An international mission in February 2000 to obtain the most complete and accurate high-resolution digital topographic database of the Earth. NASA and the National Imagery and Mapping Agency led the project. The SRTM was launched aboard the space shuttle Endeavour and accomplished its mission during ten days of operation, covering 80% of the Earth's land mass. The mission used radar interferometry, two radar images taken from slightly different locations so these differences can be calculated to show surface elevation or change. The main radar bounced pulses off the Earth that were received by two antennae, one in the shuttle payload bay and a second extended 60 m out of the bay. On 23 September 2014, the White House announced that the highest-resolution topographic data generated from the mission was to be released globally by late 2015.

http://www2.jpl.nasa.gov/srtm/ Regularly updated with images from the Shuttle Radar Topography Mission (SRTM) and synthetic views of the Earth created with data from the mission, this site has information about the SRTM, its radar instrument and radar interferometry, and its data products.