Saving Apollo 13 with a ‘Mailbox’
Apollo 13 was the third manned lunar-landing mission, part of Project Apollo under NASA in the United States. It launched on April 11, 1970 at 13:13 CST. Two days after the launch, the Apollo spacecraft was crippled by an explosion, caused by a fault in an oxygen tank. The explosion damaged the Service Module, resulting in a loss of oxygen and electrical power. The crew used the Lunar Module as a “lifeboat” in space.
To conserve energy, all but essential systems were shut down. The astronauts moved into the lunar module, which had enough resources for two days for two men. Now, those resources would have to last four days for three men. There was backup oxygen on board, but power and water had to be conserved. And carbon dioxide buildup would be a problem.
If the level of carbon dioxide got too high in the spacecraft, the crew would asphyxiate. Lithium hydroxide is a chemical compound that was used to remove carbon dioxide from the air in the spacecraft. There were plenty of lithium hydroxide canisters in the dead command module. The only problem was that the command module canisters would not fit in the lunar module’s environmental control system. A procedure had to be devised on Earth and relayed to the crew for adapting the square canisters for use in the lunar module.
Mission Control worked on the filter problem. The canisters of lithium hydroxide used to filter carbon dioxide in the lunar module were a different size from the available canisters in the command module. On directions from Houston, the crew rigged up a system using duct tape and hosing, to adapt the command module’s canisters for lunar module use. The contraption they built was called the “mailbox”.
The “mailbox” was a jerry-rigged arrangement which the Apollo 13 astronauts built to use the Command Module lithium hydroxide canisters to purge carbon dioxide from the Lunar Module. Lithium hydroxide is used to scrub CO2 from the spacecraft atmosphere. Since there was a limited amount of lithium hydroxide in the Lunar Module, this arrangement was rigged up using the canisters from the Command Module. The “mailbox” was designed and tested on the ground at the Manned Spacecraft Center before it was suggested to the problem-plagued Apollo 13 crewmen. Because of the explosion of an oxygen tank in the Service Module, the three astronauts had to use the Lunar Module as a “lifeboat.”
Despite great hardship caused by severe constraints on power, cabin heat, and potable water, the crew successfully returned to Earth. The mission was thus called a “Successful Failure”.
…I’m a space kid with a space dad.