The European Space Agency says the Gaia astrometry satellite has been hit by a space disaster. A micrometeoroid punctured its protective shell, and a major solar storm in May knocked out a critical CCD sensor. Engineers have gotten the satellite back online, although the amount of data it can collect appears to be greatly reduced.
Image source: ESA
The Gaia satellite is located at the L2 Lagrange point (in the shadow of the Earth on the opposite side from the Sun). Its huge CCD field and two telescopes receive data on millions of stars every second, allowing us to track their speeds and directions. In fact, Gaia creates a three-dimensional dynamic map of our galaxy and even looks beyond its borders. The importance of this data cannot be overestimated, and in many ways it has not even been studied, such a rich array of information it represents.
In April, a micrometeoroid hit the satellite’s protective casing. It entered at the “wrong” angle and with a high speed that the casing could not compensate for. In the Earth’s atmosphere, such a speck of dust would have instantly evaporated. But for Gaia, its impact had consequences. Scattered sunlight began to enter through the hole made by the micrometeoroid, which created false alarms on the matrix – it began to show non-existent stars.
While engineers were solving the problem of reducing the sensitivity of the satellite matrix to compensate for the damage, a new problem arose. In May, the CCD matrix, which worked as a control matrix to filter out false alarms from the stars, failed. Engineers cannot name the exact cause of the failure, but they associate it (in terms of time) with the strongest solar storm in many years, the effect of which in the form of aurorae was visible even in the Krasnodar Territory. The satellite worked almost twice as long as its allotted 6 years, and the electronics could have significantly worn out under constant cosmic radiation.
Milestones in Gaia’s 10-year mission
Therefore, after solving the problem of extinguishing scattered sunlight through a hole in the protective casing, engineers lowered the sensitivity threshold of the main matrix to eliminate the appearance of false stars. The work on restoring the observatory was successfully completed. Moreover, the recalibration of the telescopes increased the accuracy of measurements to a level that the satellite had never had before. Today, the observatory transmits 25 GB of data to Earth every day. There would be much more if the onboard equipment did not work to compensate for false alarms. But even this data stream is an invaluable contribution to the study of the Universe.
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Source: 3dnews.ru
