In this image from November 2010, the U.S. Air Force’s ACAT F-16D flew through Sierra Nevada canyons and past peaks during ground collision avoidance test flights. The ACAT, which stands for Automatic Collision Avoidance Technology, aircraft took off from Edwards Air Force Base on a flight originating from NASA’s Dryden Flight Research Center. Researchers at Dryden are working with the Air Force Research Laboratory in the ACAT Fighter Risk Reduction Project to develop collision avoidance technologies for fighter/attack aircraft that would reduce the risk of ground and mid-air collisions. Image Credit: NASA/Carla Thomas