Shuttle Radar Topographic Mission, illustration. Launched on 11 February 2000, the STS-99 Shuttle Radar Topographic Mission (SRTM) was the most ambitious Earth mapping mission of its time. The Space Shuttle Endeavour orbited some 233 kilometres above the Earth. It used C-band and X-band outboard antennae, one located in the Shuttle bay and one on the end of a 60-metre deployable mast. The SRTM radar was able to penetrate clouds as well as provide its own illumination, independent of daylight, obtaining 3-dimensional topographic images of the world's surface up to the Arctic and Antarctic Circles. The mission completed 222 hours of continuous radar mapping.