Dec 3, 2019 - Science

Thousands of new satellites could make asteroid hunting harder

Illustration of a satellite blocking the view of many asteroids in the background

Illustration: Sarah Grillo/Axios

Astronomers are worried the influx of new satellites in the coming years could impede the hunt for asteroids near Earth.

What's happening: Companies like SpaceX and Amazon are planning to launch thousands of internet-beaming satellites to low orbits. The new spacecraft are already changing the night sky — SpaceX's Starlink satellites can be seen shooting across astronomers' images.

Why it matters: Scientists have spotted most of the largest known asteroids near our planet, but there are still thousands of smaller, possibly dangerous ones they've yet to find.

  • The rise of mega-constellations could make the hunt for those asteroids harder — and costlier — in the future, some experts warn.
  • Asteroid hunters already have to contend with satellites in orbit, but in the future, they may need to find new ways to account for the satellites streaking through images, including developing new and possibly expensive software, European Space Agency astronomer Rüdiger Jehn told Axios.

How it works: Ground-based telescopes hunt for asteroids by taking photos of the sky over the course of a night in order to pick out faint asteroids near Earth.

  • Some telescopes make use of the time right after sundown and right before sunrise in order to best spot near-Earth asteroids, but that's also the same time when satellites are most visible, with sunlight glinting off of them.

The big picture: For decades, radio astronomers have had to contend with radio signals emitted by satellites, but astronomers working with visible light haven't necessarily had to worry too much about satellites.

  • Some researchers now think it might be too late to exert much influence over how these mega-constellations are designed and how they affect astronomy.
  • "The astronomy community dropped the ball," astronomer Jonathan McDowell told Axios. "We should have been on this 10 years ago and we didn't see it coming."

Yes, but: Companies responsible for these satellites say they want to be sure to protect astronomers' view of the night sky even with thousands of new spacecraft up in orbit.

What's next: If these mega-constellations do interfere with ground-based asteroid detection, it places more importance on launching a space-based asteroid-detecting telescope, experts say.

  • A system able to hunt for asteroids from space would not have to contend with the streaking satellites above Earth.
  • However, ground-based and space-based telescopes complement one another, further emphasizing the need to protect observatories on the ground as well, experts say.
Go deeper