This NASA file image, dated July 20, 1969, shows one of the first footprints of Apollo 11 astronaut Edwin "Buzz" Aldrin on the moon. The Apollo 11 crew consisted of astronauts Neil Armstrong, who was the Mission Commander and the first man to step on the moon, Aldrin, who was the Lunar Module Pilot, and Michael Collins, who was the Command Module pilot. Apollo 11, launched forty years ago today on July 16, 1969, was the first manned mission to land on the moon. REUTERS/NASA/Handout
Astronauts Neil A. Armstrong, commander; Michael Collins, command module pilot; and Edwin E. Aldrin Jr., lunar module pilot, ride the special transport van over to Launch Complex 39A where their spacecraft awaited them in this NASA handout photo dated July 16, 1969. REUTERS/NASA/Handout
Apollo 11 crew's portrait session shows astronauts Neil A. Armstrong, Michael Collins and Edwin Aldrin in this July 1969 handout photo courtesy of NASA. REUTERS/NASA/Handout
NASA undated handout image shows a replica of the plaque which the Apollo 11 astronauts will leave behind on the moon in commemoration of the historic event. The plaque is made of stainless steel, measuring nine by seven and five-eighths inches, and one-sixteenth inch thick. The plaque will be attached to the ladder on the landing gear strut on the descent stage of the Apollo 11 Lunar Module (LM). Names include astronauts Michael Collins, Edwin Aldrin, Neil Armstrong and U.S. President Richard Nixon. REUTERS/NASA/Handout
The Saturn V rocket carrying the Apollo 11 spaceflight sits on the launch pad at the Kennedy Space Center on July 1, 1969 in this handout photo courtesy of NASA. Space enthusiast and entrepreneur Jeff Bezos has found the rocket motors used to send the Apollo 11 astronauts to the moon and plans to mount a recovery expedition soon, the Amazon.com CEO and founder reported on a blog post. The five F-1 engines were fired up on July 16, 1969, sending the massive Saturn 5 rocket on its way to the moon. The motors burned out a few minutes after liftoff from the Kennedy Space Center and tumbled into the Atlantic Ocean. REUTERS/NASA/Handout
Apollo 11 astronaut Neil Armstrong captures his shadow while taking a photo of the LM on the surface of the moon in this July 1969 handout photo courtesy of NASA. REUTERS/NASA/Handout
United States astronaut Buzz Aldrin stands beside a solar wind experiment next to the Lunar Module spacecraft on the surface of the Moon after he and fellow astronaut Neil Armstrong became the first men to land on the Moon during the Apollo 11 space mission July 20, 1969. July 20, 2012 marks the 43rd anniversary of the moon landing. REUTERS/Neil Armstrong/NASA/Handout
Spectators camp out before the launch of Apollo 11, near the Kennedy Space Center in Cape Canaveral, Florida, U.S., in this image from 1969. NASA/Handout via REUTERS
Astronaut Edwin E. Aldrin Jr., lunar module pilot, deploys a scientific research package on the surface of the moon near the Lunar Module (LM) "Eagle" during the Apollo 11 extravehicular activity (EVA) in this July 20, 1969 NASA handout photo. The photograph is one of more than 12,000 from NASA's archives recently aggregated on the Project Apollo Archive Flickr account. REUTERS/NASA/Handout via Reuters
Space communicators and astronauts Charles Duke, James Lovell and Fred Haise (L-R) stay in contact with the Apollo 11 astronauts during their lunar landing mission at mission control in Houston, Texas, July 20, 1969. NASA/Handout via REUTERS
The Apollo 11 crew, Neil Armstrong, Michael Collins and Buzz Aldrin, and U.S. Navy underwater demolition team swimmer Lieutenant Clancy Hatleberg wear biological isolation garments near the command module Columbia as they await pickup from the USS Hornet recovery ship in the Pacific Ocean about 812 nautical miles southwest of Hawaii, July 24, 1969. NASA/Handout via REUTERS
Apollo 11 astronauts Edwin E. Aldrin Jr., lunar module pilot; Neil A. Armstrong, commander; and Michael Collins, command module pilot pose at Johnson Space Center in this January 10, 1969 handout photo courtesy of NASA. REUTERS/NASA/Handout
This NASA file image shows U.S. astronaut Neil Armstrong, the Apollo 11 Mission Commander, standing next to the Lunar Module "Eagle" on the moon July 20, 1969. Apollo 11 was launched forty years ago today on July 16, 1969, and carried astronauts Armstrong, who was the first man to step on the moon, Edwin "Buzz" Aldrin, who was the Lunar Module Pilot, and Michael Collins, who was the Command Module pilot. Aldrin took this photograph. REUTERS/Edwin Aldrin-NASA/Handout
Apollo 11 astronauts Edwin Aldrin and Neil Armstrong have a pre-launch breakfast on July 16, 1969 in this NASA handout photo. REUTERS/NASA/Handout
Apollo 11 astronauts Neil Armstrong (L), Michael Collins and Buzz Aldrin smile through the window of the mobile quarantine van in this NASA handout image dated July 24, 1969. REUTERS/NASA/Handout
Astronaut Buzz Aldrin, lunar module pilot for Apollo 11, poses for a photograph beside the deployed United States flag during an extravehicular activity (EVA) on the moon, July 20, 1969. The lunar module (LM) is on the left, and the footprints of the astronauts are visible in the soil. Neil Armstrong/NASA/Handout via REUTERS
Computer scientist Margaret Hamilton (L) receives the Presidential Medal of Freedom from U.S. President Barack Obama during a ceremony in the East Room of the White House in Washington, U.S., November 22, 2016.
A television split-screen shot shows U.S. President Richard Nixon in the Oval Office speaking to the Apollo 11 astronauts on the moon (L) as Buzz Aldrin and Neil Armstrong walk on the lunar surface, July 20, 1969. Robert Knudsen/White House/U.S. National Archives and Records Administration/Handout via REUTERS
Apollo 11 astronaut Edwin E. Aldrin Jr. is strapped into his parachute harness during training at the U.S. Air Force Air Defense Command Life Support School, Perrin Air Force Base, Sherman, Texas in this undated handout photo courtesy of NASA. REUTERS/NASA/Handout
Apollo 11 astronaut Neil Armstrong waves to well wishers on the way out to the transfer van in this July 16, 1969 handout photo courtesy of NASA. Mike Collins, Buzz Aldrin and Deke Slayton (dark shirt behind Aldrin to the left) follow Armstrong down the hallway. REUTERS/NASA/Handout
Apollo 11 plaque, with the names of Neil Armstrong, Michael Collins, Edwin Aldrin and Richard Nixon, is seen on a strut of the lunar lander, on the surface of the moon in this July 1969 handout photo courtesy of NASA. REUTERS/NASA/Handout
U.S. President Richard Nixon watches the Apollo 11 moon landing on television and speaks to the astronauts live on national television from the Oval Office in the White House, Washington, U.S., July 20, 1969. The call from the White House was relayed by Mission Control to the astronauts via the Manned Space Flight Network (MSFN) antennas positioned around the world. Oliver F. Atkins/White House/U.S. National Archives and Records Administration/Handout via REUTERS
Astronaut Neil Armstrong, then the backup commander for the Apollo 9 mission and later the Apollo 11 commander, floats safely to the ground after ejecting from the Lunar Landing Research Vehicle (LLRV-1), which crashed during a simulated lunar landing at Ellington Air Force Base in Houston, Texas, U.S., May 6, 1968. Image taken from a 16 mm documentary motion picture recorded during the mishap. NASA/Handout via REUTERS
Astronaut Edwin E. Aldrin Jr., lunar module pilot, descends the steps of the Lunar Module (LM) ladder as he prepares to walk on the moon during the Apollo 11 mission in this July 20, 1969 NASA handout photo. REUTERS/NASA/Handout via Reuters TM3EBA90YAC01
The Apollo 11 Lunar Module ascent stage, with astronauts Neil A. Armstrong and Edwin E. Aldrin Jr. aboard, is photographed from the Command and Service Modules in lunar orbit in this July, 1969 file handout photo. Astronaut Michael Collins, command module pilot, remained with the Command/Service Module in lunar orbit while Armstrong and Aldrin explored the Moon. The 30th anniversary of the Apollo 11 mission is July 16 (launch) and July 20 (landing on the moon). Michael Collins/NASA/Handout via REUTERS
Looking through the window of a Mobile Quarantine Facility (MQF) are (L to R) astronauts Neil A. Armstrong, Edwin E. Aldrin Jr., and Michael Collins speak with their wives (L to R) Mrs. Pat Collins, Mrs. Jan Armstrong, and Mrs. Joan Aldrin at Ellington Air Force Base in this July 27, 1969 NASA handout photo. REUTERS/NASA/Handout
Astronaut Neil A. Armstrong, Apollo 11 commander, is pictured inside the Lunar Module (LM) while the LM rested on the lunar surface during the Apollo 11 mission in this July 20, 1969 NASA handout photo. The photograph is one of more than 12,000 from NASA's archives recently aggregated on the Project Apollo Archive Flickr account. REUTERS/NASA/Handout via Reuters
This NASA file image shows former President Lyndon Johnson (C), Lady Bird Johnson (third from left, center) and then Vice-President Spiro Agnew (second from right, center) at the July 16, 1969 launching of Apollo 11 at the Kennedy Space Center Launch Complex in Florida. Apollo 11, the first manned mission to land on the moon, was launched forty years ago today, and carried U.S. astronauts Neil Armstrong, who was the Mission Commander and the first man to step on the moon, Edwin "Buzz" Aldrin, who was the Lunar Module Pilot, and Michael Collins, who was the Command Module pilot.
Former U.S. President Richard M. Nixon welcomes the Apollo 11 astronauts aboard the U.S.S. Hornet in the Pacific Ocean in this July 1969 file photo. Already confined to the Mobile Quarantine Facility are, from left: Neil A. Armstrong, commander; Michael Collins, command module pilot; and Edwin E. Aldrin Jr., lunar module pilot. The 30th anniversary of the Apollo 11 mission is July 16 (launch) and July 20 (landing on the moon).
People celebrate as the Apollo 11 crew proceeds down Broadway and Park Avenue in a ticker tape parade in New York City, New York, U.S., August 13, 1969. Pictured in the lead car from right: astronauts Neil Armstrong, Michael Collins and Buzz Aldrin. NASA/Handout via REUTERS
This NASA file image shows Apollo 11 U.S. astronaut Buzz Aldrin standing on the Moon, next to the Lunar Module "Eagle" (R), July 20, 1969. Apollo 11 was launched forty years ago today on July 16, 1969, and carried astronauts Neil Armstrong, who was the Mission Commander and the first man to step on the Moon, Aldrin, who was the Lunar Module Pilot, and Michael Collins, who was the Command Module pilot. Armstrong took this photograph. REUTERS/Neil Armstrong-NASA/Handout
Apollo 11 lunar module pilot Buzz Aldrin, command module pilot Michael Collins and commander Neil Armstrong, seen in the lead car (L-R) are showered in ticker tape during a parade down Broadway and Park Avenue in New York City, New York, U.S., August 13, 1969. Bill Taub/NASA/Handout via REUTERS
A close-up view of the lunar rocks contained in the second Apollo 11 sample return container are shown in this undated file picture. The rock box was opened for the first time in the Vacuum Laboratory of the Manned Spacecraft Center's Lunar Receiving Laboratory, on August 5, 1969. The 30th anniversary of the Apollo 11 mission is July 16 (launch) and July 20 (landing on the moon).
50 years since the Apollo 11 moon landing