The BISSAT mission: A bistatic SAR operating in formation with COSMO/SkyMed X-band radar

BISSAT mission has been funded by the Italian Space Agency for a competitive Phase-A study along with five other missions. Its concept consists in flying a passive SAR on board a small satellite, which observes the area illuminated by an active SAR, operating on an already existing large platform. To this end, two quite different satellites must fly in formation in order to guarantee bistatic coverage within the range of latitude 65.2°S-66.2°N. In particular, the orbit selection for the passive satellite leads to the same orbit as for the primary radar with a difference in the ascending node right ascension and in the time of the passage on the ascending node. The main critical aim, consisting of superimposition of passive and active radar swaths, is achieved by ad-hoc steering radar antennas along the orbit. Design is critical because two existing buses, which have been developed for different purposes, are used.