Spektr-RG ( Russian: Спектр-РГ, ''

Spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...

'' + '' Röntgen'' + ''

Gamma Gamma (; uppercase , lowercase ; ) is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop . In Modern Greek, this letter normally repr ...

''; also called Spectrum-X-Gamma, SRG, SXG) is a Russian–German high-energy astrophysics space observatory which was launched on 13 July 2019. It follows on from the Spektr-R satellite telescope launched in 2011.

Background

The original idea for this X-ray observatory satellite orbiting above Earth's atmosphere, which filters X-rays, was first proposed in the 1980s by Rashid Sunyaev of the Space Research Institute of the USSR Academy of Sciences. Twenty institutions from twelve countries came together to design a large observatory with five telescopes. However, after the collapse of the

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

, the mission was abandoned due to cost-cutting from the Russian space program Roscosmos. The project was resurrected in 2003 with a scaled-down design.

Overview

The primary instrument of the mission is eROSITA, built by the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany. It is designed to conduct a seven-year X-ray survey, the first in the medium X-ray band less than 10 keV energies, and the first to map an estimated 100,000 galaxy clusters. This survey may detect new clusters of galaxies and active galactic nuclei. The second instrument, ART-XC, is a Russian high-energy X-ray telescope capable of detecting

supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...

Spacecraft

The Spektr-RG mission concept was published in 2005. Construction was finished in 2016, and by mid-2018 it was under integration and testing. It was scheduled to be launched in June 2019 but was delayed to 12 July, before the flight was postponed at the last moment. It launched the next day, 13 July 2019, from

Baikonur Baikonur ( ; ) is a city in Kazakhstan on the northern bank of the Syr Darya river. It is currently leased and administered by the Russian Federation as an enclave until 2050. It was constructed to serve the Baikonur Cosmodrome with adminis ...

Site 81/24. The observatory was integrated into a ''Navigator'' satellite bus, produced by

NPO Lavochkin NPO Lavochkin (, OKB-301, also called Lavochkin Research and Production Association or shortly Lavochkin Association, LA) is a Russian aerospace company. It is a major player in the Russian space program, being the developer and manufacturer of t ...

Mission profile and orbit

The spacecraft entered an orbit around the Sun, circling the Sun-Earth L₂ Lagrangian point in a halo orbit, about 1.5 million kilometres away from Earth. Cruise to that location took three months, during which the two telescopes were checked out and calibrated. The next four years were planned to be spent performing eight all-sky surveys. As a goal, the three years after that are planned for observations of selected galaxy clusters and AGNs ( Active Galactic Nuclei). On Monday 21 October 2019, Spektr-RG completed a 100-day cruise to L2-point. On 17 October 2019, the main eROSITA instrument achieved first light. The first light image of ART-XC was taken on July 30, 2019. The operations of eROSITA were suspended on 26 February 2022 after the Russian invasion into Ukraine upon request from Germany. At the time, eROSITA had completed four of its planned eight full-sky surveys.''Statement on the status of the eROSITA instrument aboard Spektr-RG (SRG)''
/ref> In March 2022, Russia said they turned off one of the two telescopes aboard Spektr-RG (presumably eROSITA) upon request from Germany. In June, Dmitry Rogozin, the head of Roscosmos, said he planned to unilaterally seize control of the German telescope, saying German officials' "don't have a moral right to halt this research for humankind" and that they had "pro-fascist views". However Russian astrophysicist Rashid Sunyaev said doing so could damage the instrument and would add to mistrust. In 2023 it was published that Spektr-RG found 17 new AGNs. In 2025 it was published that Spektr-RG found additional 11 new AGNs.

Instruments

Optical mission support

Russian

BTA-6 The BTA-6 () is a aperture optical telescope at the Special Astrophysical Observatory of the Russian Academy of Science, Special Astrophysical Observatory located in the Zelenchuksky District of Karachay-Cherkessia on the north side of the Cauca ...

* Caucasus Mountain Observatory * RTT-150 * Sayan Solar Observatory * International Scientific Optical Network

German

* Las Campanas Observatory * Cerro Tololo Inter-American Observatory *

Paranal Observatory Paranal Observatory is an astronomical observatory operated by the European Southern Observatory (ESO). It is located in the Atacama Desert of Northern Chile on Cerro Paranal at altitude, south of Antofagasta. By total light-collecting area, ...

* La Silla Observatory

References

External links

Official site of the project in Russia

Official site of the eROSITA telescope

Space telescope to chart first map of the Universe in high-energy X-rays
{{Orbital launches in 2019 2019 in Russia Gamma-ray telescopes Satellites of Russia Space telescopes Spacecraft launched in 2019 Spacecraft launched by Proton rockets X-ray telescopes Spacecraft using halo orbits Artificial satellites at Earth-Sun Lagrange points