The streak from a Starlink satellite appears in this image of the Andromeda galaxy, taken by the Zwicky Transient Facility, or ZTF, during twilight on May 19, 2021. .

"We don't expect Starlink satellites to affect non-twilight images, but if the satellite constellation of other companies goes into higher orbits, this could cause problems for non-twilight observations," Mróz said.

We found that twilight observations are particularly affected: a fraction of streaked images has increased from less than 0.5% in late 2019 to 18% in August 2021.

Once SpaceX deploys 10,000 Starlinks, essentially all ZTF images taken during twilight may be affected.