Apollo 13 Lunar Module

This interior view of the Apollo 13 Lunar Module, taken on April 17, 1970, shows the so-called mailbox, which was a jerry-rigged setup the Apollo 13 astronauts built so they could purge carbon dioxide from the Lunar Module using lithium hydroxide canisters from the command module. The "mailbox" was designed and tested on the ground at the Manned Spacecraft Center in an effort to help get the troubled crew back home safely.

Read more about the Apollo 13 mission here.