FAYETTEVILLE - Julie Chittenden spent her four years as a doctoral student at the Arkansas Center for Space and Planetary Sciences at the University of Arkansas studying the effects of wind and soil on the stability of water and ice on Mars. Part of this research, dealing specifically with the effects of wind on Martian ice, won her the Geological Society of America's Stephen E. Dwornik student research award at the 2007 Lunar and Planetary Sciences Conference in Houston.
Chittenden's entire body of doctoral research suggests that water and water ice are more stable on Mars than previously thought. These findings are useful for missions to Mars and have implications for life on Mars.
"There's a mission being launched in August," she said. "It's going to the polar regions, and they're going to expose a layer of ice. So, because there's a lot of wind blowing in the polar regions, it's important to know how that's going to affect the ice when they expose it."
The Geological Society of America's planetary geology division awards only two Dwornik awards annually worldwide, one for an oral presentation and one for a poster presentation at the Lunar and Planetary Sciences Conference, which is the primary conference for the field of space and planetary sciences. Chittenden presented a poster titled "Effect of Wind on the Stability of Water Ice Under Martian Conditions." She joins the company of past recipients representing other premier research institutions, including the Massachusetts Institute of Technology, Brown University and Pennsylvania State University.
"My research also contributes to understanding about possible life on Mars because you have to have water for life," Chittenden said. "And, so this more stable water makes it more likely that life could form or biological molecules could form. So, it's part of the big picture: life on Mars or way, way later down the road if we send humans there for further exploration."
Prior assumptions of how water and ice would behave under Martian conditions were based on theoretical knowledge, such as mathematical modeling, and some research in laboratories. These results suggested that liquid water would immediately evaporate and water ice would immediately sublimate, or transition directly from a solid to a gas, when exposed on the surface of Mars due to atmospheric and temperature conditions on the planet.
What sets Chittenden's research apart from prior studies is that she conducted experiments in a chamber that mimicked the Martian environment, except for gravitational force, enabling her to accurately measure evaporation and sublimation rates of water and ice, respectively. She evacuated an airtight chamber, filled it with carbon dioxide, introduced a very low amount of atmospheric pressure (seven millibars) and reduced the temperature to zero degrees Celsius, thereby effectively simulating Martian conditions.
"We're among the first ones to actually do experiments that show what not just ice but also what liquid water does when it interacts with wind and soil," Chittenden explained.
"I think there are only a few groups that have hands-on labs, and those include groups at Caltech, some in Europe and here at the University of Arkansas," said Derek Sears, director of the Arkansas Center for Space and Planetary Sciences. "And, I think we're pretty much leading the way. If we're not the leader, we're certainly one of the leaders."
Chittenden's research consists of three components: the effect of brine formation on the stability of water, the effect of a soil layer on the sublimation rate of ice and the effect of wind on the sublimation rate of ice. She has shown that brine formation and the presence of a soil layer decrease evaporation and sublimation rates, thus making water and ice more stable. And, her final component showed that while wind increased sublimation rates of surface ice, the rate wasn't as rapid as previously thought because the wind cools the surface of the ice.
A native of Jonesboro, Ark., Chittenden graduated from Arkansas State University with a bachelor's degree in chemistry and is pursuing career opportunities at NASA.