Automatic collision avoidance testing. US Air Force F-16D aircraft with Automatic Collision Avoidance Technology (ACAT) passing a Mojave Desert hill during a test flight. NASA's Dryden Flight Research Center is working with the Air Force Research Laboratory on the ACAT Fighter Risk Reduction Project to develop collision avoidance technologies that would reduce the risk of ground and mid-air collisions. Examples include the Automatic Ground Collision Avoidance System (Auto GCAS). The ACAT program began in 2004, with test flights from 2009, though earlier versions of the technology date back to the 1990s. Photographed on 24 March 2009.