Space telescopes are being photobombed by satellites, and the problem is slated to get much worse
Summary
NASA-led research modelled the impact of the rapid rise in low Earth orbit (LEO) communications satellites on space telescopes that operate between roughly 450 and 800 km altitude. Using a database of planned launches, the team looked at Hubble and three planned/operating LEO telescopes (SPHEREx, ESA’s ARRAKIHS concept and China’s Xuntian). They found that, if current constellation plans go ahead, almost 40% of Hubble images could be affected by satellite light contamination and up to 96% of images from the other telescopes.
Satellite counts have climbed from about 2,000 in 2019 to roughly 15,000 today, and filings suggest numbers could swell to around 560,000 by the 2030s. The researchers estimated average satellites per exposure of 2.14 for Hubble, 5.64 for SPHEREx, 69 for ARRAKIHS and 92 for Xuntian under those plans. The study appears in Nature and recommends mitigation steps — for example keeping satellites in lower orbits than telescopes — though that solution could carry environmental costs such as effects on the ozone layer. The authors emphasise that space telescopes are not immune to man-made light contamination. Note: the James Webb Space Telescope at L2 is not affected by LEO traffic.
Key Points
- Planned satellite constellations could raise the LEO population to ~560,000 by the 2030s if filings are realised.
- NASA-led modelling suggests ~39.6% of Hubble exposures and up to 96% of some LEO telescope images would be contaminated by satellite light under those plans.
- Estimated average satellite streaks per exposure: Hubble 2.14, SPHEREx 5.64, ARRAKIHS 69, Xuntian 92.
- Historical scans (2002–2021) showed ~2.7% of Hubble images had satellite trails; projected contamination is far worse.
- Potential mitigation includes placing satellites below telescope altitudes, but this may have environmental trade-offs (eg. ozone impacts).
- Researchers call for actions to predict, model and correct satellite light contamination and for coordination between satellite operators and the science community.
Author’s take
Punchy and to the point: this isn’t just an annoying streak across a pretty picture — it’s a real threat to the science those telescopes were built to deliver. If constellation plans proceed unchecked, many LEO missions will face severe data degradation. Regulators, operators and astronomers need to move faster to reduce the damage.
Why should I read this?
Short and blunt: if you like clean, useful images of the universe (or you rely on them for research), this is proper bad news. The satellite boom is already affecting pictures and will get a lot worse unless people sort it out. Read it to find out which telescopes are at risk and what fixes might actually work.