SKIM carries one main instrument, the SKIM Ka-band radar, or SKaR instrument. The instrument combines an accurate state-of-the-art nadir-looking altimeter with novel Doppler enabled wave and current scatterometer capabilities. The instrument uses heritage from the SWIM instrument, developed by CNES, and currently flying on the Chinese-French CFOSat mission. The antenna concept is that of a multi-beam conical scanner, with an offset reflector illuminated by a set of feed horns on a rotating plate. With respect to its predecessor, SKIM adds a Doppler capability to measure motion of the ocean surface.
The SKaR observation principle is to gather sparsely distributed samples by scanning a set of beams across a wide swath of approximately 300 km.