English: Fig. 1: Examples of satellite trails identified in HST individual exposures and composite images. a, Examples of satellite trails in individual HST ACS/WFC exposures (one aperture image, cutout FoV of roughly 101′′ × 202′′), with a typical integration time of 11 min: the first column shows typical trails (observation IDs j8cw52p3q and j8pu0hcfq); the second column shows multiple trails in an exposure ( j8xi1bafq) and flickering satellite trail ( jbhj04gcq) and the third column shows broad out-of-focus trail ( ja4tg4lsq) and curved satellite trail ( jcor25dtq). b, Imperfectly removed satellite trails in composite HST images, as identified by AutoML with bounding boxes in cutouts of HST composite images.
Abstract: The recent launch of low Earth orbit satellite constellations is creating a growing threat for astronomical observations with ground-based telescopes1–10 that has alarmed the astronomical community11–16. Observations affected by artificial satellites can become unusable for scientific research, wasting a growing fraction of the research budget on costly infrastructures and mitigation efforts. Here we report the first measurements, to our knowledge, of artificial satellite contamination on observations from a low Earth orbit made with the Hubble Space Telescope. With the help of volunteers on a citizen science project (www.asteroidhunter.org) and a deep learning algorithm, we scanned the archive of Hubble Space Telescope images taken between 2002 and 2021. We find that 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. This fraction depends on the size of the field of view, exposure time, filter used and pointing. With the growing number of artificial satellites currently planned, the fraction of Hubble Space Telescope images crossed by satellites will increase in the next decade and will need further close study and monitoring.