CO2 Scrubbing Calculator

Each crew member exhales roughly 1.0 kg of CO2 per day through normal metabolism, which this calculator converts to a volume (0.509 cubic meters of CO2 per kilogram at standard conditions) to estimate how quickly an unscrubbed habitat would drift from ambient outside air (about 400 ppm) up to your chosen maximum safe concentration — giving you the "hours to max CO2" figure that shows how little slack there is without active removal. The three scrubber technologies represent real trade-offs astronauts and engineers actually weigh. Lithium hydroxide (LiOH) canisters are simple and lightweight (just 50 kg of hardware) but consumable: each kilogram of LiOH absorbs only about 0.92 kg of CO2, so canisters must be resupplied continuously, making this option best for short missions where consumable mass is cheaper than complex hardware.

CDRA (Carbon Dioxide Removal Assembly) uses regenerable zeolite beds that can be cycled indefinitely with no consumables, at the cost of more hardware mass and continuous power draw that scales with crew size. The Sabatier reactor goes a step further, chemically converting CO2 and hydrogen into methane and water (CO2 + 4H2 → CH4 + 2H2O), recovering about 0.818 kg of water per kilogram of CO2 processed — valuable on long-duration missions where closing the water loop matters more than saving mass or power. There's no single "best" choice: LiOH minimizes upfront mass, CDRA minimizes consumables, and Sabatier maximizes resource recovery at the highest power and hardware cost.