Buzz Aldrin, the adventurer, the former astronaut and the second person to walk on the moon, was evacuated from Antarctica on Thursday after falling ill while visiting the South Pole with a tourism group.

The National Science Foundation said in a statement that it had provided a “humanitarian medical evacuation for an ailing visitor” from the Amundsen-Scott South Pole Station to McMurdo Station, the main research facility on the coast of Antarctica. The statement said Mr. Aldrin, 86, was then flown to Christchurch, New Zealand.

White Desert, the tourism operator, said in an email that Mr. Aldrin, who was taken to a hospital, “currently has fluid in his lungs but is responding well to antibiotics and being kept overnight for observation.” It described his condition as “stable” and said he was in “good spirits.”