Classification of matter from space

A non-transitory computer readable data storage comprising instructions which when implemented on one or more processors on a satellite cause the implementation of a method of earth observation, the method comprising:

• acquiring multiple synthetic aperture radar “SAR” images of a target area on the earth using a satellite travelling in a low earth orbit above the earth, wherein the data for each image is acquired from a different angle of incidence with respect to the target area and the different angles of incidence are 10° or more, wherein the acquiring comprises controlling an orientation of image acquisition apparatus on the satellite with respect to the target area to remain directed at the target area for a predetermined period as the satellite passes over the target area whereby to acquire the multiple images in a single pass of the satellite over the target area, the controlling the orientation of the image acquisition apparatus with respect to the target is achieved by controlling the orientation of the satellite with respect to the target area, and at least one of the different angles of incidence is generated forward and/or backward along a flight track of the satellite;
• for at least one pixel or pixel group in the images, analysing a variation of quantity of backscattered radiation with respect to angle of incidence;
• and
• using the analysis to identify matter imaged in the pixel or pixel group.