It is 3,200 miles from civilization, in the middle of a chill, pitch-dark, virtually uninhabited wilderness the size of the United States and Mexico combined. The South Pole is as far from help as any place on Earth.

Isolated for nine months with 40 other people enduring the winter at the National Science Foundation's tiny Amundsen-Scott South Pole Station, a 47-year-old woman about three weeks ago discovered a lump in her breast.

Extreme cold and darkness made it impossible to land aircraft at the station, so today the Air Force planned to send a C-141 Starlifter cargo jet on an emergency mission to airdrop medical supplies to treat the woman until a springtime flight can evacuate her in November.

Officials would not identify the woman, or give any details of her condition: "The individual appreciates the support and concern she's received from friends and colleagues and the efforts made on her behalf," the foundation said in a statement yesterday. "She has chosen privacy at this point in a very personal process."

The woman is an employee of Englewood, Colo.-based Antarctic Support Associates, a private company contracted to maintain the base facilities and provide services to researchers working there.

The Englewood firm would not describe her work or her condition, but spokeswoman Valerie Carroll said the woman had had an x-ray and a biopsy at the station's medical facility.

Communications with the station were limited by satellite availability, Carroll said. But after the woman found the lump, she and the station's lone doctor had conducted medical consultations in conference telephone calls and by e-mail with doctors "from all over the country."

Officials would not specify exactly what medical supplies will be airdropped, but Carroll said they will enable the doctor to treat a variety of conditions if necessary.

There are 19 support personnel wintering at the station, along with eight scientists and 14 construction workers involved in "South Pole Rebuild," a project to revamp the 1970s-era installation, Carroll said.

"It is essentially a skeleton crew that keeps the station running," added foundation spokesman Peter West. "If you own a rental property, you don't turn off the heat. They're doing some maintenance, and some technicians are assisting with experiments."

Those who spend the winter at the Pole are stuck there between February and October, when ice and snow blow over the runways, and extreme cold cripples aircraft hydraulics, West said. The temperature at the Pole was minus 82 degrees Fahrenheit at 5 p.m. yesterday, with 12 mph winds, according to the foundation's Office of Polar Programs.

Responding to a foundation request, the Air Force yesterday readied a relief flight to leave today from McChord Air Force Base in Tacoma, Wash., fly to Hickam Air Force Base in Hawaii to refuel, and then fly on to Christchurch, New Zealand, for a 36-hour rest stop.

Air Force Capt. Bill Barksdale, spokesman for the McChord-based 62nd Airlift Wing, said that--weather permitting--the C-141 Starlifter planned to leave Christchurch Monday, refuel in mid-air from an accompanying KC-10 tanker jet, make its airdrop and return to Christchurch. The final round trip is 6,400 miles long, and most of it will take place in the dead of the southern night.

"It's challenging weather overall," Barksdale said. He noted that the 62nd Airlift Wing had been making flights to the Pole for the "last few years," but never during winter, and never in the dark. Barksdale said the emergency flight would carry between 20 and 30 people, including double crew and navigators.

Still, noted West, although the emergency was "unusual and unfortunate," airdrops were "something done on a fairly routine basis" in the past, when the wintering researchers demanded fresh vegetables and mail. The Internet, e-mail and better management of foodstuffs had made the flights unnecessary in recent years.

The South Pole Station is a geodesic dome with an arch-like entrance that gives it the appearance of a half-submerged, outsize igloo. Tunnels and a walkway connect the dome to a large garage, which, along with a fuel storage facility, are the only other large structures at the station.

During the southern hemisphere's summer months from November to February, the station accommodates up to 200 people who are working on hundreds of experiments under the aegis of the foundation, which funds a variety of scientific research, West said. Support Associates provides everything from lab assistants to cooks and aircraft mechanics.

In the earliest parts of the summer, large C-130 propeller-driven Hercules air cargo planes and smaller DeHavilland Otters land at the station's airstrip for resupply and to ferry personnel in and out. As the summer deepens, however, the surface of the two-mile-thick ice cap turns slushy, and the planes use skis.

But when winter sets in, the airstrip shuts down. Anybody who spends the cold months must go through a thorough medical screening, West said, to minimize the chances of serious medical problems.

A doctor remains through the winter to treat people at the equivalent of a "level three trauma center," a fairly sophisticated facility of the type that serves a town of 20,000 to 50,000 people.

West said officials are confident that the airdrop will bring adequate treatment for the current patient "without an imminent threat to her life," and expressed confidence the Air Force could bring off the relief mission without trouble.

"Beyond the sort of drama inherent in Antarctica," West said, "the airdrop is the only way you can get anything there."