Spaceweather.com starts daily satellite-drag index from orbital data

Spaceweather.com says it has begun publishing a daily measure of atmospheric drag derived from public tracking data for a fixed sample of 1,000 Starlink satellites. The index estimates how far a typical satellite at 480 kilometers would descend in a day without thrust, giving satellite operators a running indication of changing conditions in low Earth orbit. The site compares each satellite's drag term with its own quiet-period baseline, then takes the sample's median. It checks the result against Planet Labs satellites that descend without thrusters and other constellations. Tracking data are typically a day old, and the index measures relative density rather than absolute atmospheric density.