It was 50 years ago this week that the world held its breath as three men battled for the lives in the depths of space.
April 11, 1970, at 13:13, Apollo 13 started its ascent from Cape Kennedy on its journey to the Moon.
Aboard was Jim Lovell, Jack Swigert, and Fred Haise.
Lovell was the mission commander, Swigert the Command Module pilot, and Haise would fly the Lunar Module.
At the 56 hour point, a simple command was issued from Mission Control.
The command was to “stir the cryo(genic) tanks)”.
At a distance of 290,000km from Earth, Swigert pressed the tabs that activated the mechanism.
About 90 seconds later a large bang was heard, and the dials showing electrical flow and operation of the attitude thrusters fluctuated wildly.
“Okay, Houston, we’ve had a problem here,” Swigert said.
The words were echoed shortly after by Lovell.
“Houston, we’ve had a problem. We’ve had a Main B Bus undervolt.”
From here on it became a battle for their lives, with ingenuity and a showcase of poor design and administrative decisions, working against each other.
The Command Module (CM) had lost two of its fuel cells; there are critical items and produced the electricity needed to make the CM work, and more importantly, provide heat for the humans inside.
A further issue arose, and one that had real potential to kill all three men.
In order to conserve power, the three had transferred to the Lunar Module, but it had been designed to hold two men — not three.
It was a delicate balance of usage versus consumption.
Their small and confined space required carbon dioxide scrubbers, and was slowly being overloaded by the extra CO2 being generated.
To add to the problem was the different design of the canisters fitted to the two modules.
In conjunction with a team on Earth, using plastic covers ripped from procedure manuals, duct tape, and other items, the Apollo 13 trio managed to jury rig a system that eventually started to lower CO2 levels.
The astronauts also had to cope, somehow, with a temperature that dropped as low as three degrees Celcius.
Lovell considered having all three wear their spacesuits, but was worried about overheating — so he decided to go the route of minimisation.
He and Haise would wear the EVA (extra vehicular activities) boots while Swigert had to resort to wearing a coverall.
Power consumption was a real problem as a certain amount of power was needed to fire the bolts that separated the two spacecraft components.
A second team at NASA, lead by Ken Mattingley, who had been due to go on the mission but fell ill shortly before launch, worked out a way of rerouting power and providing a way to do so without continually tripping the breakers.
The three also had to manually perform course corrections.
The guidance system was inoperative but it was vital they were on the correct course before separating the Lunar Module (LM) from the Command Module (CM), then separating the CM from the Command Service Module (CSM).
They had managed to separate the LM and CSM from the body of the CM, and it was at this point that they were able to see the damage and just how close to death the three had been.
The final part of the mission involved separating the CSM, the part that would make the journey from space to landing in the Pacific Ocean and it was here that NASA had reservations.
The concern was that the ablative plate, the section that would absorb heat and burn off as it travelled through the upper atmosphere, may have been damaged.
Much as the situation that claimed seven lives and the shuttle Columbia in 2003, where a damaged wing section allowed superheated air inside destroying the shuttle, any damage to this plate meant the module would fail and kill the three men.
After five days, 22 hours, and 54 minutes, the surviving section of the module named Odyssey completed a successful landing in the warm waters of the Pacific.
The men were retrieved by helicopter and transferred to the USS Iwo Jima, the designated recovery ship for the mission.
The next day they were flown to Hawaii, where then President Richard Nixon awarded them the USA’s highest civilian honour — the Presidential Medal Of Freedom.
Jack Gould, a writer with The New York Times, said later: “Apollo 13 which came so close to tragic disaster, in all probability united the world in mutual concern more fully than another successful landing on the Moon would have.”
Jim Lovell celebrated his 92nd birthday last month.
Fred Haise is also still alive, and will celebrate his 87th in November.
Jack Swigert, however, passed away in December, 1982, after succumbing to cancer.