Former astronaut Buzz Aldrin, the second man to walk on the moon, was evacuated Thursday from the South Pole for medical reasons, officials said.

Aldrin, 86, piloted the first lunar landing module to reach the surface of the moon in 1969. He followed Neil Armstrong out the door and into history.

The tour company White Desert issued a statement Thursday saying Aldrin was visiting the South Pole with other tourists when "his condition deteriorated." The group said Aldrin was flown with a physician to the McMurdo research station on Ross Island in Antarctica.

Aldrin was in stable condition, the statement said.

The National Science Foundation said it was providing a humanitarian medical evacuation. NSF said a ski-equipped LC-130 cargo plane flown the New York Air National Guard was handling details of the flight.

Before leaving for the South Pole, Aldrin tweeted Tuesday to almost 1 million followers: "South Pole here I come! #antarctica#WhiteDesert#GYATAntarctica"

Aldrin, an engineer and West Point graduate, joined NASA in 1963. He, Armstrong and Michael Collins made up the historic crew of Apollo 11 that rocketed from the Kennedy Space Center on July 16, 1969, bound for the moon. Five days later, Collins stayed aboard the command module while Armstrong and Aldrin took the module to the moon's surface.

The moonwalks were telecast live around the world to an incredulous TV audience.

Armstrong's iconic first words: "That's one small step for man, one giant leap for mankind."

Aldrin's lesser-known words: "Beautiful view."

Aldrin was awarded the Congressional Gold Medal in 2011. He's written nine books, including a children's book published last year Welcome to Mars: Making a Home on the Red Planet.

Aldrin remains "a tireless advocate for human space exploration," according to his own website.