Reduced Gravity Program
- UNDER CONSTRUCTION -
The Reduced-Gravity Program operated by the NASA Lyndon B. Program Johnson Space Center (JSC) in Houston, Texas, provides the unique "weightless" or "zero-g" environment of space flight for test and training purposes on a cost-reimbursable funding basis. With the coming of age of the Space Transportation System and the current plans for the Space Station, this capability is ideal for the development and verification of space hardware prior to launch.
The Reduced-Gravity Program was started in 1959 to investigate human and hardware reactions to operating in a weightless environment. The reduced-gravity environment is obtained with a specially modified KC-1 35A turbojet transport which flies parabolic arcs to produce weightless periods of 20 to 25 seconds. The KC-1 35A can also provide short periods of lunar (1 /6) and Martian (1/3) gravity. Approximately 100,000 parabolas have been flown in support of the Mercury, Gemini, Apollo, Skylab, Space Shuttle, and Space Station programs.
The KC-1 35A cargo bay test area is approximately 60 feet long, 1 0 feet wide, and 7 feet high. The aircraft is equipped with electrical power, and overboard vent system, and photographic lights. Air and nitrogen sources are also available. Ground facilities include a test equipment build-up area, briefing room, and telephones.
A typical mission is 2 to 3 hours long and consists of 30 to 40 parabolas. These parabolas can be flown in succession or with short breaks between maneuvers to reconfigure test equipment. The Reduced-Gravity Office provides scheduling, test coordination, and in-flight direction for the test programs.
For additional information or the initiation of a project, contact:
NASA Lyndon B. Johnson Space Center
Reduced-Gravity Office, Ellington Field
Mail Code: CC43
Houston, TX 77058
Telephone (281) 244-9875
KC-135A Aircraft Trajectory
The above diagram shows a typical zero-g maneuver. However, the maneuver can be modified to provide any level of g-forces less then one g. Some typical g-levels used on different tests and the corresponding time for each maneuver are as follows:
| Negative-g (-0.1g) | Approximately 15 seconds
|
| Zero-g | Approximately 25 seconds
|
| Lunar-g (one-sixth g) | Approximately 30 seconds
|
| Martian-g (one-third g) | Approximately 40 seconds
|
Advantages of Testing in the Controlled
Reduced-Gravity Environment of the KC-135A
- Unlike a neutral buoyancy test, which simulates only a few of the dynamic aspects of zero-gravity, this facility provides a true three-dimensional "weightless" environment.
- Certification/qualification/crew training can be accomplished with flight hardware.
- The large test area allows the Principal Investigator (p.I.) to fly on the airplane with diagnostic and support equipment. The P.I.'s real-time and first hand observations are valuable during development of the hardware.
- An iterative-type design approach can be used because the capability exists to make changes between parabolic maneuvers.
- To prove concepts, baseline experimentation can be accomplished in the KC-135A rather than having to commit to the expense of space flight.
The Aircraft
Air Force KC-135A: A four-engine turbojet aircraft similar to the commercial Boeing 707
Crew: Pilot, copilot, flight engineer, and two test directors
- Electrical power available
- 28VDC, 80 amps
- 110VAC, 400 Hz, single phase, 50amps
- 110VAC, 400 Hz, three phase, 50 amps per phase
- 110VAC, 60 Hz, single phase, 20 amps
- Still and motion picture photography, video, as well as S-band video/data downlink
- Most test equipment to be bolted to the floor using 20-in. tiedown grid attachment points
- Vent/vacuum system to dump fluids overboard
- Liquid or gaseous nitrogen available
- Breathing air available
Cabin Cross-Section View
Floor Plan
Responsibilities:
Responsible NASA Official: John S. Yaniec (john.s.yaniec1@jsc.nasa.gov)
NASA Technical Monitor: Sharon Beth Halprin (sharon.b.halprin1@jsc.nasa.gov)
Webmaster: Long Trinh
Last Updated: November 1, 2006