While I recognize a lot of people have returned to a fairly normal life now that we have vaccines, I have to admit I’m one of the high-risk individuals who is still not really leaving my house. This means my world has become the before times, the infinite Blursdays of plague times, and a question mark over the future as I wonder how much different the post-COVID world is going to be.

One of the weird leaps the world is making is toward a sky filled with low-Earth-orbit satellites. In early 2020, the last face-to-face American Astronomical Society meeting I or anyone else attended highlighted the potential social good and astronomical horror of the still-novel Starlink satellites. We all wrote our think pieces and went home to experience a pandemic, and I have to admit that not nearly as much energy has gone into worrying about these tiny spacecraft as might have been expended if we were actively hosting star parties, observing sessions with students, or otherwise going out to observe the now interrupted sky.

While many of us have literally stayed home, survey telescopes have continued their largely robotic missions to seek out the things that flicker, flare, and move in the night. One particularly successful scope, the Palomar Zwicky Transient Facility, has been doing its best to alert us to scientifically awesome supernovae, and in a new paper in The Astrophysical Journal Letters, to the scientifically disturbing Starlink satellites. In this paper, led by Przemek Mróz, researchers document the ever-increasing impact of Starlink on their images. According to Mróz: In 2019, 0.5 percent of twilight images were affected, and now almost 20 percent are affected.

This is where I need to let you know that the kinds of asteroids astronomers are most worried about are the kind we are most likely to discover in the twilight sky near the Sun. Those images are important.

The reason only twilight images are affected is that the current Starlink satellites are so low in the sky that they are in the Earth’s shadow about the time twilight ends. Missions in much higher orbits can be illuminated longer and affect more of the night. Mróz goes on to say: 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.

As we have quantified that Starlink will cause harm to our ability to do science, including the kinds of science that watch for incoming asteroids, it is important to remember that Starlink promises that it will open the world to high-speed internet. Right now, I want proof. 

I know of many affluent people who have Starlink for their cabins in the woods, their homes off the grid, and the like. I want to see Starlink doing good, helping us reconnect in emergencies and making the world safer. There are amazing opportunities for Starlink to prove itself. They could readily partner with aid agencies to take solar panels and Starlink ground stations into Tonga and other places knocked offline by natural disasters. If we are going to need to lose our sky, I want to see us regain contact with one another.

More Information

Caltech press release

“Impact of the SpaceX Starlink Satellites on the Zwicky Transient Facility Survey Observations,” Przemek Mróz et al., 2022 January 14, The Astrophysical Journal Letters