Neil Armstrong: Commander of the Apollo 11 mission and the first human to set foot on the moon. This was his second and last spaceflight. He also piloted Gemini 8 in which the rendezvous and first-ever docking between two spacecraft was successfully completed after 6.5 hours in orbit. Armstrong had a reputation for being very calm in dangerous situations and that may have played a role in him being selected as mission commander for Apollo 11.

He retired from NASA in 1971 and took up a post teaching engineering at the University of Cincinnati. He later became the chairman of electronic systems companies.

As well as retiring from NASA in 1971, he also retired from public life, only granting occasional interviews and rare appearances.

In the fall of 1979, Armstrong was working at his farm. As he jumped off of the back of his grain truck, his wedding ring caught in the wheel, tearing off the tip of his ring finger. He collected the severed digit and packed it in ice, and surgeons reattached it at the Jewish Hospital in Louisville, Kentucky.

After 1994, Armstrong refused all requests for autographs because he found that his signed items were selling for large amounts of money and that many forgeries were in circulation; any requests that were sent to him received a form letter in reply, saying that he had stopped signing.

Use of Armstrong's name, image, and famous quote caused him problems over the years. MTV wanted to use his quote for its now-famous ident depicting the Apollo 11 landing when it launched in 1981, but he declined. Armstrong sued Hallmark Cards in 1994 after they used his name and a recording of "one small step" quote in a Christmas ornament without permission. The lawsuit was settled out of court for an undisclosed amount of money which Armstrong donated to Purdue.

In May 2005, Armstrong became involved in an unusual legal battle with his barber of 20 years, Marx Sizemore. After cutting Armstrong's hair, Sizemore sold some of it to a collector for $3,000 without Armstrong's knowledge or permission. Armstrong threatened legal action unless the barber returned the hair or donated the proceeds to a charity of Armstrong's choosing. Sizemore, unable to get the hair back, decided to donate the proceeds to the charity of Armstrong's choice.

Neil Armstrong died on Aug. 25, 2012 at age 82.

Buzz Aldrin: Edwin "Buzz" Aldrin was the Lunar Module pilot for Apollo 11 and the second man on the moon.

Aldrin was the pilot on Gemini 12, the last Gemini mission and he used it to prove his methods for EVA. He set a record for extra-vehicular activity, demonstrating that astronauts could work outside spacecraft.

Aldrin, a Presbyterian, was the first person to hold a religious ceremony on the Moon. After landing on the Moon, he radioed Earth: "I'd like to take this opportunity to ask every person listening in, whoever and wherever they may be, to pause for a moment and contemplate the events of the past few hours, and to give thanks in his or her own way." He gave himself Communion on the surface of the Moon, but he kept it secret because of a lawsuit brought by atheist activist Madalyn Murray O'Hair over the reading of Genesis on Apollo 8.

The nickname "Buzz" originated in childhood: the younger of his two elder sisters mispronounced "brother" as "buzzer", and this was shortened to Buzz. Aldrin made it his legal first name in 1988.

He also left NASA in in 1971 and returned to the Air Force but his career was blighted by personal problems. His autobiographies Return To Earth, published in 1973, and Magnificent Desolation, published in June 2009, both provide accounts of his struggles with clinical depression and alcoholism in the years following his NASA career.

He has written several books including Men from Earth. He's a strong and vocal advocate for future U.S. manned space exploration and a frequent lecturer. Age: 82.

Michael Collins: He was the Command Module pilot on Apollo 11 and orbited the Moon while both Neil Armstrong and Buzz Aldrin made the landing.

His first flight was aboard Gemini 10. NASA staff meetings were always held on Fridays in the astronaut office and it was here that Collins found himself on January 27, 1967. Don Gregory was running the meeting in the absence of Alan Shepard and so it was he who answered the red phone to be informed that there was a fire in the Apollo 1 CM. When the enormity of the situation was ascertained, it fell on Collins to go the Chaffee household to tell Martha Chaffee that her husband was dead.

Since he would be the active participant in the rendezvous with the returning Lunar Module on Apollo 11, Collins compiled a book of 18 different rendezvous schemes for different scenarios including one where the Lunar Module did not land, or launched too early or too late. This book ran for 117 pages.

Apollo 11's famous mission patch was Collins' creation. Jim Lovell, the backup commander, mentioned the idea of eagles, a symbol of the United States. Collins liked the idea and found a photo in a National Geographic magazine, traced it and added the lunar surface below and Earth in the background. The idea of an olive branch, a symbol of peace, came from a computer expert at the simulators.

He exited NASA in 1970 and became the first director of the Smithsonian Institution's National Air and Space Museum in Washington. He wrote the book Carrying the Fire, which is considered to be one of the best insider space books. Age: 81.