Japanese astronauts training in free fall. JAXA (Japan Aerospace Exploration Agency) astronauts training in free fall on a KC-135 aircraft flight. From left, the astronauts are: Satoshi Furukawa (born 1964), Akihiko Hoshide (born 1968), and Naoko Yamazaki (born 1970). They are part of NASA's 2004 class of astronaut candidates. The free fall flights involve flying the aircraft in a parabolic trajectory to simulate the free fall conditions found in Earth orbit. The aircraft interior is padded to prevent injuries. Each period of free fall lasts about 25 seconds, and each flight includes 40 to 80 parabolas. Photographed on 13 October 2004.