Simulating Martian surface at the bottom of the world
Posted: February 3, 2002

Dr. Nancy Chabot of Case Western Researve University with the Arkansas-Oklahoma Center for Space and Planetary Sciences radiation dosimetry experiment near the Darwin Glacier, Antarctica. Photo: University of Arkansas
An experiment designed by the Arkansas-Oklahoma Center for Space and Planetary Sciences, now in place on the polar plateau of Antarctica, may help interpret the recent history of Mars.

The experiment, built by professors Derek Sears and Paul Benoit, University of Arkansas, and Stephen McKeever, Oklahoma State University, is designed to measure the ability of ice to stop high-energy "cosmic rays," or protons traveling at high speeds. Cosmic rays occur in outer space, and penetrate the atmospheres of Earth and Mars. Rocks and soil stop cosmic rays as the protons crash into the atoms in the solids, releasing energy and storing some of that energy within the soil and rocks as luminescence. Researchers can measure this luminescence and determine the age of the object in question.

Up until now there has been little interest in gathering luminescence data for ice -- researchers usually use the technique to date pots and campfires in archaeology or to determine radiation exposure in laboratories. However, as scientists have learned more about the polar ice caps on Mars, their interest in dating ice has blossomed.

Antarctica provides an ideal environment for the luminescence experiment due to the presence of old, dense ice far from rock outcrops that could produce radiation. Antarctic ice, which flows at a slow rate, makes an Earth-based "lab" site that most closely resembles the polar ice caps found on Mars.

The experiment is part of a larger effort to produce a spacecraft instrument, called ODIN, to study the polar ice caps of Mars. The instrument used in Antarctica will date how long ice deposits have been stable by measuring the amount of radiation exposure they have experienced.

"The Antarctic case is really just a test case for Mars -- if we can work successfully with Antarctic ice, Mars shouldn't prove any more difficult," Benoit said.

The experiment was placed 1.5 meters into the ice near the Meteorite Hills on Dec.10, 2001, by a field party lead by Ralph Harvey from the Antarctic Search for Meteorites (ANSMET), sponsored by the National Science Foundation, and will return home with the expedition in early February.