Launched from Baikonur on July 13th 2019 to the second Sun-Earth Lagrange point (L2), the Russian-German SRG mission has now started its main task. On December 8th, after an extensive program of commissioning, calibration and performance verification of its two X-ray telescopes (ART-XC and eROSITA), the satellite has begun observing the sky in continuous scanning mode. As SRG follows the revolution of Earth, and hence also of the L2 point, around the Sun, it will perform eight complete surveys of the whole sky, one every six months, for the next 4 years. Pre-launch predictions suggest that, over that time, the eROSITA instrument, conceived, designed and built at MPE, should discover approximately 100,000 clusters of galaxies, around 3 million accreting supermassive black holes and half a million active stars.
