Dark Skies and Bright Satellites: The Threat to Ground-based Astronomy

We have reached a strange situation in time. Space technology, which was originally driven by the quest for the stars and space, has reached a point where it threatens our view of the skies and observations by ground-based telescopes. The first mass launch of 60 Starlink satellites on 23 May 2019 by SpaceX shocked astronomers worldwide with the obvious threat it posed to clear, dark skies. While on the one hand, there is the promise of broadband internet to underdeveloped and inaccessible areas of the globe, on the other hand, the brightly lit sky with trails of thousands of satellites is a heavy price and threat to all ground-based and space-based observations. These ‘megaconstellations’ will flood the skies in the near future and are a threat to astronomical observations. Satellites will be brighter than 99% of the present objects in orbit. In this article, we shall discuss the challenges posed to observatories by the exponential growth in satellite constellations and steps being taken to engage with the parties involved to (partially) solve these issues and the efforts being made to mitigate these effects. We shall also introduce the proposed activities of the recently set up IAU Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference.