Refinement of the solar radiation pressure model for the SWOT satellite

The NASA-CNES climate science Surface Water and Ocean Topography (SWOT) satellite was successfully launched in December 2022. This mission embodies the longstanding cooperation between CNES and NASA Jet Propulsion Laboratory in space oceanography for 40 years, initiated with TOPEXPoseidon in 1992, subsequently pursued through the Jason series of satellites (1 to 3 between 2001 and 2016) and continued in 2020 with the Copernicus Sentinel-6 mission.

SWOT is the first space mission that will study nearly all of the water on the Earth’s surface. To complete this global survey and mapping of the finer details of the ocean’s surface topography and water bodies over time, the satellite is equipped with a GPS (Global Positioning System) and DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) dual-frequency receivers, as well as a Laser Retroreflector Array (LRA) to support verification of the challenging Precision Orbit Determination (POD) requirements

 

In this poster, we will present the current results and efforts underway to improve the modeling of Solar Radiation Pressure (SRP). Residual signatures of systematic errors related to the Sun’s elevation angle are observed in-flight when using the current a priori SRP model. To address this issue, we analyze once-per-revolution empirical along-track and cross-track accelerations with respect to the beta prime angle, aiming at reducing this dependency. An updated box-wing model is thus derived for SWOT moving from pre-launch to adjusted data (geometry, surface properties).