Former astronaut Buzz Aldrin, the second man to step foot on the moon, was evacuated from the South Pole Thursday for medical attention.

The 86-year-old was vacationing in Antarctica at Amundsen-Scott South Pole Station with a group from luxury tourism operator White Desert when his health began to deteriorate, NPR reported.

He was to be airlifted to McMurdo Station in New Zealand the same day in a cargo plane dispatched by the National Science Foundation, according to a news release. Crews are reportedly working quickly to evacuate Aldrin, who was a part of the two-man lunar landing crew of Apollo 11 in 1969.

Aldrin's condition has not been disclosed. The foundation said it will provide updates later on Thursday.

Aldrin left for Antarctica on Nov. 29, and has posted updates about the adventure on his Twitter and Instagram accounts.

“South Pole here I come,” he tweeted as he boarded a plane in Cape Town, South Africa, earlier this week.