What went wrong with Apollo 13?

On April 11, 1970, at 7.13pm (US time), Apollo 13 was launched from the Kennedy Space Centre in Florida. Only two days later its crew, Commander James A. Lovell Jr, Command Module Pilot, John L Swigert Jr and Lunar Module Pilot, Fred W Haise Jr (pictured above, left to right), found themselves abandoning their planned landing of the module on the Moon, however, when an oxygen tank exploded.
Blowing out the side of the Service Module, the crew were left with only the Command Module and a series of life-threatening consequences. Suddenly they only had limited power, had lost the cabin heating system, and very soon they began to run out of water and food. Meanwhile, urgent repairs were needed to the carbon dioxide removal system, which threatened to flood the module with toxic fumes.

With a calmness that can only be marvelled at, Swigert and Lovell radioed Mission Control with the well known words, “Houston, we’ve got a problem.” Mission Control, led by flight director Gene Kranz, immediately switched its prime mission from exploration to getting all three crewmen back to Earth alive. Their first move was to shut down all essential systems. Even with this done however, there were only enough resources to keep two of them alive for two days; somehow they had to make them last four days – and then for all three men.

Mission Control worked hard on ways to get the lunar module’s filter system working to ensure the astronauts didn’t die of carbon monoxide poisoning by having the crew construct a makeshift system constructed from whatever they had to hand- in this case, duct tape, hosing and the command module’s surviving canisters; adapting them for lunar module use. They then had to make sure that the module remained in the Moon’s gravitation pull, so that as they travelled around it they would gain enough momentum to be powered back to Earth. Despite suffering from the cold of their situation, and a lack of food and water, the crew still managed to jettison the Service Module and fly the Command Module back into Earth’s orbit. They survived against all odds and eventually splashed down in the Pacific on April 17th.

Once the crew were safely on Earth, investigations began into what had gone wrong. It was discovered that a heating wire inside the liquid oxygen tank had lost its insulation and that as a result it gradually overheated – leading to an explosion the crew likened to a bomb going off.

Further work led to the conclusion that the initial design of the oxygen tank had played a part in the disaster. All the previous Apollo missions had flown without any oxygen tank problems but the tank on Apollo 13 had a troublesome history. As Space.com explains, “In October 1968, the Number 2 tank eventually used on Apollo 13 was at the North American Aviation plant in Downey, California. There, technicians who were handling the tank accidentally dropped it about two inches. After testing the tank, they concluded the incident hadn’t caused any detectable damage. The dropped tank was eventually cleared for flight and installed in Apollo 13. The tank passed all of its routine pre-launch tests. But at the end of March 1970, after a practice session called the Countdown Demonstration Test, ground crews tried to empty the tank — and couldn’t. “

The technicians “fixed” the problem by turning on heaters inside the tank to warm up the remaining liquid oxygen, turning it into gas which could then be vented to safety. The thermostat inside the tank was supposed to prevent the temperature from exceeding 80 degrees Fahrenheit. However, a surge of electricity caused the thermostat to weld shut without the technicians noticing. This meant that the continual intense heat damage to the internal wiring of the tank turned it into a small bomb, which was ignited when Apollo 13’s crew turned on the cooling fans inside the service module’s two liquid-oxygen tanks.

The Apollo 13 crew were all awarded the Presidential Medal of Freedom for their acts of heroism. Their story has been told many times, but most famously- and most accurately – in 1994 by Commander Lovell himself, who wrote about the mission in his book, Lost Moon. Such was the popularity of the book that director Ron Howard adapted it into the award winning film, Apollo 13, in 1995.