The FAA has set several requirements for approval of UAVs to enter routine flight in civilian airspace. One of the requirments is full collision avoidance of both "cooperating" aircraft (those with transponders) and "uncooperating" aircraft (those without transponders). NASA has previously demonstrated UAVs that can avoid cooperating aircraft and this month completed a demonstration of a UAV with a Detect, See, and Avoid (DSA) system. The system was tested on a Proteus UAV and tested against transponderless aircraft ranging from an F-18 to a hot-air balloon.