Space may be unfathomably vast, but the slice that surrounds our planet is growing increasingly crowded. In particular, the growing network of satellites in orbit is having an increasingly negative effect on the Hubble Telescope, according to a paper published in Nature.
“Observations affected by artificial satellites can become unusable for scientific research,” Dr. Sandor Kruk of the Max Plank Institute for Extraterrestrial Physics and his co-authors wrote.
With that concern in mind, Kruk and his team used “volunteers on a citizen science project and a deep learning algorithm” to scan 20 years of Hubble Space Telescope images taken between 2002 and 2021.
The Hubble Space Telescope is known for recording awe-inspiring images of the cosmos. But thousands of satellites launched by private companies like SpaceX are photobombing those images with streaks and light curves that can be impossible to remove. https://t.co/uxdbUpGvOy pic.twitter.com/DfgPnzuw6m
— The New York Times (@nytimes) March 2, 2023
What they discovered is a small — but not trivial — amount of Hubble long-exposure images are streaked with light from satellites.
“A fraction of 2.7% of the individual exposures with a typical exposure time of 11 minutes are crossed by satellites and that the fraction of satellite trails in the images increases with time,” the researchers found.
What fraction? That depends on exposure time, the field of view, and other factors. But it’s a problem. And it might be small for now, but it’s growing worse.
Can remove some streaks but not all
“Most of these streaks are readily removed using standard data reduction techniques, and the majority of affected images are still usable. Satellite streaks do not currently pose a significant threat to Hubble’s science efficiency and data analysis,” NASA spokesperson Claire Andreoli told Business Insider.
“It’s certainly an overstatement to say that everything with a streak is ruined, but I think it’s an understatement to say that it doesn’t matter,” pushed back Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics, who was not involved with the paper. “Some of them are not usable.”
Within the yellow boxes are the results of imperfectly removed satellite streaks, achieved using digital technology. Photo: NASA, Sandor Kruk et al.
As the above photo illustrates, using data reduction techniques to remove the streaks isn’t always possible. And it’s the “currently” in NASA’s statement above that worries scientists.
In 2010, there were roughly 1,000 satellites in orbit. By 2027, SpaceX alone hopes to have 42,000 satellites up there.
And SpaceX isn’t the only company with such ambitions. Telesat, OneWeb, and Amazon all have constellations in the works. The paper’s authors estimate that by the time Hubble leaves service in the mid-2030s, 33 to 41 percent of Hubble’s images could include a satellite streak.
Boosting Hubble into a higher orbit could be a solution. The telescope’s orbit has been in natural decay since it was launched in 1990. In 2022, NASA and SpaceX announced plans to explore that possibility, but neither organization has released an update since the original announcement.
