Cluster Technical Challenges and Scientific Achievements
The Cluster mission has been operated successfully for 14 years. As the first science mission comprising four identical spacecraft, Cluster has faced many challenges during its lifetime. Initially, during the selection process where strong competition with SOHO was almost fatal to one of them, finally both missions were merged into the Solar Terrestrial Science Programme with strong support from NASA. The next challenge came during the manufacturing process where the task to produce four spacecraft in the time usually allocated to one demanded considerable flexibility in the production process. The first launch of Ariane V was not successful, and the rocket exploded 40s after takeoff. The great challenge for the Cluster scientists was to convince ESA, the National Agencies, and the science community that Cluster should be rebuilt identical to the original one. The fast rebuilding phase, in 3 years, and the 2nd launch on two Soyuz rockets, paved the way to numerous ESA launches afterward. Finally in the operational phase, the challenge was to operate four spacecraft with the funding for one, to solve serious anomalies, and to extend the spacecraft lifetime, now seven times its initial duration with some vital elements such as batteries not working at all. After the technical challenges, the key scientific achievements will be presented. The main goal of the Cluster mission is to study in three dimensions small-scale plasma structures in key plasma regions of the Earth’s geospace environment: solar wind and bow shock, magnetopause, polar cusps, magnetotail, plasmasphere, and auroral zone. Science highlights are presented such as ripples on the bow shock, 3D current measurements and Kelvin-Helmholtz waves at the magnetopause, bifurcated current sheet in the magnetotail, and the first measurement of the electron pressure tensor near a site of magnetic reconnection. In addition, Cluster results on understanding the impact of coronal mass ejections (CME) on the Earth’s environment will be shown. Finally, how the mission solved the challenge of distributing huge quantity of data through the Cluster Science Data System (CSDS) and the Cluster Archive will be presented. Those systems were implemented to provide, for the first time for a plasma physics mission, a permanent and public archive of all the high-resolution data from all instruments.
KeywordsSun-Earth connection Magnetosphere Multi-point measurements
The authors thank the PI teams for keeping the instrument in very good shape after more than 14 years in space: K. Torkar (IWF, Austria), I. Dandouras (IRAP/CNRS, France), R. Torbert (UNH, USA), C. Carr (IC, UK), A. Fazakerley (MSSL, UK), P. Daly (Gottingen U., Germany), M. Balikhin (Sheffield, UK), M. André (IRFU, Sweden), P. Canu (LPP, France), J. Pickett (U. Iowa, USA), and J.-L. Rauch (LPC2E, France). We also thank the ESOC and JSOC teams for spacecraft and science operations as well as industry (Astrium, Germany) for their continuous spacecraft operation support. We also thank the archiving teams at ESTEC and ESAC and the CSDS teams at National data centres.
- Carr C, Brown P, Alconcel L-N, Oddy T, Fox P, Whiteside B (2013) User guide to the FGM measurements in the Cluster Active Archive (CAA), CAA-EST-UG-FGM, 2013Google Scholar
- Chapman S, Ferraro VCA (1930) A new theory of magnetic storms. Nature 126:129–130. doi:10.1038/126129a0Google Scholar
- Credland J, Schmidt R (1997) The resurrection of the cluster scientific mission. ESA Bull 91Google Scholar
- Daly P et al (2005) Users guide to the cluster science data system, DS–MPA–TN–0015Google Scholar
- Hasegawa H, Retinò A, Vaivads A, Khotyaintsev Y, André M, Nakamura TKM, Teh W-L, Sonnerup BUÖ, Schwartz SJ, Seki Y, Fujimoto M, Saito Y, Rème H, Canu P (2009) Kelvin-Helmholtz waves at the Earth’s magnetopause: multiscale development and associated reconnection. J Geophys Res 114(A12), A12207. doi:10.1029/2009JA014042CrossRefGoogle Scholar
- Henderson PD, Owen CJ, Lahiff AD, Alexeev IV, Fazakerley AN, Yin L, Walsh AP, Lucek E, Réme H (2008) The relationship between j × B and div Pe in the magnetotail plasma sheet: cluster observations. J Geophys Res 113:A07S31. doi:10.1029/2007JA012697Google Scholar
- Hwang K-J, Goldstein ML, Lee E, Pickett JS (2011) Cluster observations of multiple dipolarization fronts. J Geophys Res 116:A00I32. doi:10.1029/2010JA015742Google Scholar
- Hwang K-J, Goldstein ML, Kuznetsova MM, Wang Y, Viñas AF, Sibeck DG (2012) The first in-situ observation of Kelvin-Helmholtz waves at high-latitude magnetopause during strongly dawnward interplanetary magnetic field conditions. J Geophys Res 117, A08233. doi:10.1029/2011JA017256Google Scholar
- Laakso H, Perry C, McCaffrey S, Herment D, Allen AJ, Harvey CC, Escoubet CP, Gruenberger C, Taylor MGGT, Turner R (2010) Cluster active archive: overview, the cluster active archive. In: Laakso H et al (eds) Astrophysics and space science proceedings. Springer, Dordrecht, pp 3–37Google Scholar
- Moullard O, Burgess D, Horbury TS, Lucek EA (2006) Ripples observed on the surface of the Earth’s quasi- perpendicular bow shock. J Geophys Res 111, A09113. doi:10.1029/2005JA011594Google Scholar
- Paschmann P, Escoubet CP, Schwartz SJ, Haaland S (2005) Outer magnetospheric boundaries: cluster results. ISSI space science series. Springer. Reprinted from Space Sci Rev 118(1–4)Google Scholar
- Schmidt R et al (1990) Final report of the CSDS working group. In: ESA report CL–EST–RP–001, European Space Agency, ParisGoogle Scholar