Even Hubble’s seeing a growing number of satellite tracks

Enlarge (credit: NASA)

A combination of space junk and a growing constellation of functional satellites like SpaceX's Starlink have astronomers worried about the potential for orbital materials to interfere with observations. And justifiably so, given that researchers are currently arguing over whether one observation represents one of the farthest supernovae ever observed or a spent Russian booster.

This clutter is obviously a big problem for ground-based observatories, which sit below everything in orbit. But several observatories, including the Hubble Space Telescope, sit in low-Earth orbit, which places them below many satellites. And a new survey of Hubble images shows that it's capturing an increasing number of satellite tracks in its images. So far, this hasn't seriously compromised its science, but it clearly shows that orbiting observatories aren't immune to these problems.

Leaving tracks

The work came from a citizen science project, the Hubble Asteroid Hunter, which organized volunteers to search for the tracks asteroids left in long-exposure Hubble observations. If an asteroid happens to pass through Hubble's field of view during this exposure, it can leave a short streak in the resulting image. But the participants started noting that some of the streaks they were seeing crossed Hubble's entire field of view during a single image (the project maintains a forum where the volunteers can discuss their work).