ON the 27th day of their trek, as a dozen "black specks" of humanity crawled across Antarctica's vast white silence, Lou Albershardt heard a sound she'd never heard in two decades on the ice.

The cable powering her drill, a US$100,000 piece of equipment cutting through ice 92 meters below, snapped without warning and vanished down the dark, frigid borehole. "I felt my whole body drop," she said. "I couldn't believe it."

Her US-Norwegian scientific team was 800 kilometers from the South Pole, their starting point, and 1,500 kilometers short of Troll Research Station, their destination. They sat atop the 3-kilometer-high East Antarctica plateau, amid "diamond dust" clouds of ice crystals, with temperatures dropping below minus 20 degrees Celsius, the wind biting, and their most vital research tool, their deep-coring drill, lost - locked in an instant icy grip far beneath their feet.

The expedition faced a wrenching failure. Albershardt knew no one ever retrieved a drill from so deep a hole. "No way."

It was January 18 and the Norwegian-American Scientific Traverse of East Antarctica was already one of the longest research treks ever undertaken in one of the least-explored parts of the continent.

An ambitious effort to probe the planet's oldest, thickest ice sheet for clues to past climate, it was the first major scientific expedition across the Queen Maud Land region in a half-century. Its goal was to help science better understand how Antarctica and future climate might interact in an age of global warming, how much ice might melt into the sea, how high the oceans might rise.

The first leg was a two-month journey to the South Pole in the Southern Hemisphere summer of 2007-2008 from this Norwegian outpost in East Antarctica, 235 kilometers inland from the southern ocean.

Westerly

This summer, the 12-member crew, half veterans of the first leg, left the US South Pole station on December 23 for the return trip, following a more westerly route back north, creeping along, in their cherry-red snow tractors, at the speed of a lawn mower.

The new, Swedish-built tracked vehicles may have been slow, but the transport was "fabulous," said expedition leader Tom Neumann.

A century after explorers first reached the South Pole on skis and dogsleds, these 21st century scientists were crossing the forbidding icescape while working at laptops, linking to the Internet via satellite, eating three daily meals in one big, boxy, heated module, and sleeping in stacked bunks in another, all pulled along atop outsized skis.

"The whole concept was that we spend as little time as necessary on surviving and as much time as possible to do science," said Neumann, 35, a NASA geophysicist.

He had the team to do it - five Phds in glaciology and related fields, including Ted Scambos, 53, a leading US ice expert and member of nine previous Antarctic expeditions.

Their dedication, spending four months away from home, was self-evident. Dartmouth College's Zoe Courville, 31, Eskimo-like in her knowledge of ice, had been married for less than a month when she packed up and headed south last October. "I tend to get excited about snow, and people don't understand," she laughed. Luckily her groom did.

Just as crucial to the team's progress were its Norwegian nonscientists, from Ole Tveiten, the tall physician watching over them all, to Svein Henriksen, a compact, intense former Volvo truck repairman who followed a simple credo as expedition mechanic: "I never give up."

On Jananuary 18 it was Henriksen who saved the day - and the drill.

"Before I knew it, Svein was already working on a 'hook'," Albershardt recalled for a reporter after the team reached this station on February 21.

In his workshop, a small red module on skis, Henriksen, 40, fashioned a contraption from plate steel and bolts that leader Neumann likened to "an upside-down tulip." Spitting on it for luck, the mechanic lowered it into Albershardt's 10-centimeter-wide borehole, down 62 meters to where it found the tangled cable.

Swinging and yanking this hook, the team snared the cable, began hoisting it up, but then lost it down the hole again. Over 36 hours, they repeatedly hooked, then lost the cable, until they raised it to a 3.3-meter depth. It would go no higher.

They then dug deep into the snow, grabbed the cable and reattached it to Albershardt's winch. But the real prize remained stuck far below. To melt the borehole walls imprisoning the drill, they needed ethanol, and they had none.

Late that Thursday, four and a half days after the drill stuck, a Twin Otter airplane from the South Pole station landed on the ice to deliver 40 liters of ethanol. Henriksen now improvised a plastic bottle whose spout would open when it was lowered to the right depth and its cord was jerked, spilling the solvent around the drill. By Friday morning, they were lifting the drill, undamaged, from the hole.

The scientific caravan set off again, with "Lasse" in the lead and "Sembla" taking up the rear. The American ice expert Scambos had dubbed the four snow tractors with the names of early explorers' favorite sled dogs.

Driving Lasse, Stein Tronstad of the Norwegian Polar Institute monitored a radar mounted like a prow on his ice "ship," searching ahead in the blinding white landscape for crevasses, the deep fissures that wrecked earlier expeditions.

Far to the rear, towed along 100 meters behind Sembla in a black-painted, sun-heated wooden cabin on skis, British scientist Kirsty Langley, also of the Norwegian institute, tuned in the low-frequency deep radar trailing behind on a boom, measuring ice-sheet depth and the topography of East Antarctica's mountainous surface, 1.6 kilometers or more down through the ice.

Surveys by their five "lookdown" radars, besides profiling the underlying landscape, mapped ice layers between coring locations, without chemical detail but showing how layer thickness - and therefore accumulations - varied along the traverse route.

Warming

For now, the 2008-2009 Traverse may have helped answer another key question, whether temperatures are rising in East Antarctica. Preliminary data suggest "we may be seeing a slight warming the past 30 or 40 years," said Scambos, lead scientist at Colorado's US National Snow and Ice Data Center.w

That would upend a long-held belief that East Antarctica has cooled in recent decades. And that, in turn, would raise the prospect of more ice, someday, slipping into the sea, raising ocean levels worldwide.

Such conclusions await one, two or more years of analysis and publication, in those peer-reviewed journals whose gray columns discuss the meaning of work carried out, with some risk and great effort, in the field.

That effort, like Svein Henriksen's in the numbing cold of the plateau, isn't always evident in the dry prose of science, but this mechanic finds his satisfaction elsewhere.

"It's a great experience, when everything is going good and you're coming back with all the vehicles," he said. "It was good to turn off the key for the last time, and relax."