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Installing Mechanics of Gran
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| Name of Image |
Installing Mechanics of Granular Materials (MGM) Experiment Test Cell |
| Date of Image |
1996-09-18 |
| Full Description |
Astronaut Carl Walz installs Mechanics of Granular Materials (MGM) test cell on STS-79. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: NASA/John Space Center |
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STS-65 Mission Onboard Photo
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| Name of Image |
STS-65 Mission Onboard Photograph |
| Date of Image |
1994-07-01 |
| Full Description |
In this photograph, astronaut Carl Walz performs the Performance Assessment Workstation (PAWS) experiment at the flight deck of the Space Shuttle Orbiter Columbia during the STS-65 mission. Present day astronauts are subject to a variety of stresses during spaceflight. These include microgravity, physical isolation, confinement, lack of privacy, fatigue, and changing work/rest cycles. The purpose of this experiment is to determine the effects of microgravity upon thinking skills critical to the success of operational tasks in space. The principle objective is to distinguish between the effects of microgravity on specific information-processing skills affecting performance and those of fatigue caused by long work periods. To measure these skills, the investigators use a set of computerized performance tests called the Performance Assessment Workstation, which is based on current theoretical models of human performance. The tests were selected by analyzing tasks related to space missions and their hypothesized sensitivity to microgravity. Multiple subjective measures of cumulative fatigue and changing mood states are also included for interpreting performance data. |
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Space Walz
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Space Walz |
| Explanation |
Astronaut Carl Walz [ http://www.jsc.nasa.gov/Bios/htmlbios/walz.html ] waves at his colleagues from the aft end [ http://antwrp.gsfc.nasa.gov/apod/ap961130.html ] of the Space Shuttle Discovery's [ http://shuttle.nasa.gov/index.html/ ] payload bay. During this 1993 spacewalk [ http://images.jsc.nasa.gov/images/pao/STS51/10073382.htm ], Walz evaluated tools, tethers, and a foot restraint designed for use in a weightless environment [ http://www.sciam.com/1998/0998issue/0998white.html ] while orbiting Planet Earth [ http://www.hq.nasa.gov/office/pao/History/40thann/40home.htm ]. |
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