As of November 2014, NASA has cancelled the Unmanned Aircraft Systems (UAS) Airspace Operations Challenge (AOC) due to unanticipated technical and operational issues as well as additional costs. NASA Centennial Challenges have historically been high-risk and leveraged activities conducted with minimal government funding. NASA reviewed the intended outcomes of the AOC and determined that the competition was no longer timely or cost-effective to execute as planned. NASA's cancellation of the AOC was not based in any way on technical progress or performance of the registered teams.