Dune, the dark universe explorer mission
- Paper number
IAC-06-A3.1.06
- Author
Dr. Charles Koeck, EADS Astrium, France
- Coauthor
Mr. Sébastien Boulade, EADS Astrium, France
- Coauthor
Mr. Laurent Georges, EADS Astrium, France
- Coauthor
Dr. Alexandre Réfrégier, CEA, France
- Coauthor
Mr. Joel Michaud, Centre National d'Etudes Spatiales (CNES), France
- Year
2006
- Abstract
The CNES is currently studying the Dark UNiverse Explorer mission (DUNE), one of the promising future missions that are studied at pre-phase A level. This activity is managed by the CNES “Plateau d’Architecture des Système Orbitaux” (PASO) and is performed in cooperation with EADS-Astrium. The objective of the DUNE mission is the high accuracy measurement of the physical properties of dark matter and dark energy in the universe. These two components have been recently highlighted through measurements of the cosmic microwave background, supernovae of type Ia and large structures in local universe. The dark energy dominates the total energy density only at low redshift (z ~ 1) and raise fundamental questions on physics. To reach this target, DUNE is based on the weak lensing gravitational effect: The distribution of the dark matter in the universe is surveyed using measurements of the induced shear on background galaxies. The statistics on the shear depend on the cosmological model and can therefore be used to constrain cosmological parameters, in particular properties of dark energy. The observation of supernovae of type Ia constitutes also a secondary science objective. The deformations induced by the weak lensing effect are of the order of some percents. The weak lensing measurements are therefore very demanding in terms of image quality and systematic effects budgets. The ground observations are limited by the effect of atmosphere on the point spread function of the instrument. The DUNE project proposes to overcome these limitations with the development of a space imager with large field of view. The image quality and the size of the sky survey will provide enough accurate information to characterize the dark energy properties. A first design iteration permitted to draw a feasible and coherent mission scenario for a launch in 2010-2015, where it was demonstrated that the stringent requirements on shear measurements accuracy could be met using continuous calibration of instrument Point Spread Function (PSF) through bright stars measurements in the field of view. The present paper describes this first design of the DUNE space segment. The spacecraft is a one ton class spacecraft injected in Geostationary Earth Orbit (GEO) with a launcher of Soyuz-Fregat type. The instrument is based on a 1.2 m telescope with a 32 CCDs focal plane assembly. All system aspects are presented: science requirements, observation strategies, science data calibration, attitude and control system, orbit, launcher, propulsion, payload design, Telecommand and Telemetry system, power system and avionics.
- Abstract document
- Manuscript document
IAC-06-A3.1.06.pdf (🔒 authorized access only).
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