SEASTAR is a new Earth Explorer mission concept dedicated to observing small-scale ocean surface dynamics in coastal seas, continental shelf seas and Marginal Ice Zones (MIZs). The mission proposes to measure two-dimensional vector fields of total surface current vectors (TSCV) and ocean surface vector winds (OSVW).

SEASTAR is the first mission to offer the sensitivity, fine resolution, high accuracy, wide swath and flexible sampling to observe and characterise these small-scale phenomena. Using highly innovative squinted along-track interferometry on a single independent satellite, SEASTAR will, for the first time, quantify these fast-evolving processes on daily to multi-annual scales, across different ocean conditions and latitudes, over all coastal and shelf seas and MIZs.

The primary scientific objectives of SEASTAR are:

  • to measure, for the first time, two-dimensional fields of total surface current and wind vectors at 1-km resolution, with high accuracy, over all coastal seas, shelf seas and MIZs, to characterise their magnitude, spatial characteristics, regional extent, and temporal variability on daily, seasonal to multi-annual time scales
  • to deliver, for the first time, accurate high-order derivative products (e.g., vorticity, strain, divergence) to explore the relations between ocean sub-mesoscale/mesoscale circulation, air-sea fluxes and vertical exchanges
  • to investigate the relations between small-scale dynamics, air-sea interactions, vertical processes and marine productivity using synergy with high-resolution satellite data from optical, thermal and microwave sensors
  • to validate high-resolution and coupled models and support the development of new parameterisations to improve operational forecasts and reduce uncertainties in climate projections.

SEASTAR is one of four mission candidates selected to proceed to ESA Earth Explorer 11 Phase 0. If selected, SEASTAR will launch in the 2031/32 timeframe.