The oxygen tanks had originally been designed to run off the 28 volt DC power of the command and service modules. However, the tanks were redesigned to also run off the 65 volt DC ground power at Kennedy Space Center.

Apollo 13 (April 11–17, 1970) was the seventh crewed mission in the Apollo space program and the third meant to land on the Moon. The craft was launched from Kennedy Space Center on April 11, 1970, but the lunar landing was aborted after an oxygen tank in the service module (SM) failed two days into the mission.

Two of three batteries were near full 40-amp-hour strength, but the third only had about half that amount. On a normal reentry, they would require at least 70 to 80 amp hours, but no one wanted to cut it that close on a mission that had so much going against it.

Using only material available on the spacecraft, Mission Control workers began devising a mechanism that would provide more carbon dioxide buffering. The ultimate solution involved using a piece of cardboard, a plastic bag, a hose from a pressure suit, duct tape and a sock to connect the command module scrubbers.