The miniSAR, proposed by the Applied Physics Laboratory, USA, is a multifunction instrument working as a synthetic aperture radar imager, an altimeter, scatterometer or radiometer. The radar operates at 2.5GHz with a maximum peak RF power of 20W. The primary antenna transmits a right circular polarized (CP) signal, while receiving the dual polarized, i.e., right as well as left circularly polarized signal. The radar observes the lunar surface at 45◦ incidence angle, recording echoes in both the orthogonal directions and creates an image. It has a resolution of 100 meters per pixel but in spotlight or low altitude mode, it has a resolution of 10m/pixel. In the scatterometer/altimeter mode, the system will be nadir pointing and functions as a backscatter imaging radar with 300 m/pixel resolution. The radiometer, measuring the RF surface emissivity, is capable of measuring lunar surface temperatures in the range of 100–400K, with a precision of 1K, with a spatial resolution of 1 km. The meter scale surface roughness will be determined in the footprint. The circularly polarized ratio (CPR) will allow characterization of the physical properties of the lunar surface like dielectric constant and porosity.
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