For almost 56 hours after the launch of the Apollo 13 mission on April 11, 1970, it appeared to be the smoothest flight in NASA’s Apollo program to date.
The spacecraft carrying astronauts Jim Lovell, Jack Swigert and Fred Haise to their intended lunar landing had traveled just over 200,000 miles from Earth and was approaching the orbit of the moon.
Just before 9 p.m. on April 13, the crew completed a television program in which they circled the spacecraft and explained how they managed weightlessness. “It’s the Apollo 13 crew who wish everyone a good evening,” signed mission commander Lovell, a US Navy captain with three other missions (including Apollo 8).
Less than 10 minutes later, after a routine maintenance task that went wrong and blew up the spacecraft’s oxygen tanks, what was supposed to be the third moon landing of the US space program turned into a desperate race to save the lives of three astronauts. Working around the clock from Mission Control at the Manned Spacecraft Center (now Johnson Space Center) in Houston, Texas, flight controllers and NASA engineers improvised a series of innovative procedures to bring Lovell, Swigert and Haise home them safely on April 17, marking a successful conclusion to one of the most dramatic episodes in the history of the American space program.
Missed warning signs
In order to power the fuel cells that supplied most of the electricity used during the flight, the Apollo spacecraft carried two tanks of liquid hydrogen and two tanks of liquid oxygen. NASA’s subsequent investigation found that the No. 2 oxygen tank on board Apollo 13 was accidentally dropped during maintenance before the Apollo 10 mission in 1969, causing slight internal damage that did not appear during subsequent inspections.
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During the tests in March 1970, the reinstalled tank did not empty the oxygen properly. The test team decided to solve this problem by heating the tank overnight to force the liquid oxygen to burn. However, the overvoltage from the high voltage DC system on the ground caused the automatic shutdown switches on the tank water heater to fail and the temperature reached over 1,000 degrees Fahrenheit. Although there is no external indication of the problem, the heat apparently damaged the insulation of the wires inside the tank, turning the tank into a bomb waiting to explode.
Chain reaction leads to explosion
In flight, the astronauts had to periodically turn on the internal fans of the fuel tanks in order to stir the super cold oxygen, which tended to stratify or deposit in layers. But when Swigert activated the fans in the second oxygen tank for a routine cryo shaker on the night of April 13, the damaged wiring sparked, causing a fire. At 9:08 p.m., with its internal pressure assembly, the tank exploded.
As Lovell tells in a future HISTORY This week’s podcast, he and Haise were completely taken aback when they heard the blow. “I looked at Fred Haise to see if he knew what had caused the noise. And I could tell from his expression, he had no idea. Then I … looked down at Jack Swigert in the control module and his eyes were as wide as saucers. And I could see that … it was the start of a long and dangerous journey home. ”
“Houston, we had a problem here,” said Swigert, after noticing an illuminated light after hearing the sound of the exploding tank. (It would later be misquoted.) Additional flashing lights quickly indicated the loss of two of the ship’s three fuel cells, which, in addition to electricity, provided potable water, used to cool the ship’s systems. spaceship and hydrate astronauts.
Then, 13 minutes after the explosion, Lovell peeked out the window and saw something else disturbing. “We are venting something into … into space,” he said. “It’s a gas in a way.” Because the two oxygen tanks were located in the same segment of the spacecraft, the explosion had also damaged the other tank and it had started to leak oxygen into space.
The rocky road to touchdown
WATCH: Apollo 13 Emergency Radio Transmission
Houston ground controllers have now mobilized to carry out an unprecedented survival mission. They ordered the crew to proceed from the spacecraft control module, Odyssey, to the separate landing module, Aquarius. If things had gone as planned, Aquarius would only have been on when the astronauts were ready to land on the Moon. Now he had to keep Lovell, Swigert and Haise alive for about 90 hours, until they could return to the damaged control module to re-enter Earth’s atmosphere.
The crew deactivated all non-critical systems on board the spacecraft to reduce energy consumption and significantly reduce their water consumption, in order to have enough to cool the overloaded equipment of the landing module. At one point, when too much carbon dioxide accumulated in Aquarius, Mission Control designed a way for astronauts to empty the gas, asking them to build a “mailbox” out of plastic bags, cardboard and tape to purge the gas using cartridges from the control module.
“They developed a system and then passed it on to us word for word,” Lovell told HISTORY This Week. “Pipe. Tape and an old sock and my God, time was the only thing that kept us from dying.”
Apollo 13 declared a “successful failure”
On April 17, after Houston engineers successfully restarted Odyssey, the crew prepared for the final stages of their journey to Earth by abandoning the lunar module. Finally, at 11:53 a.m., what was left of the Apollo 13 spacecraft returned to Earth’s atmosphere, landing in the Pacific Ocean near Samoa.
Because so much valuable experience has been gained in the process of rescuing Lovell, Swiger and Haise, NASA has classified the Apollo 13 mission as “successful failure. “From Apollo 14, each spacecraft would be supplied with an additional battery as well as a third reserve oxygen tank, located in another section of the service module of the other two, which could be used exclusively to provide air to astronauts. Over eight other Apollo missions, no such incident has ever happened.
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