On 20 February 1962 John Glenn became the first US astronaut to orbit Earth.
Launched from Cape Canaveral (Flordia) on an Atlas rocket, Glenn piloted the Mercury-Atlas 6 "Friendship 7" spacecraft for three orbits of Earth, reaching an orbital velocity of 17,500mph (approximately 28,000 kilometres per hour).
The mission time, from launch to impact, was four hours, 55 minutes and 23 seconds in space.
Glenn’s flight was cut short as mission control detected a problem with the spacecraft's heat shield. Fortunately, the heat shield stayed in place during the descent back to Earth.
Fred Jones, a retired Langley photographer, waited in anticipation to capture the historic landing on film, but unfortunately the capsule missed its predicted landing site, splashing down in the Atlantic Ocean 800 miles south east of Cape Canaveral - beyond the reach of Jones’ camera.
Glenn's orbital mission was the third space flight of the Mercury program.
Alan Shepard had been the first American in space with a sub-orbital flight on 5 May 1961, just a few weeks after Soviet Cosmonaut Yuri Gagarin had been the first human in space on 12 April 1961.
Shepard was followed by fellow Mercury Astronaut Gus Grissom whose sub-orbital space flight took place on 21 July 1961.
The Shepard and Grissom flights had been launched by the Redstone rocket, but another more powerful rocket was needed for NASA to achieve its next objective of reaching orbit.
Left: the Atlas rocket carrying the Friendship 7 capsule & John Glenn to America's first orbital spaceflight, 20 February 1962
The rocket that resulted in the NASA’s first manned orbital flight was the Atlas rocket.
Initial tests of the Atlas rocket were a little too dramatic compared to the reliable Redstone. "The very first time we saw a missile launch, it went up and blew up at 27,000 feet and that wasn't a confidence builder,” said Glenn.
The Atlas rocket was later perfected before Glenn’s flight.
When the day came more than 100 million people watched the Atlas rocket carry Glenn in his Friendship 7 capsule into orbit.
"The whole world was with me" recalled Glenn.
"Godspeed John Glenn" came the message from mission control as he was launched into space.
As Glenn completed his first orbit, a signal at mission control indicated the heat shield had come loose. Mission control asked him to leave the retro-package on during re-entry. Asked by Glenn if they could give a reason, mission control replied "Not at this time. This is the judgment of Cape flight". It transpired that the heat shield had not been loose after all; the malfunction was with a switch at mission control.
Glenn had a successful re-entry after three orbits and his place in American history, and that of human space flight, was assured.
There were three more Mercury missions after Glenn’s flight, and each one resulted in a lengthier space adventure than its predecessor.
"The whole program shifted rapidly from, 'Can we do this?' to basic research," said Glenn, who is now 90 years old.
Glenn returned to space aboard the Space Shuttle in 1998, mission STS-95.
He was aged 77 years at the time, making him the oldest person in space to date.
The Space Shuttle Discovery was a stark contrast to the tiny Friendship 7 capsule, as seven people could fit comfortably within the craft.
50 years after his Mercury flight and Glenn is still receiving praise.
"You could tell John Glenn to do anything and he'd do it right," said Bill Scallion, a retired NASA Langley researcher.
"There's a picture of him up on some pedestal waving in a spacesuit. Actually he was waving at me when I was leaving, after making him sit in that capsule in the trainer for four and a half hours."