PACE

PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) is a NASA Earth science satellite launched on 8 February 2024 into a sun-synchronous polar orbit at 676.5 km altitude, 98-degree inclination, with a 13:00 local equatorial crossing time and approximately 2-day global revisit.^[1] The mission carries three instruments: the Ocean Color Instrument (OCI), a hyperspectral push-broom radiometer covering ultraviolet through shortwave infrared (340-2260 nm) for ocean colour and atmospheric characterisation; SPEXone, a Dutch multi-angle spectropolarimeter developed by SRON for aerosol microphysical property retrieval; and HARP2, a hyper-angular wide-coverage polarimeter developed by UMBC for cloud and aerosol characterisation.^[2][3][4] PACE is designed to advance understanding of phytoplankton community composition, marine primary productivity, harmful algal bloom dynamics, and fine-mode and coarse-mode aerosol properties including their interaction with clouds.^[1] Initial science data were publicly released following commissioning completion in April 2024.^[5]