Astronomer Dr. Tony Phillips has discovered that SpaceX's Starlink satellite constellation, alongside other commercial satellite networks, can serve as a "planetary barometer" to monitor Earth's atmospheric density and behaviour. By analysing orbital decay data from thousands of satellites, Phillips can measure how the atmosphere expands and contracts in response to solar activity and geomagnetic storms. This approach is significant because it provides a novel scientific tool using existing infrastructure and publicly available data, without requiring new instruments to be launched.

Phillips analyses orbital tracking data from 1,000 Starlink satellites, 107 Planet Labs SuperDoves, 391 Amazon Kuiper satellites, and 651 Eutelsat OneWeb satellites—each orbiting at different altitudes—to create a daily index of atmospheric conditions. The data reveals that the upper atmosphere responds to solar ultraviolet radiation changes with approximately a two-day lag, whilst geomagnetic storms cause more rapid atmospheric expansion and accelerated orbital decay. Whilst other scientists have previously used Starlink data for similar atmospheric studies, Phillips's contribution is establishing the first public, continuously updated index using three independent satellite constellations to cross-check findings.