On July 13, 2019, a landmark launch for the national cosmonautics took place from the Baikonur cosmodrome. The unique orbital observatory “Spektr-RG” set off to plow the endless expanses of space, its flight has been going on for almost five days. The unique telescope was launched into space by the Russian heavy carrier rocket "Proton-M" with the upper stage DM-03. Two hours after the launch, the Spektor-RG orbital observatory successfully separated from the upper stage. It is expected that the new X-ray telescope will occupy the vicinity of the L2 Lagrange point after about 100 days of flight, after which it will be able to start observing the Universe.
It should be noted that the "Spectrum-RG" is already the second scientific apparatus of the "Spectrum" series. The first Russian spacecraft Spektr-R (Radioastron) was successfully launched into orbit on July 18, 2011, its life cycle ended in January 2019. The third and fourth spacecraft of the Spectrum series are currently under development. These are new space telescopes Spektr-UF (Ultraviolet) and Spektr-M (Millimetron), which are being developed by Roscosmos in close cooperation with other states. The launch of these two telescopes will take place no earlier than 2025, while the international scientific community pins great hopes on them, since both projects are unique, opening up new possibilities for studying space. The devices are expected to help answer many questions in astrophysics and cosmology.
Project "Spectrum-RG"
More than 30 years have passed from the idea to the implementation of the project. The concept of a new scientific spacecraft was developed back in 1987. Representatives of the Soviet Union, East Germany, Finland, Italy and Great Britain worked together to create an astrophysical observatory. The design of the device was started in 1988. This process was entrusted to the engineers of the Lavochkin Scientific and Production Association, and the Space Research Institute of the USSR Academy of Sciences was involved in coordinating the work on the project.
The subsequent collapse of the USSR, industrial and economic problems in the late 1980s and early 1990s, and chronic underfunding of the work seriously delayed the preparation of the Spektr-RG observatory. The project was delayed, when funding appeared, new difficulties appeared. During this time, the filling and the composition of the equipment of the device have been completely updated several times, the technologies, as you know, do not stand still. The composition of the project participants also changed, in the end, in addition to Russia, Germany remained in the project. The agreement between the Federal Space Agency represented by Roscosmos and the German Aerospace Center (DLR) was signed in 2009 as part of the MAKS-2009 international aerospace show. The composition of the scientific tasks solved by the apparatus also changed, since some of them were no longer of interest to researchers. As a result, the final appearance of the spacecraft in the form in which it was launched into space was formed only a few years ago, and the process of its coordination also took some time. At the same time, our German partners also faced difficulties in the production process of the device.
In the implemented form, the new orbital astrophysical observatory "Spectrum-RG" ("Spectrum-Rengten-Gamma") is intended to compile a complete map of the Universe in the X-ray range of the spectrum. It should be noted that this is the first telescope in Russian history (taking into account the Soviet period) equipped with oblique incidence optics. For at least the next five years, the Spektr-RG observatory will become the only X-ray astronomy project in the world. As noted in Roskosmos, the survey of the entire sky by the modern orbital observatory "Spektr-RG" will be a new step in X-ray astronomy, which began to actively develop 55 years ago.
The roles in the Spektr-RG project are divided as follows. The satellite (Navigator platform) is a Russian development, the launch from Baikonur is Russian (Proton-M rocket), the main telescope is the German eROSITA, the additional, accompanying one is the Russian ART-XC. Both mirror telescopes, operating on the principle of oblique incidence X-ray optics, are unique developments that are designed to complement each other, providing the observatory with the possibility of a complete view of the starry sky with a record sensitivity never before used.
Orbital observatory "Spektr-RG"
The unique X-ray telescope, launched on July 13, consists of several main units. The Spektr-RG orbital observatory includes a basic module of service systems, the development of which was in charge of the engineers of the Russian NPO. Lavochkin. This module was developed by them on the basis of the multipurpose service module "Navigator", which had already successfully shown itself in a number of space programs. In addition to the basic module, the orbital observatory includes a complex of scientific equipment, the basis of the complex is made up of two X-ray telescopes. According to the official website of the Roscosmos company, the total mass of the fueled Spektr-RG spacecraft is 2712.5 kg, the payload is 1210 kg, the electrical power of the observatory is 1805 W, the data transfer rate (scientific information) is 512 Kbit / s, period of active scientific work - 6, 5 years.
The main equipment of the orbital observatory, which now makes its way to the L2 Lagrange point, are unique X-ray mirror telescopes created by designers from Germany and Russia. Both telescopes work on the principle of oblique incidence X-ray optics. As noted in Roskosmos, X-ray photons have very high energy. In order to bounce off a specular surface, photons must hit it at a very small angle. For this reason, the X-ray mirrors used in the telescopes of the Spektr-RG orbital observatory are specially made elongated, and in order to increase the number of registered photons, the mirrors are inserted into each other, resulting in a system consisting of several shells. Both the German and Russian X-ray telescopes are reported to consist of seven modules with X-ray detectors.
For the creation and production of the Russian X-ray telescope, which received the designation ART-XC, engineers of the Space Research Institute of the Russian Academy of Sciences, who worked in close cooperation with the Russian Federal Nuclear Center located in Sarov, were responsible. The ART-XC X-ray telescope created by Russian scientists expands the capabilities and operating energy range of the German assembly eROSITA telescope towards higher energies (up to 30 keV). The energy ranges of the two X-ray telescopes installed on board the Spektr-RG spacecraft overlap, which provides scientific equipment with an advantage in terms of increasing the reliability of research results and performing equipment calibrations in orbit.
Engineers at the Max Planck Institute for Extraterrestrial Physics were responsible for the creation and production of the German X-ray telescope, called eROSITA. As noted on the official website of Roskosmos, a scientific device created in Germany will allow for the first time in history to survey the entire starry sky in the energy range from 0.5 to 10 keV. At the same time, experts note that the telescope produced in Germany is more "big-eyed", its full field of view and angular resolution are higher than that of the Russian telescope ART-XC. At the same time, eROSITA is inferior to the Russian telescope in terms of the energy range. That is why the two X-ray telescopes on board the Spektr-RG spacecraft complement each other and are responsible for solving various problems.
Flight program and scientific significance
The scientific research program assumes that the new Spektr-RG spacecraft will be used for various astrophysical observations for 6, 5 years and will help scientists answer many questions from the field of astrophysics and cosmology. The observatory will operate for four years in the mode of scanning the starry sky, the remaining 2, 5 years - in the mode of point observation of various space objects in the mode of triaxial stabilization on the basis of applications received from the world scientific community. It is planned to observe both individual space objects of interest to scientists and selected areas of the celestial sphere. Including in the hard energy X-ray range up to 30 keV, thanks to the Russian X-ray telescope. Another 100 days (about three months) will take the space telescope flight from the Earth to the L2 Lagrange point and the first test observations of celestial bodies.
The spacecraft is not accidentally launched into orbit at the L2 point at a distance of about 1.5 million kilometers from the Earth. This point is considered the most suitable for surveys over the entire sky. As experts note, rotating around its axis (approximately corresponds to the direction to the Sun), the space observatory will be able to carry out a complete survey of the celestial sphere in six months, while the Sun will not be in its field of view. In four years of operation, the scientific apparatus will be able to perform 8 surveys of the entire sky at once, which will allow scientists to obtain a lot of new astrophysical information. At the same time, due to corrective maneuvers, it will be necessary to solve a rather complex problem, which consists in maintaining the spacecraft in orbit at a given point.
It is known that all data from the Russian telescope ART-XC will fully belong to Russia, and data from the eROSITA telescope is divided in half between Russia and Germany. As funny as it may sound, it was decided to divide the sky into two parts. All data on one half of the sky for 4 years of research, when the telescope will scan the Universe, will belong to Russia, and on the other half of the sky - to Germany. In the future, the countries themselves will decide among themselves how to dispose of the received data, how to share information with other countries and to what extent.
The main mission of the Spektr-RG apparatus is to compile a detailed "map" of the Universe in the X-ray spectrum with the nuclei of active galaxies and large clusters of galaxies. Scientists hope that in 6, 5 years of active scientific work of the observatory, it will help mankind discover hundreds of thousands of stars with active corona, tens of thousands of star-forming galaxies and about three million supermassive black holes, as well as a huge number of other objects, significantly expanding our knowledge of the Universe. will help to better understand the processes of its evolution. It is also expected that the new spacecraft will help in researching the properties of hot interstellar plasma. The work of the observatory is of great interest to all international science. In fact, the new spacecraft makes it possible to obtain data on all astronomical objects known to science.
A large-scale map of our universe that scientists have not yet had is akin to time travel, which will help answer a large number of questions. One of the most important questions that the Spectr-RG telescope will help humanity to answer is the question of how galaxy clusters evolved over the entire existence of our Universe.
