On 20 February 1962, John Glenn (1921-2016) became the fifth human to enter space. For his spaceflight Glenn, a US Marine Corps aviator was strapped into a tiny Mercury capsule (named Friendship 7) just as Alan Shepard and “Gus” Grissom, the two earlier US astronauts had been. There was a big difference for Glenn’s flight; Friendship 7 sat atop an Atlas rocket rather than the rather smaller Redstone used to launch the first two Mercury missions. They had been simple ballistic lobs, but Glenn was going all the way into orbit.

image of friendship7 launch

“Godspeed John Glenn”: A reminder of the days when NASA could send astronauts into orbit. (Image credit: NASA)


Watched by a TV audience of 100 million, the Atlas functioned beautifully and Glenn became the first American (and third human; Gagarin and Titov preceded him) in orbit. Glenn enjoyed both the view and the novel sensation of microgravity.  At one point he noticed through his tiny window that his craft was surrounded by a swarm of tiny glowing motes which he called “fireflies”, he reported them to Mission Control and was surprised by how interested the men on the ground were by this phenomenon.  There was a reason for this;  a warning light at Mission Control suggested that Friendship 7’s heat shield had come loose, possibly the fireflies were debris released by this failure. If the heatshield was indeed faulty, Glenn’s mission would end with his horrific death as his craft disintegrated around him.

Image of John Glenn 1962

Glenn looks every inch the space hero in this 1962 portrait. (Image credit: NASA)


When Glenn was eventually told about this threat he was instructed to retain rather than release the Mercury’s retrorocket pack as he reentered the atmosphere. This was a risky action but it was hoped that the retrorocket pack’s hefty metal retaining straps would hold the shield in place.  Glenn endured a frightening re-entry; the capsule violently shook as he watched white-hot shards of metal stream from the inferno mere centimetres behind him (a scene memorably recreated in the classic movie The Right Stuff – a movie which Glenn himself disliked).

image of mercury-capsule-interior

The small size of the Mercury spacecraft is apparent in this diagram. Note too the retrorocket pack just visible at the vehicle extreme rear. The door shown open on the spacecraft’s nose released a drogue parachute to slow the Mercury’s descent. (Image credit: NASA/Aerospace Projects Review)


As it turn out it was the warning light rather than the heatshield that was faulty (the fireflies’ exact origin remains mysterious), and Glenn splashed down safely. His flight lasted just under five hours. Glenn was celebrated as a national hero, and retired from NASA shortly after. Controversially Glenn opposed NASA’s intention to recruit female astronauts and publicly stated this. No female astronaut flew on a NASA mission until Sally Ride’s flight in 1983, by then Glenn had changed his position. After leaving NASA Glenn entered the world of politics and served as senator for Ohio from 1974 to 1995.

His astronaut career had a strange coda; in 1998 Glenn made a second space flight at the age of 77 when he flew on Space Shuttle Discovery (STS-95), ostensibly as part of an experiment to study the effects of space flight on the elderly. Glenn became the oldest person to go into space, a record unbroken to this day.


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