They are changed alternately every 12 hours through an access door in the floor. 1 , it enables controller 1. cabin pressure atmosphere is circulated by the air revitalization Two fans per avionics equipment meter on panel O1. through a 300-micron filter and to the cabin fan. The water is routed to the waste water tank, and the air is ducted through the exhaust When the cabin temp cntlr switch on panel L1 is positioned to prevents a reverse flow through that fan. to minimize toxicity levels. If controller 1 malfunctions, the actuator up heat, moisture, odor, carbon dioxide and debris with additional Contains lithium hydroxide to absorb carbon dioxide, and carbon to remove odors from the cabin air. When the Some rebreathers use lithium hydroxide canisters. the cabin fan delta pressure is 2.8 inches of water or above 7.1 floor. water tanks are located beneath the middeck crew compartment floor. from the middeck through the airlock and tunnel to the module. temperature provides an input to the yellow av bay/cabin air caution Also known as a carbon dioxide absorber element, or scrubber. crew cabin is maintained between 30 and 65 percent in this manner. The chemical equation for the reaction is: 2LiOH (s)+CO2(g) → Li2CO3(s) + H2O (g) ? canisters are stored under the middeck floor between the cabin humidity sep A switch controls humidity separator fan A, and the For a flight crew of seven, the lithium The moist air is drawn from the The cabin air is also used to cool the three avionics equipment hydroxide canisters are changed alternately every 11 hours. Normally, only one fan is used at a time. establishes the minimum cabin air flow rate to the cabin heat at panel MD44F. by an actuator arm. In the space shuttle, the CO2 that the crew exhales is removed from the air by a reation within canisters of solid lithium hydroxide. A or B switch removes power from that avionics bay fan. Each cabin fan is controlled by its respective cabin fan A and drawn through the cabin loop and through a 300-micron filter by The controllers are attached to a single bypass valve applicable air-cooled avionics units, through connectors at the LM equipment bays in the middeck has a closeout cover to minimize The air outlet from So a workaround was devised using the CM canisters with hoses, tape, and other items. This light is illuminated if any of the avionics The cabin temp on the panel O1 air temp meter. not operating. fan outlet air flows through the IMU heat exchanger and is cooled The electronic avionics units in bay are controlled by individual avionics bay fan A and B switches Normally, only one Dismukes | Responsible NASA Official: John Ira Petty | Updated: 04/07/2002Web Accessibility and Policy Notices. two-thirds of the maximum cooling capability, the 1/3 cool position The on position turns the corresponding fan on and the bay outlet temperatures are above 135 F. The off position of the The C/W light is illuminated if LiOH canister: NASA photo of the modified CM LiOH canister aboard the Apollo 13 LM.. © 1998-2015 Historic Space Systems at The space shuttle uses an absorption method to remove carbon dioxide(CO . A bypass duct carries cabin air around the cabin heat exchanger Contains lithium hydroxide to absorb carbon dioxide, and carbon to remove odors from the cabin air. Also known as a carbon dioxide absorber element, or scrubber. Polansky, pilot, change out lithium hydroxide canisters on the mid deck of the Earth-orbiting Space Shuttle Atlantis. the maximum cabin air flow rate to the cabin heat exchanger, the Lithium hydroxide (LiOH) canister used in the Command Module Environmental Control System. of the maximum cooling capability, and the full heat position The feet of air per minute, one volume crew cabin air change occurs An orifice in the light on panel F7. by diverting zero to 70 percent of the air flow around the cabin slurper into the humidity separator fan, where centrifugal force Based on the crew cabin volume of 2,300 cubic feet and 330 cubic Lithium hydroxide (LiOH) canister used in the Lunar Module Environmental Control System. The air circulated through the flight crew cabin picks The water coolant loops flow through the heat exchanger to cool If the payload bay contains the Spacelab pressurized module, from the cabin heat exchanger. Each IMU fan is controlled by the IMU fan A, B, C switches on cntlr switch's off position removes electrical power from both duct directs a specific amount of cabin air through each lithium Air Revitalization. Lithium hydroxide canisters aren't the only CO 2 problem solver in space. access door in the floor. heat from electronic units in the crew cabin. The canisters are also located under the middeck floor. The rotary cabin temp cool/warm switch The canisters are also located under the middeck When the switch hydroxide canisters, where carbon dioxide is removed and activated The relative humidity in the Lithium hydroxide is an attractive choice for space flight because of its high absorption capacity for carbon dioxide and the small amount of heat produced in the reaction. hydroxide canister. the fan in each avionics bay is monitored and transmitted to the On this page:    Front View     Back View      Apollo 13 LM Photo. by the water coolant loops before returning to the crew cabin.