Overview
- Researchers reported Wednesday that debris in low Earth orbit starts falling faster once solar activity reaches about two‑thirds of a cycle’s peak.
- Lead author Ayisha M Ashruf and colleagues at ISRO’s Vikram Sarabhai Space Centre analyzed 36 years of tracking data for 17 legacy objects and published the study in Frontiers in Astronomy and Space Sciences.
- Stronger solar output heats and expands the thermosphere, which raises air density at orbital heights of roughly 160 to 2,000 kilometers and increases drag that slows objects and pulls them lower.
- The threshold pattern appeared in three consecutive solar cycles from 1986 to 2024, with debris at 600 to 800 kilometers losing a few kilometers of altitude once the sunspot level crossed the breakpoint.
- The team says satellites will need more frequent orbit corrections and fuel during high solar activity, which may shift launch windows and collision‑risk estimates in today’s crowded low Earth orbit.