yee@trident.arc.nasa.gov (Peter E. Yee) (01/25/91)
Sarah Keegan
Headquarters, Washington, D.C. January 24, 1991
(Phone: 202/453-2754)
Jane Hutchison
Ames Research Center, Mountain View, Calif.
(Phone: 415/604-4968)
RELEASE: 91-11
UNDERWATER TESTS GATHER DATA TO HELP SPACESUIT DESIGN
Scuba divers exercising on a unique underwater treadmill at
NASA's Ames Research Center, Mountain View, Calif., may help
scientists design better spacesuits for future astronauts working
on the Moon or Mars.
"We hope to answer the basic questions of how human movement
and energy consumption will differ in the reduced gravity on the
Moon and Mars," said the study's Principal Investigator Dava J.
Newman, a doctoral candidate in aeronautical and astronautical
engineering at the Massachusetts Institute of Technology.
Newman and Co-investigator Dr. Bruce Webbon of Ames's
Advanced Life Support Division also hope to learn at what speed
humans change from walking to running and how much the joints
move during various gaits. Another objective is to determine
what kind of gait is most effective in different gravity fields
and what energy expenditures are associated with those gaits.
Three men and three women, all certified scuba divers
between 20 and 40 years old, are participating in the tests
conducted on a treadmill designed by Newman for underwater use.
Each experiment run consists of six 30-minute sessions. The
first session is a control experiment conducted outside Ames's
Neutral Buoyancy Test Facility (NBTF). The NBTF is a water-
filled cylindrical tank 9 feet deep and 11 feet in diameter.
Because water immersion is an effective technique to
simulate reduced gravity, the remaining sessions take place
inside the NBTF. Five different gravity conditions, or "g's",
are simulated: zero g, one-sixth g, three-eighths g, two-thirds
g and 1 g (normal Earth gravity).
By varying the number and placement of ballast weights
distributed in seven regions on the diver's body, Newman can
change the diver's buoyancy and thus simulate various
gravitational conditions.
Each diver wears a commercial diving face mask. Air is
provided through a supply hose from a surface tank. Heart rate
data and measurements of carbon dioxide exhaled and oxygen
consumed by the diver indicate how hard the person is working
under a specific workload and gravity field.
During each test session, Newman controls treadmill speed
while the diver keeps pace with the treadmill belt. Each diver
exercises at levels corresponding to 10 percent, 40 percent and
70 percent of the maximum work he or she is able to perform as
measured by maximum oxygen consumption.
The treadmill is equipped with a platform that measures the
force of each step, from which vertical speed and duration of
each step can be calculated. The degree and amount of leg, arm
and torso movements are recorded on video.
"Because humans have evolved under the influence of normal
Earth gravity, their muscles and joints probably will respond
differently under partial gravity," Newman said. She hopes her
research will provide basic information about these differences.
Newman believes such information may directly impact the
design of advanced spacesuits and portable life support
systems. For example, designers need to know how much mobility
astronauts' spacesuits should have to let them work most
efficiently under various gravity forces.
The study, which is scheduled for completion this spring,
may lead to improved spacesuit thermal control systems by
providing a basic measure of energy expenditures under various
gravitational forces.
Newman's tests also may lead to development of a training
program to help astronauts simulate specific tasks and experience
partial gravity prior to space flight.
- end -
NOTE TO EDITORS: Still photographs and a video to accompany this
release are available by calling 202/453-8375.
Photos: B&W Color
91-H-48 91-HC-59