https://www.scientificamerican.com/article/spacex-tests-black-satellite-to-reduce-ldquo-megaconstellation-rdquo-threat-to-astronomy/

The aerospace company SpaceX launched 60 of its Starlink broadband Internet satellites into orbit on 6 January — including one, called DarkSat, that is partially painted black. The probe is testing one strategy to reduce the brightness of satellite ‘megaconstellations’, which scientists fear could interfere with astronomical observations.

Various companies plan to launch thousands of Internet satellites in the coming years; SpaceX, of Hawthorne, California, aims to launch 24 batches of Starlinks this year. By the mid-2020s, thousands to tens of thousands of new satellites could be soaring overhead. Bright streaks caused by light reflecting off them could degrade astronomical images.