On 21 July 1961 Gus Grissom became America's second man in space and the third human ever to fly in space.
Grissom, one of the seven Mercury Astronauts, launched in the Liberty Bell 7 space capsule aboard a Redstone rocket.
15 minutes and 37 seconds after lift off, Liberty Bell 7 splashed down near its intended landing site in the Atlantic Ocean.
Watch brief video highlights of Grissom's flight.
A perfect flight. But drama was yet to come.
Two helicopters were standing buy to fish out the Liberty Bell 7 capsule and Grissom himself.
The capsule started sinking and Grissom had only seconds to escape. He did, but his spacesuit, designed to keep him afloat, had a valve left open and began to fill with water making it difficult for Grissom to stay afloat.
The first helicopter on the seen, piloted by Jim Lewis, was unaware Grissom was in trouble and continued with its task of trying to the space capsule out of the sea. Whist Jim Lewis battled the waves to lift the sinking capsule, mission control looked on helplessly, they could see from their camera footage that Grissom was struggling.
Assistant Flight Director Gene Kranz recalled mission control looking on helplessly and shouting "Forget the spacecraft, get Gus, get Gus, get Gus".
The first helicopter was forced to move on as a warning light indicated the helicopter's engine was just minutes from failing and Jim Lewis, its pilot, did not want to risk lifting Grissom to a deathtrap of a helicopter. Lewis flew away from the scene, leaving a second helicopter that was standing by to come to Grissom's rescue.
The second rescue helicopter moved in to rescue Grissom from drowning. The Liberty Bell 7 spacecraft was beyond recovery and sank to the bottom of the ocean.
Gus Grissom's dramatic recovery from the ocean. Image credit: NASA
After his successful sub-orbital flight, Grissom later joined the Gemini mission and on 23 March 1965 he served as the command pilot for the first flight of the Gemini program.
He was later selected to serve as command pilot on the first 3 man flight of the Apollo program.
On 27 January 1967, with a month to go before the first flight of the Apollo program, tragedy struck. Grissom and his Apollo 1 co-pilots Edward White and Roger Chafee were killed in a fire during testing of the Apollo capsule at the Kennedy Space Centre.