Buzz Aldrin has been evacuated to Christchurch from a tourist trip to the South Pole after suffering medical issues.
The famous astronaut, 86, was a guest of the White Desert tourism operator, who said in a statement that his condition deteriorated during the trip and the decision was made to evacuate him to the US McMurdo Base in Antarctica.
White Desert said in a statement Mr Aldrin is suffering from fluid in his lungs.
An emergency request was made by The Antarctic Company in the early hours of the morning for an "ailing visitor".
The International Association of Antarctic Tour Operators confirmed Aldrin's evacuation saying he was in a "stable' condition.
He was taken by ski-equipped LC-130 cargo plane from the South Pole to McMurdo Base.
Mr Aldrin was then transferred on a Safair flight to Christchurch, and landed about 4.25am New Zealand time.
He has been transferred by St John ambulance to Christchurch Hospital.
White Desert said in a statement that he is being treated with antibiotics and is in a stable condition, and in good spirits.
Mr Aldrin was the second man to walk on the Moon as part of the 1969 Apollo 11 crew.
Mr Aldrin has focused his time on supporting human colonization of Mars in recent years.