Sea Surface Temperature (SST) and Ocean Vector Winds (OVW) are fundamental variables for understanding, monitoring and predicting the general circulation of the ocean and atmosphere. OVW drive ocean currents and ocean vorticity through the transfer of energy to the ocean as frictional coupling at the atmosphere- ocean interface (the momentum flux expressed as drag force per unit area). The dynamic patterns of SST and OVW are important predictors of global climate with far reaching consequences for the global economy and security of life and property. Changes in the patterns of SST reveal the dynamic structure of surface currents and other OVW driven features such as tropical instability waves and the magnificent western boundary currents of the global ocean. While current satellite instrument technologies provide passive microwave observations of SST and OVW/wind-stress, these data are limited in resolution and geographic coverage. Ideally a higher spatial resolution (~10 km) all weather SST and OWV dataset that can observe globally including the coastal and ice infested water is required. Starting from agreed scientific user requirements, a baseline Instrument design has been developed during the project. The proposed instrument is a passive microwave conical scaning (at 53 deg incidence) total power radiometer. It uses a large reflector antenna to achieve 15 Km of spatial resolution at 6.9 GHz. Compared to existing instruments (e.g., AMSR-E having a 74x43 Km IFOV, 56 Km mean spatial resolution @ 6.9 GHz) Microwat is almost 4 time better. The Microwat instrument sensitivity is doiuble that of current instruments due to a larger bandwidth and a longer measurement integration time. Microwat is RFI resistant and includes specific digital hardware for RFI detection and mitigation using both temporal and frequency segmentation of measurments. Microwat will measure wind vector using polarimetric channels at 6.9 & 18.7 GHz. The mission has been developed to fly in tandem with METOP ASCAT providing complementary surface wind information at high wind speeds (where scatterometer are not ideal bue to suppression of Bragg scatterers) across the full swath and will fill the “Ascat gap”. Microwat calibration is based on internal targets (Matched load, Active Cold Load and Noise Diode) and external reference targets. High frequency channels (such as 89 GHz for sea ice detection) could be added to the design as the centre part of the reflector is solid with high stiffness and a highly reflective coating. The project also investigated the momentum compensation of the rotating antenna subsystem.