Research into the effects of space flight on humans often
requires that investigators employ human subjects. To accomplish
this task, the Human Test Subject Facility's (HTSF) primary
responsibility is to provide qualified test subjects for ground-based
research.
Human Test Subject Facility personnel maintain detailed tracking of each test
subject's participation in all studies, their blood volume
contributions, and any radiation exposure. To remain current
in the test subject pool, physicals are repeated on a yearly
basis. Subjects interested in participating in studies where
blood or blood products are collected also have HIV and Hepatitis
screens every 6 months.
Investigations using both male and female test subjects require approval by
the JSC Committee for the Protection of Human Subjects. Major
studies are presently focused on the effects of prolonged
head-down bedrest (see www.bedreststudy.com for further details)
and on the use of artificial gravity (human centrifugation)
as a potential countermeasure to the adverse effects of prolonged
bedrest. 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 arrhythmogenesis (using advanced electrocardiography),
orthostatic intolerance, immune deficits and deficits in
dynamic visual acuity.
Evaluating selected countermeasures to space adaptation, testing medical devices
and equipment, and training for microgravity exposure all
benefit from the ability to simulate microgravity without
leaving Earth's atmosphere are activities conducted as part
of the NASA
Reduced Gravity Program. NASA, having recently retired it's KC-135, now uses a C-9 similar to the commercial
passenger DC-9 aircraft [KC/C9-135 photos] to fly parabolic arcs producing episodes of weightlessness lasting 20-25 seconds.
A typical flight lasts 2 to 3 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 HTSF also provides support to university
and other student groups whose experiments have been selected
to fly aboard the C-9. With the increased frequency
of Space Shuttle missions 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.
C-9 and Other Microgravity Simulations Summary Report
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