A sharp Hubble.
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The Hubble Space Telescope, which was delivered into orbit on April 24, 1990, in the cargo bay of the Discovery Shuttle, is the most famous among such observatories. With its main mirror of 2.4 meters in diameter, Hubble remained the largest optical instrument in space, until in 2009 the European Space Agency launched the Herschel Space Observatory with a mirror diameter of 3.5 meters.
The history of Hubble was not without problems. Having started work in space, he gave out the image worse, than the same size ground telescope. The reason for the distortion was a mistake made in the manufacture of the main mirror. The project could have failed completely if the specialists, who had learned the bitter experience of breakdowns on the previous observatories, had not foreseen the possibility of repair by astronauts. Kodak quickly made a second mirror, but it was impossible to replace it in space, and then the engineers proposed to make space "glasses" - the system of optical correction COSTAR from two special mirrors. To install it on the Hubble, on December 2, 1993, the shuttle Endeavour went into orbit. Astronauts have made five most difficult exits into outer space and returned the expensive telescope in operation.
Later astronauts flew to the "Hubble" four more times and significantly extended its life. Last maintenance passed from May, 11 till May, 24th, 2009, within the limits of the mission of a shuttle "Atlantis".
Today, the telescope, which is almost thirty years old, begins to break down. In October last year, NASA's press office reported that it refused one of the gyroscopes of the orientation system, because of which the "Hubble" was transferred to "safe mode" for three weeks (turns off the research equipment, works the only service).
On January 8, the Wide Field Camera 3 turned off; it took nine days to troubleshoot and fix the problem. On February 28, due to an error in the program code, the ACS (Advanced Camera for Surveys) multispectral camera did not work for several days. So far, the ground handling team has been coping with the growing problems, but the telescope is unlikely to last long.
Now it is planned that "Hubble" will continue work till June 30, 2021, that as much as it is much more than its safety factor. Then the telescope will try to bring under control from an orbit and to flood in the ocean. However, now the administration of President Donald Trump considers other variants: corporation the Sierra Nevada offers to send to "Hubble" the ship-repairman.
On the other hand, a large infrared telescope James Webb Space Telescope with a composite mirror with a diameter of 6.5 meters awaits its turn long ago: it is planned to be launched on March 30, 2021. Among other tasks, he will search for the light of the oldest stars and galaxies, study their evolution and the formation of clusters of matter in the young universe. In addition, Webb will help to search for relatively cold planets in neighboring stars - but most importantly, it will capture the spectra of their atmospheres. Then we will be able to speak more confidently about the natural conditions reigning there, and maybe even record the signs of life - biosignature.
Faraway and nearby.
Today, the section of astronomy that studies exoplanets is in its infancy. Previously, massive solids in star systems were found on an indirect basis - the gravitational influence on one's own luminescence - but now the transit method, i.e. observation of micro eclipses of the star, has become the most popular. Of course, it requires the highest accuracy of measurements, and the best result is obtained by space telescopes because it is difficult to distinguish the change of luster of distant luminaries from the fluctuations of the restless earthly atmosphere.
The standard in this field of research was set by the American telescope Kepler Telescope, launched on March 7, 2009. He was able to observe up to 100,000 stars simultaneously, collecting statistics on exoplanets. In three years of work, Kepler managed to find 4700 candidates for exoplanet; over 2600 of them were confirmed. Many open worlds were comparable in size to the Earth. It was also possible to prove the existence of systems with several exoplanets at once, including double stars.
There were even land-like worlds in the "inhabited areas", i.e. at such a distance from the star, which is convenient for life. For example, the planet Kepler-438b, which is 470 light-years away from us, is today considered the most suitable planet for the emergence and development of another life. Unfortunately, the work with Kepler was accompanied by technical failures and was discontinued in October last year.
Galactic Astronomy doesn't stand still either. In April 2018, Europeans published preliminary results of observations of the Gaia telescope, launched five years ago. Based on these results, a detailed three-dimensional map of the Milky Way was created, containing information on the exact location, characteristics, and movement of 1.7 billion stars. In addition, Gaia has collected information about 14,000 solar system asteroids. The telescope will transmit data to Earth, enriching our knowledge of near and far space, until the end of 2020.
Against the background of such impressive achievements of Russian orbital astronomy, there is nothing to boast of so far. Now in orbit is only the RadioAstron telescope (Spektr-R), launched on 18 July 2011: it was engaged in the study of black holes, neutron stars and other objects emitting in the electromagnetic spectrum. Although the telescope's warranty period expired in 2016, until recently it had been working properly and had lost control only on 10 January 2019, and data were still being transmitted. The scientists intend to repeat the attempts to restore bilateral communication until mid-May.