The Sentinel-3 satellite carries the following payload instruments:

• a push-broom imaging spectrometer instrument called the Ocean and Land Colour Instrument (OLCI)
• a dual view (near-nadir and backward views) conical imaging radiometer called the Sea and Land Surface Temperature Radiometer (SLSTR) instrument
• a dual-frequency SAR altimeter called the SAR Radar ALtimeter (SRAL) instrument
• a Microwave Radiometer (MWR) instrument, supporting the SRAL in achieving overall altimeter mission performance by providing wet atmosphere correction
• a Precise Orbit Determination package including a Global Navigation Satellite Systems (GNSS) instrument, a Doppler Orbit determination and Radio-positioning Integrated on Satellite (DORIS) instrument and a Laser Retro-Reflector (LRR).

Figure 1: Sentinel-3 Payloads (Credit: ESA)