Apollo 13 - 50th Anniversary

On April 11, 1970 - 50 years ago today - NASA launched a rocket from the Kennedy Space Center in Florida with three astronauts on board. This mission was labeled Apollo 13 and it was supposed to be the 3rd manned craft intended to land on the moon and explore the lunar surface. Sadly, due to mechanical failures, that plan was aborted.

Apollo 13 was commanded by naval aviator and engineer Captain Jim Lovell. The command module was piloted by aerospace engineer and test pilot Jack Swigert, while fighter-pilot Fred Hause would have been the lunar module pilot. (Swigert was originally backup to astronaut Ken Mattingly but Mattingly was grounded due to pre-flight exposure to rubella.) But the highly-trained crew never made it to the moon.

What happened?

Apollo 13 was plagued with several anomalies. First there were engine chamber oscillations. The hardware to stamp down oscillations existed but had not been installed on this rocket. The 2nd-stage engine shut down prematurely. Despite this, the spacecraft achieved the desired orbit around Earth, and then started on its course to the Moon. Three days into the mission, part way to the Moon, the mission control specialist in charge of the electrical systems detected a malfunctioning pressure sensor in a tank containing pure oxygen. These tanks were scheduled to be stirred once per day but he requested an additional manually-controlled stir, in the hope that this action would make the pressure reading more accurate. However, the insulation on the tank caught fire and was damaged during this operation.

The crew heard a large bang which they initially thought was from an impact with a meteoroid. Then the electrical power in the command module started fluctuating. Communications with Earth were lost for 1.8 seconds. Backup equipment automatically corrected for this loss and a few seconds later, Lowell, then Swigert, sent variations on the message which has become part of our cultural heritage:

"Houston, we've had a problem…"

The repercussions were severe: insufficient voltage from the power cells, antennas stopped working, fuel tanks lost pressure. The command module lost the oxygen necessary to maintain the life of the astronauts. Lovell reported seeing gas vented from the craft into space.

The astronauts were ordered to evacuate the command module and use the lunar module as a "lifeboat." The original goal of making a lunar landing was abandoned and the new, urgent goal was just to get the men back to Earth alive. This wasn't easy: the problems dominoed - the temperature fell to 38 degrees F and there was almost no drinking water. The astronauts had to jury-rig equipment to remove carbon dioxide from their air.

They suffered many more problems, but they did make it back, eventually splashing down into the South Pacific.

By AndrewBuck - Own work. Source for figures: Apollo 13 Mission Report, p. 3-2., CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=3820068

For more exciting details and to find out what happened next, try these ebooks: Apollo ebooks