(Keith Vanderlinde/National Science Foundation via Reuters) 
 
 A medical rescue plane took off from Amundsen-Scott research station at the South Pole Wednesday morning, en route to complete only the third evacuation during the dark Antarctic winter in the station's 60-year history.  Two sick workers were evacuated from the National Science Foundation's (NSF’s) Amundsen-Scott South Pole research station today and taken to the British Antarctic Survey’s Rothera station on the Antarctic Peninsula. NSF officials have not identified or released any information about the medical condition of the crew member, who is employed by Lockheed Martin Antarctic Support Contract (ASC). Falkner couldn't provide further details about the medical motivation behind the rescues for privacy reasons. The decision to evacuate someone is not made lightly because such a rescue operation is both dangerous and elaborate. Every February, after the scientists have left, a few dozen people hunker down to spend the long, dark austral winter at the Amundsen–Scott South Pole research station operated by the National Science Foundation (NSF). And in August 2011, when 58-year-old Renee-Nicole Douceur, winter manager at the station, suffered a stroke, NSF deemed it unsafe to send in a rescue plane. Two of these hardy, winter-proof bush planes, operated by Canadian polar service firm Kenn Borek, landed at the British-run Rothera research station on the Antarctic coast Monday, each of them carrying a pilot, a co-pilot, an engineer and a medic. The second was prepped for a journey and equipped with skis to allow it to land on snow and ice. In recent decades, Kenn Borek’s Twin Otters have conducted perhaps a handful of emergency rescues. ASC is the prime contract for operations and research support contractor to NSF for the U.S. Antarctic Program. The South Pole station has no tarmac, so the planes must land in the dark on compact snow.
– At least one worker is seriously ill at the US South Pole station, and because it is winter in Antarctica, it would be easier to reach the unidentified person if he or she were anywhere else on the planet—or even on the International Space Station. The worker is one of 48 people wintering at the National Science Foundation's Amundsen–Scott South Pole research station, and two planes have been sent from Canada to carry out a very unusual and risky rescue mission, reports Science. Only two other such rescues have been carried out in the 60 years the station has been operating and, until the evacuation of physician Ron Shemenski in 2001, it had been thought that the relentless cold and dark made it impossible to get people away from the South Pole in winter, reports the Washington Post. Shemenski had pancreatitis and the NSF feared he would die. Two Twin Otter bush planes, each with a pilot, a co-pilot, an engineer, and a medic, are carrying out the mission, with one plane remaining at a British research station on the Antarctic Peninsula in case crew from the first plane need to be rescued. They hope to carry out the rescue by the middle of next week. (You can track progress here.) "It's a 10-hour flight, and you only have 12 or 13 hours of fuel on board," pilot Sean Loutitt, who was chief pilot during the 2001 rescue mission, tells the Post. "You're monitoring the weather the whole time, but eventually you get to a point of no return. Then you're committed to the pole, no matter what." He also took part in a rescue in 2003, when a worker had a gall bladder infection. The currently ill worker's medical situation has not been specified. (In 2011, the NSF balked at sending a plane after the station's winter manager had a stroke.)