Bistatic Radar Detectability of Comet 67 P/Churyumov-Gerasimenko

The Rosetta spacecraft was successfully launched on 2^nd March 2004 to its target comet 67 P/Churyumov-Gerasimenko. The objectives of the Rosetta Radio Science Investigations (RSI) address fundamental aspects of cometary physics such as the mass and bulk density of the nucleus, its gravity field, its internal structure, the composition and roughness of the nucleus surface, the abundance of large dust grains, and the combined dust and gas mass flux. The dielectric properties, small-scale roughness, and rotational state of the nucleus are determined by means of a bistatic radar experiment. The radio subsystem transmitter located on board the Rosetta spacecraft will beam circularly polarized radio signals toward the nucleus surface of comet 67 P/Churyumov-Gerasimenko. Part of the impinging radiation will be scattered toward a receiver at a ground station on Earth. The bistatic radar equation (with adjustments for the irregular shape of the target) may then be used to interpret the echo signal in terms of the comet's centimeter-scale surface structure.