First aircraft, unmanned and powered by liquid hydrogen
According to Official Guinness Records,
The first Unmanned Aerial Vehicle (UAV) powered by liquid hydrogen is the Global Observer UAV, a 15-m (50-ft) wingspan prototype of which successfully flew at the US Army's Yuma Proving Grounds in Arizona, on 26 May 2005;results of which were announced at the Association for Unmanned Vehicle Systems International (AUVSI) Unmanned Systems North America Conference in June 2005. The Global Observer UAV will enable communications relay, remote sensing for military and commercial missions. It uses fuel-cell-powered electric motors to drive eight propellers. It is reported that it is able to store enough energy to keep it airborne through the night and can, therefore, remain in operation at altitudes of up to 19,810 m (65,000 ft) for longer than a week at a time.