American astronaut Buzz Aldrin was evacuated from Antarctica because he was showing signs of altitude sickness, he says.
American astronaut Buzz Aldrin - pictured in Christchurch Hospital in a photo posted to Twitter on Saturday Photo: Twitter / @Buzzs_xtina
The 86-year-old was visiting Antarctica as part of a tourist group when he fell ill.
In an update on his website, Mr Aldrin described how he started feeling sick during an excursion to the Amundsen-Scott Science Station, south of McMurdo Station.
"I started to feel a bit short of breath so the staff decided to check my vitals. After some examination they noticed congestion in my lungs and that my oxygen levels were low which indicated symptoms of altitude sickness.
"This prompted them to get me out on the next flight to McMurdo and once I was at sea level I began to feel much better."
His primary interest in going to Antarctica was because conditions there were more akin to Mars than anywhere else in the world.
"I didn't get as much time to spend with the scientists as I would have liked to discuss the research they're doing in relation to Mars. My visit was cut short and I had to leave after a couple of hours. I really enjoyed my short time in Antarctica and seeing what life could be like on Mars."
Mr Aldrin had been advised not to travel back to the United States yet, as he still had some congestion on his lungs. He remained resting at Christchurch Hospital.
"Thanks to everyone from around the world for their well wishes and support. I'm being very well looked after in Christchurch. I'm looking forward to getting home soon to spend Christmas with my family," he said.
The retired astronaut was part of Apollo 11, which was the first space trip to successfully send humans to the moon. He was accompanied by Neil Armstrong, who took the first steps on the moon - Mr Aldrin followed minutes later.
He has remained in the limelight in recent years, delivering cameo appearances in hit television shows such as The Big Bang Theory, The Simpsons and 30 Rock.
In 2002, he escaped assault charges after punching a man who demanded he swear on a Bible that the moon landing was not staged.
In recent years he has called for the colonisation of the planet Mars. In 2015, he told the BBC: "We'll lay out preparations up to that [going to Mars], in my mind we are doing it right now."
- RNZ / BBC