This paper presents a novel concept which we call a Correlating SAR (CoSAR). The basic idea is to operate at least two physically separated receivers with a relative motion so that their azimuth (cross-range) separation varies with time. Pairs of echoes acquired at each instant of time and relative position can be combined to produce estimates of the spatial autocorrelation function of the received signal. Estimates of this autocorrelation function for different po- sitions can then be combined to high resolution images of some statistical properties of the scene, like, for example, the Normalized Radar Cross Section (NRCS) or the first Doppler moment. A possible mission concept using two geosynchronous spacecraft is analyzed.