How NASA Deals With Odor Inside the International Space Station

Space may be a vacuum, but at least aboard the International Space Station, smells still have plenty of room to waft. And considering the ISS has 6 living, breathing, excreting human beings living in such close proximity, some of those smells could get to be a major problem. Fortunately, NASA's accounted for that.

NASA engineer Robert Frost and former ISS astronaut Clayton Anderson explain how NASA takes care of astronauts' more malodorous byproducts.

From Robert Frost, NASA Instructor/Engineer in the Mission Operation Directorate:

Odors can result from equipment off-gassing, crew metabolic processes, food, experiments, and returning EVA crew members. Two-hundred and sixteen such contaminants have been identified and designed for.

In the SM (Service Module), the Micropurification Unit () provides a regenerable means to remove both low and high molecular weight contaminants.

In the Lab, the Trace Contaminant Control Subassembly (TCCS) performs a similar function.

Both of these units are nominally operating. Either one is capable of providing the trace contaminant removal for the entire ISS. The vents contaminants overboard while the TCCS traps them in replaceable beds.

Major components of the TCCS include an activated charcoal bed, a catalytic oxidizer assembly, a lithium hydroxide sorbent bed, a fan, and a flow meter. Although the TCCS removes most atmospheric contaminants with the charcoal bed, the high temperature catalytic oxidizer is required for removal of lower molecular weight compounds, such as methane.

TCCS inlet air is drawn directly from the open cabin atmosphere into the activated charcoal bed by the TCCS fan, which is downstream of the charcoal bed. The charcoal bed is impregnated with phosphoric acid, which enables it to absorb ammonia. Downstream of the fan, the process air is split into two flow streams; one going to the Catalytic Oxidizer Assembly, and one to a bypass line. The flow rate to the Catalytic Oxidizer Assembly, measured by a flow meter, is used to control the speed of the fan to provide a specified rate of flow to the oxidizer. The remaining flow is sent through the bypass.

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How NASA Deals With Odor Inside the International Space Station