Apollo 11 launched this week in 1969, carrying the first men to land on the Moon. In the months leading up to the historic take-off, Nasa put the crew through gruelling, relentless simulations in order to prepare them – and BBC Tomorrow's World paid a visit.
"There's not much room in here, and these couches are very uncomfortable," said the BBC's John Parry as he sat suspended upside down, alongside James Burke, in the Apollo space capsule simulator at the Nasa space research centre in California in August 1968. "But it doesn't matter very much," he conceded, "because when you are in space your body doesn't weigh anything at all."
BBC Tomorrow's World had gone to see how Nasa was devoting vast sums of money and huge amounts of effort trying to mimic what the astronauts of Apollo 11 would see, hear and experience in space.
In 1962, President John F Kennedy had committed the US to the ambitious goal of landing a man on the Moon, and bringing him safely back to Earth.
Since then, the space agency had marshalled an extraordinary amount of people and technology, not to mention ingenuity and perseverance, to a project that would ultimately, in July 1969, propel astronauts Neil Armstrong, Buzz Aldrin and Michael Collins into space – and the history books.
To prepare those astronauts for this voyage into the unknown, Nasa had built a complex system of incredibly detailed simulators. These enabled the crew to master the intricacies of the Apollo spacecraft, and for Mission Control to meticulously rehearse every phase of the mission, from launch to lunar landing to re-entry.
The contraption Parry and Burke found themselves strapped into, recreated what it would be like to be inside and fly the command module which was nicknamed Columbia. Equipped with all the same flight controls and displays as the space capsule, it could generate all the responses and readouts that could happen on a mission. It was also designed to have exactly the same "feel" as the ones the astronauts would eventually use so they could develop their muscle memory.
"The spacemen who will be inside here may have to spend as much as 14 days locked up and for the whole of that time, they will take it in turns to do eight hour shifts at this control panel, looking at the dials and the instruments and controlling the switches," said Parry.
To create the feeling of being in space, Nasa had painstakingly created a 3D scale model of the Earth and an elaborate optical system that projected realistic out-the-window views as both the planet and the Apollo spacecraft rotated for each stage of the mission. The spaceship would need to rotate slowly in order to stop the Sun-facing side from overheating, and the other side freezing from the cold temperatures in space. The astronauts dubbed this manoeuvre "barbecue mode".
"Every minute motion of the spacecraft is reflected here, and as the prisms turn and roll the astronaut gets a vivid impression of the Earth hundreds of miles below him. Spain and the North African Coastline – it took six artists six months to paint on all the detail by hand, working mostly from satellite photos. Some of the areas on this map are accurate to half a mile," said Burke.
To allow the crew to determine the spacecraft's position and navigate their journey, another television camera projected realistic pictures of the stars in the sky that would be in their field of vision. "They roll gently past Apollo's window as the craft spins in deep space, 1353........