ESA Earth Explorer 9 candidate selected in November 2017 for competitive feasibility study, SKIM (Sea-surface Kinematics Multiscale monitoring) would use a wide-swath scanning multibeam Doppler radar altimeter to measure ocean-surface currents globally every few days, improving understanding of ocean–atmosphere exchange and rapidly changing Arctic and equatorial dynamics. FORUM was subsequently selected for Earth Explorer 9 implementation; SKIM remains a documented research concept rather than an implemented mission.