Flight manoeuvre in which the aircraft alternatingly ascends and descends to achieve weightlessness or to simulate reduced gravity.
Parabolic flights are performed to train astronauts in zero-g manoeuvres, giving them about 25 seconds of weightlessness out of 65 seconds of flight in each parabola. During such training, the airplane typically flies about 40–60 parabolic manoeuvres.
Initially, the aircraft climbs with a pitch angle of around 45 degrees, the sensation of weightlessness is achieved by reducing thrust and lowering the nose such that the aircraft follows a ballistic trajectory. Weightlessness begins while ascending and lasts all the way "up-and-over the hump", until the craft reaches a downward pitch angle of around 40 degrees.
Etymology:
from Ancient Greek παραβολικός /parabolikós/ “of or pertaining to a parable”
