Spectrum-RG/eROSITA/Lobster astrophysical mission

A medium size satellite will be launched in the 2010-2011 timeframe into a 600 km equatorial (less than or equal to 5 deg.) orbit from Kourou or into a less than or equal to 30 deg. orbit from Baikonur as a fallback option. The payload includes eROSITA (extended ROentgen Survey with an Imaging Telescope Array, MPE, Germany) with 7 Wolter-type telescopes, the wide field X-ray monitor Lobster (LU, UK), the X-ray concentrator based on Kumakhov optics ART or coded-mask X-ray telescopes as a fallback (IKI, Russia; GRB detector (Russian consortium). High particle background on high apogee orbits severely affects the capabilities of X-ray telescopes to study diffuse emission. For new baseline configuration of the SRG mission a low earth orbit was selected to circumvent this limitation. The mission will conduct the first all-sky survey with an imaging telescope in the 2-12 keV band to discover the hidden population of several hundred thousand obscured supermassive black holes and the first all-sky imaging X-ray time variability survey. In addition to the all-sky surveys it is foreseen to observe the extragalactic sky with high sensitivity to detect 50 to 100 thousand clusters of galaxies and thereafter to do follow-up pointed observations of selected sources, in order to investigate the nature of Dark Matter and Dark Energy. The new SRG mission would thus be a highly significant scientific and technological step beyond Chandra/XMM-Newton and would provide important and timely inputs for the next generation of giant X-ray observatories like XEUS/Con-X planned for the 2015-2025 horizon.