The scientific spacecraft “Spectrum-Roentgen-Gamma” (Spectr-RG or SRG) is an X-ray observatory. SRG’s main scientific goal is to chart an unprecedented map of the Universe in X-rays on which all large clusters of galaxies will be marked.
Mapping the large-scale structure of the Universe is much like a time travel into the past. This map will be essential to solve the core questions of modern cosmology: How do dark energy and dark matter affect formation of the large-scale structure of the Universe? What is cosmological evolution of supermassive black holes? Spektr-RG is expected to find about 100,000 massive clusters of galaxies during the four-year survey mode, which means literally all such objects in the observable Universe. Furthermore, it will detect around three million supermassive black holes in active galactic nuclei (AGN), along with hundreds of thousands of stars with active coronae and accreting white dwarfs, tens of thousands of galaxies with active star formation. There might even be other objects of unknown nature. Spektr-RG will also study the hot interstellar and intergalactic medium, which is a source of bright X-ray emission.
The Spektr-RG astrophysical space observatory is developed by the Russian side under the Federal Space Program of Russia, section on Fundamental Space Research, by order of the Russian Academy of Sciences with the participation of Germany. The SGR platform was constructed by the NPO Lavochkin.
The main scientific goals of «Spectr-RG»
- The first all-sky survey with an imaging telescope in the 0.5-11 keV band and the first all-sky imaging X-ray time variability survey.
- Follow-up pointed observations of selected sources with high sensitivity in 3-axis stabilized regime in up to 30 keV energy range.
|2||Launch site||Baikonur 81, Kazakhstan|
|3||Launcher||Proton-M launch vehicle with Upper Stage DM-03|
|4||Reference system||the second Lagrange point (L2) of the Sun-Earth system.|
|5||Expected lifetime||6,5 year|
|6||Spacecraft wet mass||2712,5 kg|
|7||Scientific payload mass||1210 kg|
|8||RF line band
|9||Science data transmission rate||512 Kbit/s|
|10||Science equipment power||1805 W|
The scientific payload consists of two independent telescopes — a soft-X-ray survey instrument, eROSITA, being provided by Germany, and a medium-X-ray-energy survey instrument, ART-XC (Astronomical Roentgen Telescope- X-ray Concentrator), being developed by Russia. Both exploit the principles of grazing incidence imaging X-ray optic. To be reflected, X-ray photons must hit the mirror surface at a very small angle. Hence, X-ray mirrors are very oblong and tube-like. To increase the number of photons registered, several mirrors of ever increasing diameters are nested one into the other. Thus, one module consists of several mirror shells, and both telescopes consist of 7 modules each, with high-performance X-ray detectors placed in each focal point. The SGR spacecraft is based on the “Navigator” multi-use bus adapted for the tasks of the project. Navigator platform is developed as the baseline module for key systems adaptable for various payloads and orbits. Navigator is a flight qualified platform. The Spektr-R highly elliptical spacecraft (launched in 2011) and two hydrometeorological Elektro-L geostationary satellites (launched in 2011, 2015) were built on this platform. This platform is developed by the NPO Lavochkin Scientific Production Association (Russia).
- ~3 months flight to L2 will be used in the verification and calibration of the payload.
- 4 years – duration of an all sky survey 0.3-11 keV energy band; 8 all sky surveys (scanning mode: 6 rotations/day, 1 degree advance per day)
- 2,5 years — follow-up pointed observations of selected objects and regions in the harder X-ray range up to30 keV in a 3-axis stabilization mode.
- State Space Corporation «ROSCOSMOS» (ROSCOSMOS)
- The German Aerospace Center (DLR) (Deutsches Zentrum für Luft- und Raumfahrt e.V.,DLR)
- Lavochkin Scientific and Production Association (NPO Lavochkin)
- Space Research Institute Space Research Institute (IKI RAS)
- The Max Planck Institute for Extraterrestrial Physics (Max Planck Institut fuer Extraterrestrische Physik, MPE)
- Russian Federal Nuclear Center — All-Russian Research Institute of Experimental Physics , Sarov (FSUE RFNC – VNIIEF)
- NASA Marshall Space Flight Center, USA (MSFC), see also ART-XC page.
- Institute for Astronomy and Astrophysics (IAAT), University of Tuebingen
- Hamburg Observatory, Hamburg University
- Leibniz Institute for Astrophysics Potsdam (AIP)
- Dr. Remeis Observatory Bamberg, University Erlangen-Nuremberg
- from the Russian side for scientific payload: IKI RAS
- from the Russian side for space and ground segment (except for scientific payload): Lavochkin Association
- from the German side for eROSITA telescope: MPE
- Mission Scientific Leader from the Russian side: Acad. Rashid Sunyae
- eROSITA telescope Principal Investigator from the German side: Dr. Peter Predehl