Astronaut Buzz Aldrin, 86, was flown from the South Pole Thursday after a private tourism firm requested a medical evacuation, the National Science Foundation said.
Aldrin, who became one of the first men to walk on the moon in 1969 during the Apollo 11 mission, was slated to be in the South Pole until Dec. 12, according to his website.
He posted a photo of himself on Twitter preparing to leave for the Antarctic trip on Tuesday.
Aldrin was traveling with White Desert, a private company that provides "luxury adventures in Antarctica," according to its website.
The NSF, which manages the U.S. Antarctic Program, agreed to provide a humanitarian medical evacuation from Amundsen-Scott South Pole Station to McMurdo Station on the Antarctic coast and then to New Zealand.
Aldrin was described as an "ailing visitor" by the NSF and information on his condition was not immediately available.