English: A NASA Douglas DC-9 (C-9B) reduced-gravity aircraft is featured in this image during a parabolic flight photographed from a T-38 aircraft. The aircraft, based at Ellington Field near Johnson Space Center, flies a series of parabola patterns over the Gulf of Mexico to afford opportunities for astronauts and investigators to experience brief periods of weightlessness. The primary mission of the DC-9 is to provide NASA and government microgravity researchers the platform to perform their research in a reduced gravity environment. The aircraft is also utilized for Heavy Aircraft Training (HAT) for astronaut pilots, support the movement of the shuttle from landing sites in California and New Mexico back to Kennedy Space Center, Trans-Atlantic Landing support and the Emergency Mission Control Move mission.