Buzz Aldrin was medically evacuated from the South Pole on Thursday.

The 86-year-old astronaut was airlifted from the Amundsen-Scott South Pole Station to the McMurdo Station on the Antarctic Coast, according to a statement from the National Science Foundation.

The New York Air National Guard provided the “humanitarian medical evacuation flight.” Aldrin is awaiting a flight to New Zealand, but was reported stable when he left the South Pole.

Aldrin had been traveling with White Desert, a South African tourism firm, which sent the evacuation request for an “ailing visitor.” The details of his illness were not disclosed.

On Tuesday, Aldrin sent out a series of tweets over his excitement for the trip, including, “South Pole here I come!”

Aldrin was the second man to walk on the moon as part of the 1969 Apollo 11 mission.