Press Release

NASA’s Fifth Weightless Wonder to be retired

By SpaceRef Editor
October 25, 2004
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After a lifetime of ups and downs – 34,700 ups and downs to be exact – NASA’s last KC-135 aircraft, the “Weightless Wonder V,” will be retired Oct. 29.

The aircraft, the last operational KC-135A in the world, makes its final flight that day. It will be replaced by the “Weightless Wonder VI,” a C-9 aircraft acquired by NASA from the Navy to begin reduced gravity flights next year.

News media are invited to watch the KC-135A, designated NASA 931, as it returns from its final operational flight at 11 a.m. CDT, Friday, Oct. 29, to Ellington Field. The aircraft’s pilots and unique support crew will be available for interviews.

To attend the event, or to arrange phone interviews, contact the Johnson Space Center Newsroom at (281) 483-5111 by 5 p.m. CDT Thursday, Oct. 28.

KC-135A aircraft were used by the military for cargo and refueling. However, the NASA aircraft was modified for its special role. During nine years at Ellington, it has accumulated almost 2,000 hours of flight time, creating almost 200 hours of weightlessness, 20 seconds at a time.

The reduced-gravity environment is created by flying parabolic arcs – steep climbs and dives – to produce the 20 to 25 seconds of weightlessness. The flight maneuvers can be adapted to provide longer periods of simulated lunar gravity, one-sixth that of Earth, and Martian gravity, one-third that of Earth.

NASA’s Reduced Gravity Program began in 1957 at Wright Patterson Air Force Base. It investigates physiological and hardware reactions to operating in weightlessness. The operations moved to NASA and Houston in 1973. Including all aircraft used throughout the program at JSC so far, a total of almost 93,000 parabolas have been flown.

More than 2,000 college students have flown aboard the aircraft through the Reduced Gravity Student Flight Opportunities Program. They are provided an opportunity to design and conduct their own experiments in weightlessness.
In addition to its primary use as the “Weightless Wonder,” NASA 931 also has helped move the Space Shuttle fleet across the country, flying as an advance scout ahead of the Shuttle Carrier Aircraft 747 jet. It also has been used to transport many critical space hardware items, and has been on standby as a personnel transport in the event of Shuttle abort landings. NASA 931 played a key role as a transport during the Columbia accident recovery.

The new C-9 aircraft will be designated NASA 932. It is now undergoing modifications to prepare for service as the next “Weightless Wonder.”

Video of NASA 931 and highlights from its flights will air on the NASA Television Video File at 11 a.m. CDT Oct. 29.

NASA TV is available on the Internet and via satellite in the continental U.S. on AMC-6, Transponder 9C, C-Band, at 72 degrees west longitude. The frequency is 3880.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz. In Alaska and Hawaii, NASA TV is available on AMC-7, Transponder 18C, C-Band, at 137 degrees west longitude. The frequency is 4060.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz.

For more information about NASA’s Reduced Gravity Program, visit:

Still photographs of the KC-135 throughout its NASA history are available at:

For more on NASA, visit:

SpaceRef staff editor.