The modularized equipment stowage assembly (MESA) was a drawer in the base of the lunar module descent stage which stored equipment and supplies.
The modularized equipment stowage assembly (MESA) is located on quad 4 of the descent stage. It is deployed by the extravehicular astronaut when the LM is on the lunar surface. The MESA contains fresh PLSS batteries and LiOH cartridges, a TV camera, tripod, cable, tools for obtaining lunar geological samples, containers in which to store the samples, and other scientific devices. It contains a folding work table that also serves as a bracket on which the equipment transfer bag, used to transfer the PLSS batteries and LiOH cartridges to the cabin, is hung.
Apollo Operations Handbook: Lunar Module volume 1, section 2.11.8
During Apollo 13, an explosion in the service module caused the command module to lose electrical power. This required using the environmental control system of the lunar module to remove carbon dioxide from the air. However, the LM contained only enough LiOH canisters to remove the CO$_2$ of two astronauts for two days, rather than three astronauts for four days. There were square LiOH canisters from CM, but they did not fit into the holes for the round LM LiOH canisters, and an adapter from materials on-hand was infamously made.
Did Apollo 13 have additional LiOH canisters outside in the MESA that could have been used to scrub the air instead of adapting the CM canisters?
- Could the Apollo 13 crew have survived the CO2 issue using their spacesuits
- Why did Apollo 13 need to scrub the air in the LM?
- What did the Apollo missions do with old LiOH canisters & the water they produced?
- Were the Apollo CO₂ scrubber canister designs unified after Apollo 13?
This question is part of a series honoring the 50th anniversary of Apollo 13, "NASA's finest hour".