What do a brick of vacuum-packed coffee, land under houses in San Francisco, powdered makeup, and tire tracks on Mars have in common?
They all behave according to laws of granular materials which we don't yet fully understand. To get a better grip on what happens when the ground shifts - under a house during an earthquake, or under the wheels of a rover exploring Mars - NASA this month will refly the Mechanics of Granular Materials (MGM) experiment to expand investigations started on STS-79 in 1996. On STS-89, scheduled for launch Jan. 22, MGM will run twice as many tests as it did in its first flight, and under a new range of experimental conditions.
The experiment was developed by NASA's Marshall Space Flight Center in Huntsville, Ala., and the University of Colorado in Boulder.
Knowledge from the MGM experiments will be applied in virtually any field that involves powders or granular materials, including the manufacture of pharmaceuticals and cosmetics, mining, land conservation and management, and planetary exploration.
While scientists have experimented with soil mechanics for decades, some aspects remain out of reach on Earth. The behavior of soils under low-confining pressures, where the soil acts like a liquid, is difficult to study under 1-g conditions on Earth. Under the low-g conditions of space, MGM provides a new range of test conditions, including conditions like those experienced by some soils during an earthquake.