NASA has a fleet of research aircraft carrying the latest sensor technologies that can be used for Earth observations. NASA's ER-2 aircraft, based at Armstrong Flight Research Center (AFRC) in Palmdale, California, flies as high as 70,000 feet (21,300 meters), almost twice as high as a commercial airliner, and is used for science research missions over much of the world. In December 2017, the aircraft flew locally over California wildfire events, testing early versions of science instruments that may one day be launched into space aboard a satellite to observe our home planet Earth.