Harnessing Satellite Constellations as Signals of Opportunity for an Enhanced Specification of the Satellite Drag Environment in the Critical LEO Regime

Enhancing the accuracy of orbit predictions for low‐Earth orbit (LEO) satellites and debris is vitally important for satellite owner/operators dedicated to ensuring the safety and sustainability of the LEO environment. Presently, the largest source of error in orbit predictions stems from uncertainties in the estimation of thermospheric mass density, driven primarily by a lack of measurements used to accurately refine thermospheric models. This work addresses the pressing need for thermospheric observations by harnessing the SpaceX Starlink constellation as a signal of opportunity for atmospheric specification. Leveraging continuous ephemeris, attitude, and housekeeping data from over 1,500 Starlink satellites—provided through a partnership between SpaceX and NOAA's NESDIS and SWPC offices—orbit‐effective density measurements are obtained by monitoring the dissipation of orbital energy with Global Navigation Satellite System tracking and augmenting data from the Starlink onboard navigation filter with a high‐fidelity, physics‐based characterization of the nonconservative forces and aerodynamic force coefficients. The analysis emphasizes the sensitivity of the derived densities to the applied gas‐surface interaction model (GSIM), with different parameterizations yielding distinct density estimates and highlighting limitations at high incidence angles. The study also shows that the choice of thermospheric model used for validation influences the interpretation of the derived densities, as well as the perceived accuracy of the GSIM. This research showcases the potential of satellite constellations to provide thermospheric observations with unprecedented spatial coverage and contribute to an accurate specification of the satellite drag and thermospheric environments.