We've Turned Starlink into a Planetary Barometer
6 hours ago
- Starlink satellites, despite downsides like interfering with astronomy and debris, are used as ad hoc barometers measuring atmospheric drag through a daily 'sink rate' index.
- The sink rate measures how many meters per day a typical Starlink at 480 km would lose altitude without thrusters, varying from 19.7 m/day (quiet) to 127.6 m/day (during geomagnetic storms).
- SpaceX maneuvers and solar activity cause daily changes; the index is derived from TLE data of 1,000 Starlinks and calibrated using Planet Labs Doves.
- Other constellations (Kuiper, OneWeb) provide cross-checks, with drag increasing at different altitudes during storms, peaking around 550 km.
- This public, daily index helps calibrate thermospheric density models, reducing uncertainty in orbit prediction and collision avoidance.