Growing Starlink constellation could affect future space observations

A new study on the satellites' impact has been published in The Astrophysical Journal Letters.

Astronomers are concerned about the effect that SpaceX's Starlink satellite constellation could have on their scientific observations as the constellation grows in size. Currently standing at almost 1,800 satellites orbiting at an altitude of roughly 550 kilometers (341 miles), SpaceX plans to expand the constellation to 10,000 satellites by 2027.

A team of researchers analyzed archival images taken by the National Science Foundation (NSF)-funded Zwicky Transient Facility (ZTF), operating out of Caltech's Palomar Observatory, which scans the entirety of the night sky every two days, cataloging changes. In images taken between November 2019 and September 2021, researchers identified 5,301 satellite streaks. They are most apparent during twilight observations taken at dawn or dusk, the most critical time in finding near-Earth asteroids.

"In 2019, 0.5 percent of twilight images were affected, and now almost 20 percent are affected. 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," says Przemek Mroz, study lead author and a former Caltech postdoctoral scholar who is now at the University of Warsaw in Poland.

Scientists expect that almost all ZTF images taken during twilight will contain at least one streak in the future. However, the paper shows that a single streak affects less than 0.1% of pixels in a ZTF image.

"There is a small chance that we would miss an asteroid or another event hidden behind a satellite streak, but compared to the impact of weather, such as a cloudy sky, these are rather small effects for ZTF," continued Mroz.

You can read more from the study here.