NASA investigators utilize human subjects to better understand the effects of space flight on the human body. The mission of the Human Test Subject Facility is to provide qualified test subjects for ground-based research and the parabolic flight program. Wyle manages and oversees the activities of the Human Test Subject Facility. Wyle also coordinates and schedules NASA Reduced Gravity Program flights on the C-9 aircraft for life science investigators.
Potential subjects participate in an Air Force Class III Flight Physical to become medically qualified. Human Test Subject Facility personnel maintain detailed tracking of each test subject's participation in their flight physicals, all studies, their blood volume contributions, and any radiation exposure to ensure the subject's safety. To maintain active in the general test subject pool, each subject renews their physical annually and infectious disease screening is every six months.
Investigations using human test subjects require approval by the Johnson Space Center Committee for the Protection of Human Subjects. Major studies are presently focused on the effects of prolonged spaceflight by utilizing head-down bed rest position. This allows investigators to study the effects of microgravity on the ground. One such study uses human centrifugation to simulate artificial gravity as a potential countermeasure to adverse effects of prolonged bed rest, which simulates long space mission. Other studies employ exercise protocols using treadmills, resistance devices, and cycle ergometers. Still others examine mechanisms of postural and/or gait instability, motion sickness, cardiac arrhythmias (using advanced electrocardiography), orthostatic intolerance, immune deficits and deficits in dynamic visual acuity.
Evaluating potential countermeasures to space adaptation, testing medical devices, and evaluating microgravity exposure are all benefits of the NASA's Reduce Gravity Program, which allows the ability to simulate microgravity without leaving Earth's atmosphere.
NASA, having recently retired it's KC-135, now uses a C-9 similar to the commercial passenger DC-9 aircraft to fly parabolas, thus producing episodes of weightlessness lasting 20-25 seconds. A typical flight lasts two to three hours and consists of 30 to 40 parabolas. The C-9 also can provide short periods of lunar (1/6) and Martian (1/3) gravity. Over the last 35 years, approximately 100,000 parabolas have been flown in support of the Mercury, Gemini, Apollo, Skylab, Space Shuttle, and International Space Station programs. Test Subject Facility personnel coordinate schedules for the C-9 and perform flight physicals for the investigators conducting experiments aboard the aircraft.
The Human Test Subject Facility also provides support to university and other student groups whose experiments have been selected to fly aboard the C-9. With the goals of longer space, missions to Mars and the habitation of the International Space Station, the Reduced Gravity Program provides a truly ideal environment to test and evaluate space hardware and experimental procedures before launch.