Asteroid hunters worry megaconstellations might interfere with planetary defense

Adding to the astronomy community's general apprehension about the growing number of satellites in low Earth orbit (LEO), a number of planetary defense scientists and researchers have voiced their own concerns about the topic.

Apollo Academic Surveys and Carrie Nugent of the Olin College of Engineering in Massachusetts surveyed planetary defense experts on a range of topics regarding near-Earth asteroids (NEA) and comets. Of the 34 experts polled, all of them said they were at least slightly concerned about the effect of satellite overcrowding on asteroid detection; 24% identified as extremely concerned.

"Studies (e.g. Mroz et al. 2022) have shown that LEO satellites can severely affect observations taken during twilight, and that is an important parameter space for NEO search," wrote one anonymous survey participant.

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Another respondent pointed to the potential issue of launching a mitigation mission — for example, an asteroid deflector like NASA's DART mission — through a "flood of artificial satellites."

"I think it's absolutely terrible that nothing concrete is being done to combat this issue," wrote Cristina Thomas of Northern Arizona University. "This is only going to get worse and make a lot of problems for ground-based discovery."

But there is hope yet. Some experts pointed to space-based observation systems, such as the NASA space telescope NEO Surveyor that the agency hopes to launch in 2028, as the future of monitoring potential threats. "Space-based assets are the correct advancement of NEO discovery. Ground-based search assets are of diminishing importance," wrote another anonymous survey participant.

And as for ground-based observations, researchers may be able to develop software to filter out most interference from artificial satellites, just as astronomical observers have worked to do.

"A well-designed, NEO-focused survey can be made robust against losing occasional images (or fractions of images) due to satellite trails," wrote Eric Christensen of the University of Arizona, who serves as the principal investigator of the Catalina Sky Survey, one of the two asteroid-spotting programs with the most detections to its name, according to NASA. "I've estimated that a fully built-out Starlink megaconstellation may degrade Catalina Sky Survey's detection efficiency by a few tenths of a percent." 

But he does note that other astrophysical surveys "may be more susceptible to additional 'noise' from satellite trails."

The survey results have been published by Apollo Academic Surveys.

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