR will be completed by summer 2013 to assure the availability of the bench in 2015.
The P5 and the P5.2 will have major equipments in common (MCC, LOX and LH2 tanks, etc.). The operations on these two benches will have to be diligently managed to avoid unexpected interactions from a bench towards the other. Concerning the P5 MCC specific tools have to be developed to check the status of the test bench after a configuration change (P5 → P5.2 or P5.2 → P5).
The authors would like to thank Mr. Rüdeger Albat, ESA A5-ME Project Manager, and Pier Michele Roviera, ESA A5-ME Ground Segment Manager, for their kindly contribution to the realization of this paper by means of granting access to the P5.2 Functional Requirement Document and PDR Report and providing the approval to use parts of them inside this paper.
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