“My question back to them is, By what standard is a stroke considered a nonemergency?” said Ms. Raines, who was raised by Ms. Douceur.

Ms. Raines has set up a Web site, Saverenee.org, and a Facebook page that urge people to call officials at Raytheon and the National Science Foundation. A petition at Whitehouse.gov has more than 700 signatures. Ms. Raines has enlisted the help of Senator Jeanne Shaheen, Democrat of New Hampshire, who wrote to the foundation.

“They’re saying the risk is too high,” said Ms. Douceur, who has worked at the South Pole on and off for three years. “But why aren’t you mobilizing and prepositioning planes so that when the weather breaks, you can come get me, instead of just saying, ‘No, you’re O.K., you’re going to wait’? It feels like they’re just stonewalling.”

Treating a stroke victim without access to imaging technology is difficult, said Dr. Walter J. Koroshetz, deputy director at the National Institute of Neurological Disorders and Stroke, because it is impossible to be sure what kind of stroke occurred. “If it’s a blockage of the blood vessel, the damage is done,” he said. But if the problem is a hemorrhaging vessel, more damage could still occur, “because that blood vessel is feeding brain that’s undamaged yet.”

Image Ms. Douceur, in green jacket, helps to unveil a new geographic marker for the South Pole on Jan 1, 2011.

The most famous instance of a person being airlifted from the South Pole for medical reasons was that involving Jerri Nielsen FitzGerald, a doctor who treated herself for breast cancer for months while stationed at the American research station. When she departed, on Oct. 16, 1999, it was the earliest in the Antarctic spring that a plane had taken off, according to The Antarctic Sun, a newspaper put out by the United States Antarctic Program, which is run by the National Science Foundation. She died in 2009 of a recurrence of breast cancer.

Temperatures must be higher than minus 50 degrees Fahrenheit for most planes to land at Amundsen-Scott or the fuel will turn to jelly. While that threshold has been crossed at the South Pole recently, the temperature still regularly dips to 70 degrees below zero.