The Soil Moisture and Ocean Salinity (SMOS) mission was launched on 2 November 2009. It is one of the European Space Agency's Earth Explorer missions, which form the science and research element of the Living Planet Programme.
The payload of SMOS consists of the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) instrument, a passive microwave 2-D interferometric radiometer, operating in L-band (1.413 GHz, 21 cm) within a protected wavelength/frequency band. The SMOS mission is based on a sun-synchronous orbit (dusk-dawn 6am/6pm). SMOS measurements are made over a range of incidence angles (0 to 55°) across a swath of approximately 1000 km with a spatial resolution of 35 to 50 km. MIRAS can provide measurements in dual and full polarisation, with the latter being its present operating mode.