22 January 1967, Cape Canaveral, Florida

One of Nasa’s most celebrated astronauts, Lt Col Virgil ‘Gus’ Grissom was becoming increasingly frustrated with his latest mission. He had every reason to be angry.

A former fighter and test pilot, Grissom was the second American to launch into space (the third overall). In March 1965, he became the first astronaut to return to space as commander of Nasa’s new two-man Gemini spacecraft. A year later, he was selected as the first commander of Apollo – the spacecraft being designed to eventually take a crew to the lunar surface and return them safely to Earth.

If all went to plan, Grissom would be in line to lead a mission to the Moon. Right now, however, even getting Apollo 1 off the ground was proving a challenge.

“The flight had been plagued with problems,” says Gerry Griffin, a guidance navigation and control systems officer – later a flight director – for the Apollo missions. “When the Apollo 1 spacecraft was delivered to Cape Canaveral, it was not in a good shape and they had to do a lot of work to get it ready.”