Astronaut Jay Apt installed the Mechanics of Granular Materials (MGM) during Space Shuttle mission 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. The MGM experiments aboard the Space Shuttle used the microgravity of space to simulate this behavior under conditions that cannot be achieved in laboratory tests on Earth. MGM provided data 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 were flown on two Space Shuttle flights. The experiment was managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama.
Image credit: NASA