ESA/SRE(2011)12 July 2011 Euclid Mapping the geometry of the dark Universe Definition Study Report European Space Agency 1 Euclid Mapping the geometry of the dark Universe Definition Study Report ESA/SRE(2011)12 July 2011 September 2011 (Revision 1) 2 On the front cover: composite of a fragment from Raphael’s fresco “The School of Athens” in the Stanza della Segnatura of the Vatican Palace depicting the Greek mathematician Euclid of Alexandria, a simulation of the cosmic web by Springel et al, and an image of Abell 1689; the composition is made by Remy van Haarlem (ESA/ESTEC). 3 Euclid Mission Summary Main Scientific Objectives Understand the nature of Dark Energy and Dark Matter by: Reach a dark energy FoM > 400 using only weak lensing and galaxy clustering; this roughly corresponds to 1 sigma errors on wp and wa of 0.02 and 0.1, respectively. Measure γ, the exponent of the growth factor, with a 1 sigma precision of < 0.02, sufficient to distinguish General Relativity and a wide range of modified-gravity theories Test the Cold Dark Matter paradigm for hierarchical structure formation, and measure the sum of the neutrino masses with a 1 sigma precision better than 0.03eV. Constrain ns, the spectral index of primordial power spectrum, to percent accuracy when combined with Planck, and to probe inflation models by measuring the non-Gaussianity of initial conditions parameterised by fNL to a 1 sigma precision of ~2. SURVEYS Area (deg2) Description Wide Survey 15,000 (required) Step and stare with 4 dither pointings per step. 20,000 (goal) Deep Survey 40 In at least 2 patches of > 10 deg2 2 magnitudes deeper than wide survey PAYLOAD Telescope 1.2 m Korsch, 3 mirror anastigmat, f=24.5 m Instrument VIS NISP Field-of-View 0.787×0.709 deg2 0.763×0.722 deg2 Capability Visual Imaging NIR Imaging Photometry NIR Spectroscopy Wavelength range 550– 900 nm Y (920- J (1146-1372 H (1372- 1100-2000 nm 1146nm), nm) 2000nm) Sensitivity 24.5 mag 24 mag 24 mag 24 mag 3 10-16 erg cm-2 s-1 10σ extended source 5σ point 5σ point 5σ point 3.5σ unresolved line source source source flux Detector 36 arrays 16 arrays Technology 4k×4k CCD 2k×2k NIR sensitive HgCdTe detectors Pixel Size 0.1 arcsec 0.3 arcsec 0.3 arcsec Spectral resolution R=250 SPACECRAFT Launcher Soyuz ST-2.1 B from Kourou Orbit Large Sun-Earth Lagrange point 2 (SEL2), free insertion orbit Pointing 25 mas relative pointing error over one dither duration 30 arcsec absolute pointing error Observation mode Step and stare, 4 dither frames per field, VIS and NISP common FoV = 0.54 deg2 Lifetime 7 years Operations 4 hours per day contact, more than one ground station to cope with seasonal visibility variations; Communications maximum science data rate of 850 Gbit/day downlink in K band (26GHz), steerable HGA Budgets and Performance Mass (kg) Nominal Power (W) industry TAS Astrium TAS Astrium Payload Module 897 696 410 496 Service Module 786 835 647 692 Propellant 148 232 Adapter mass/ Harness and PDCU losses power 70 90 65 108 Total (including margin) 2160 1368 1690 4 Foreword Euclid is a Medium Class mission of the ESA Cosmic Vision 2015-2025 programme, and competes for one of the two foreseen launch slots in 2017 and 2018. This report (the Euclid Red Book) describes the outcome of the Phase A study, which started with the industrial kick-off in July 2010 and ended with the completion of the Preliminary Requirement Review in July 2011. Phase A is the first part of the Mission Definition Phase in which the mission is prepared for the Implementation Phase where an industrial prime contractor will lead the system development and the Euclid Mission Consortium will provide elements of payload and science ground segment. The Assessment Phase of Euclid, which preceded Phase A, showed that the Euclid science and mission concept are feasible and could meet the M Class mission requirements. However, the study also showed that a serious optimisation of the mission was necessary to stay within the programmatic constraints with sufficient margin. In particular, the payload mass had to be reduced to create margin for a Soyuz launcher, and a lower number of detectors was recommended, since procurement of many detectors has a high schedule risk beyond the foreseen launch in 2018. The Euclid study team considered several options to optimise the mission, but only a few cases could be investigated in detail. The most viable solution was the merging of the near-infrared photometric and spectroscopic channels into one instrument with a single focal plane array and with a reduced number of near-infrared detectors. This concept provides a comfortable system mass margin due to a payload mass reduction as a result of a more compact payload design. The optimisation comes with a price: the near- infrared spectroscopic and photometric observations are now done sequentially instead of simultaneously, thereby significantly increasing the observation time for a single field. A team of 6 scientists, the Euclid Optimisation Advisory Team (EOAT), was selected to provide re- commendations on the set of mission parameters that can meet the Euclid science objectives and top level requirements, taking into account the optimised payload. It was decided that a payload configuration with 16 NIR detectors for NISP, would best meet the Euclid science requirements. The alternative configuration with a smaller FoV and consequently fewer detectors was rejected as baseline because of its inability to meet the sufficient survey area during the nominal mission. The new payload and mission concept was used to prepare the invitation to tender (ITT) for two competing Definition Phase studies by two independent industrial consortia. Two industrial contractors were selected: Thales Alenia Space Italy (Turin) and Astrium GmbH Germany (Friedrichshafen). Both industrial teams already performed the Assessment Phase studies, and carry a lot of expertise about the Euclid mission. In June 2010 the Euclid Science Management Plan was accepted by the Science Programme Committee. The science management plan provides the programmatic framework for the issue of the Euclid Announcement of Opportunity for a single consortium - the Euclid Mission Consortium - to provide elements of the payload and the science ground segment. A European wide consortium consisting of 7 lead countries submitted their proposal in October 2010 and was selected by the Science Programme Committee in February 2011. The Euclid Science Management Plan was updated in June 2011 and reflects the latest programmatic developments as well as the data release scheme for Euclid. This report provides a description of the Euclid mission as emerged from the phase A study. Section 1 gives the executive summary. The science case is provided in Section 2. The first level science requirements and the top level instrument and mission requirements are provided in Section 3. Payload and mission are described in Sections 4 and 5, respectively. An assessment of the system and instruments performance in view of the science requirements is provided in Section 6. The description of the ground segment is given in Section 7, and the management and programmatics are described in Section 8. The Euclid Study Team, July 2011 5 Authorship and Acknowledgements Euclid Red Book Editorial Team R. Laureijs ESA/ESTEC, The Netherlands (Chair; ESA Study Team) J. Amiaux CEA /IRFU Saclay, France S. Arduini IAP UPMC Paris, France J.-L. Auguères CEA/IRFU Saclay, France J. Brinchmann Leiden Univ., The Netherlands R. Cole UCL-MSSL, London, UK M. Cropper UCL-MSSL, London, UK (ECB, EST member)) C. Dabin CNES, Toulouse, France L. Duvet ESA/ESTEC, The Netherlands (ESA Study Team) A. Ealet CPPM and LAM, Marseille, France B. Garilli INAF IASFMI, Milan, Italy P. Gondoin ESA/ESTEC, The Netherlands (ESA Study Team) L. Guzzo INAF OA Brera, Italy J. Hoar ESA/ESAC, Spain (ESA Study Team) H. Hoekstra Leiden Univ., The Netherlands R. Holmes MPIA, Heidelberg, Germany T. Kitching ROE, Edinburgh, UK T. Maciaszek CNES, Toulouse, France Y. Mellier IAP UPMC, Paris, France (ECL) F. Pasian INAF OA Trieste, Italy W. Percival Univ. Portsmouth, UK J. Rhodes JPL, Pasadena CA, USA (ECB) G. Saavedra Criado ESA/ESTEC, The Netherlands (ESA Study Team) M. Sauvage CEA/IRFU Saclay, France R. Scaramella INAF OA Roma, Italy (ECB) L. Valenziano INAF IASFBO Bologna, Italy S. Warren Imperial College London, UK ESA Study Team L. Duvet Study Payload Manager P. Gondoin Study Manager J. Hoar Science Operations R. Laureijs Study Scientist G. Saavedra Criado System Engineer Euclid Consortium Board (ECB) R. Bender MPE Garching and USM Muenchen, Germany F. Castander IEEC Barcelona, Spain (EST member) A. Cimatti Univ. of Bologna, Italy (EST member) M. Cropper UCL-MSSL London, UK (EST member) O. Le Fèvre LAM Marseille, France H. Kurki-Suonio Univ. Helsinki, Finland M. Levi LBL Berkeley CA, USA P. Lilje ITA Univ. Oslo, Norway Y. Mellier IAP UMPC Paris, France (ECL) G. Meylan EPFL Lausanne, Switzerland R. Nichol Univ. Portsmouth, UK K. Pedersen SSC Univ. Copenhagen, Denmark V. Popa ISS Bucharest, Romania R. Rebolo Lopez IAC, Spain J. Rhodes JPL, Pasadena CA, USA H.-W. Rix MPIA, Heidelberg, Germany (EST member) H. Rottgering Leiden Univ, The Netherlands R. Scaramella INAF OA Roma, Italy W. Zeilinger IfA Univ. Wien, Austria 6 Other Euclid Tiger Team (TT) contributors (not in previous lists) F. Grupp MPE Garching and USM Muenchen, Germany P. Hudelot IAP UPMC, France R. Massey ROE Edinburgh, UK M. Meneghetti INAF OA Bologna, Italy L. Miller Oxford Univ., UK S. Paltani Univ. Genève, Switzerland S. Paulin-Henriksson CEA/IRFU Saclay, France S. Pires CEA/IRFU Saclay, France C. Saxton UCL-MSSL London, UK T.