An ailing Buzz Aldrin, the second man to walk on the moon, was evacuated from the South Pole to New Zealand where he was hospitalized and stable Thursday.

Aldrin, 86, was visiting Antarctica as a tourist when he fell ill. He was flown to Christchurch from McMurdo Station, a U.S. research center on the Antarctic coast.

Tour company White Desert said Aldrin has fluid in his lungs, but was responding well to antibiotics. He’ll remain hospitalized overnight for observation. His manager Christina Korp, who accompanied him, said he was in good spirits.

On Twitter, she said the past 24 hours had been grueling. She posted side-by-side photos of Aldrin — one on a stretcher giving a thumbs-up with a purple knit cap on his head, another in a hospital bed, on oxygen and with an IV in his left arm.

Aldrin and Neil Armstrong became the first men on the moon, on July 20, 1969. Armstrong died in 2012.

Just three weeks ago, Aldrin was at NASA’s Kennedy Space Center in Florida for the unveiling of a new astronaut exhibit. The ceremony coincided with the 50th anniversary of his launch with Jim Lovell on Gemini 12, the last of the two-man Gemini flights. Both were present and looked as energetic as usual.

“We wish Buzz a speedy recovery,” the London-based White Desert tour company said in a statement.