Editor's Note: Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet. Following is the fourth of her updates on the effort as part of Scientific American.com's In-depth Report on "The Future of the Poles."

McMURDO STATION, ANTARCTICA--Ever since we first conceived of this project, the logistics have been complex. Now the pieces are beginning to converge on the center of Antarctica. Having been stalled in South America for over two weeks by weather and bureaucracy, the British Twin Otters finally landed on the gravel runway at the main British base on the peninsula. The surface traverse carrying the fuel for the southern camp and the heavy material for the camp has covered almost 400 miles across the very flat Ross Ice Shelf. Today we have our survey Twin Otter so we can begin to bolt equipment to the floor and the wings. But patience continues to be the name of the game. 

Far on the other side of the continent, the German Bassler (a slightly modernized version of the historic DC-3) is ready to begin moving material to the northern camp but is pinned down in a blizzard. The U.S. Air Force C-17 along with the fuel for the northern camp and my colleagues are stuck in New Zealand waiting for the weather to clear. The ski-equipped aircraft Twin Otter ready to move the camp staff to the high altitude southern camp was diverted to conduct a medi-vac from another project. 

Aircraft are both our scientific instrument and the backbone of the expedition logistical network. On this ice covered continent, there are several tricks that allow airplanes to operate. In some places along the edges like the British Rothera station there are gravel runways where aircraft with wheels can land, but these are few and far between. 

Here at McMurdo, engineers have embraced the many faces of the frozen water to make safe landing sites. Looking out the window of the science building, the annual sea ice is flat. This six- foot thick expanse of ice can be used as a runway for skied aircraft until just after Thanksgiving. By early December, the strengthening sun produces extensive melt ponds and the airport roads quickly turn to mush and the infrastructure must be moved to the south. By mid- December, there are penguins, seals and orcas swimming along the former runways. This temporary facility is expensive to build, but the sea ice is flat and strong so aircraft with wheels can easily land here. Due to the budgetary shortfalls from the high cost of fuel, there is no sea ice runway this season. 

Our science aircraft is at the oldest McMurdo facility, Willy Field, a fully functional snow-covered airport complete with a control tower. This airport rests on the 300-foot thick floating ice shelf – a piece of the Antarctic ice sheet that has gone afloat. Given the soft snow cover at Willy Field, only airplanes with skies can land here. The New York Air National Guard C-130 just returned from our camp in the interior after  dropping off a load of camp cargo, including the frames for the cloth-sided building where we will sleep. 

My colleagues arrived on Thanksgiving Day on the wheeled Air Force C-17. This runway is built on hard glacier ice that is meticulously groomed each year to ensure that it is the perfect surface for airplanes with wheels. A two-inch layer of packed snow protects the ice from the summer sun but is solid enough to support wheeled aircraft.

Snow and ice are the material of choice for Antarctic aircraft operations. With any luck,the weather will improve and more of the chess pieces will land on snow and ice moving us closer to collecting data. 

Dispatches from the Bottom of the Earth: An Antarctic Expedition in Search of Lost Mountains Encased in Ice

(Images courtesy of Beth Burton. Above, the twin otter outfitted with the magnetometer pod on the end of the wing. Below, Michael Studinger installing the pod on the wing.)