Getting Ready for Europa
20 May 2003
(Source: NASA Astrobiology Institute)
NAI Europa Focus Group Visits Arctic Ice-Field
NASA Astrobiology Institute
In this special Feature, NAI Senior Scientist David Morrison recounts a recent trip to Barrow, Alaska with the Europa Focus Group.
In early May, the NAI Europa Focus group took a field trip to the Arctic Ocean ice cap at Barrow, Alaska. The trip was planned and led by Professors Ron Greeley of Arizona State University, the Chair of the Europa Focus Group, and Hajo Eicken of the University of Alaska, an expert on ocean ice and on the Barrow region. The conference's objective was to gain direct experience with sea ice and to look for possible analogues with Jupiter's moon Europa and other icy moons in the outer solar system.
Twenty scientists interested in Europa attended the Ice-Field Conference, covering disciplines primarily in geology, planetary science and microbiology. Three students were provided special funds from NAI to attend, and I went representing NAI Central. During our three days in Barrow, we spent two mornings in science sessions, made two trips onto the ice (one for a full day), chartered small planes to view ice features from above, and met with elders of the local Inupiat Eskimo culture.
At 72 degrees north latitude on Alaska's North Slope, Barrow is a very isolated community, reachable only by air except during the short summer when the ice breaks free. Barrow is the northern-most point in the U.S. There is no harbor. A Distant Early Warning radar and some modest research facilities are all that are left from a once substantial U.S. military presence during the cold war. In mid-May, the sun sets for only a couple of hours and the temperature rarely rises above freezing; indeed, the ocean ice is still forming. The Inupiat maintain some of their traditional lifestyle, but with the substitution of snow machines for dogs as a means of crossing the ice. At this season they are hunting the large bowhead whale, still using small skin boats, fur-lined sealskin parkas, and hand-thrown harpoons, in combination with GPS receivers and cell phones.
The ice fields themselves are awesome--a grand wilderness. I can best compare them (psychologically) to the Sahara desert, a windswept, trackless and constantly shifting landscape that seems to go on forever. We were all impressed by the variety of ice and the complex morphology on the ice flows. We traveled on the ice with snow machines (snowmobiles) and sledges--I spent much of my time standing on the back of a sledge holding tight as we negotiated smooth snow and rough ice. The newest ice is flat (and thin), but with age it fractures and builds up pressure ridges and hills several meters high, made of upended slabs of ice. In addition to traveling across the ice, we drilled several ice cores, of interest primarily to the biologists in our group. Even in this harsh environment, the bottoms of the cores were green with photosynthetic microbes. We were accompanied by local guides, who also carried guns to protect us from polar bears. We saw lots of bear tracks, but no actual bears (unfortunately).
For someone acclimated to the Mediterranean climate of California, dealing with cold itself was an interesting experience. When the wind blew, the chill factor was well below zero degrees Fahrenheit, and a facemask was necessary to keep skin protected. This is a polar desert with low precipitation rates, but the wind is continually redistributing the light, dry snow to make fantastic drifts and dunes.
Our flights gave us a complementary perspective. The two small planes swooped to within 100 meters of the surface and performed figure eights so we could see the interesting ice features in the Beaufort Sea northeast of Barrow.
We also were lucky to be addressed by two of the local elders, both of whom grew up in the traditional culture before World War 2. One had been a reindeer herder, the other a hunter and trapper--spending months alone in the wilderness. Today they are a valuable resource on changing conditions, where global warming is having major effects on the behavior of the Arctic sea ice. They told us that the ice is both thinner and less predictable than it was in previous decades.
While we learned a great deal about our own planet, we must be careful in applying this knowledge to icy moons such as Europa. There are superficial similarities, but the ice on Europa is thousands of times thicker and probably millions of years older than the sea ice near Barrow. Trip leader Ron Greeley noted that one purpose of this field trip was for us to see and experience the great complexity of Arctic sea ice, and thus to be more wary of making assumptions about other worlds based on gross appearances alone. Perhaps one thing we learned was humility.
You can get more information (and read a similar diary by Matt Pruis) at the Astrobiology Magazine's Europa Diary 1, Landing on Alien Terrain: http://nai.arc.nasa.gov/news_stories/news_detail.cfm?ID=257
More information on NAI's Focus Groups is available, including the Europa Focus Group: http://nai.arc.nasa.gov/institute/focus_groups.cfm