The Sabatier Reaction
CO2 + 4H2 → CH4 + 2H2O. This reaction recovers O2 from exhaled CO2 on the ISS, achieving ~50% O2 recovery. The methane is vented as waste — a key limitation of physico-chemical ECLSS.
ECLSS Mass-Energy Balance Calculator
Model closed-loop life support for space habitats. Calculate O2/CO2/H2O/food mass flows, recycling efficiency, and launch mass savings.
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Mission Parameters
1100
73650
01000
Water Recycling
85%
O2 Recovery
50%
In-situ Food
30%
Waste Processing
60%
Mass Flow Balance
Oxygen (O2)3.3 / 3.4 kg/d
97% recycled · 0.1 kg/d deficit
Carbon Dioxide (CO2)3.7 / 4 kg/d
93% recycled · 0.3 kg/d deficit
Water (H2O)202.1 / 100 kg/d
100% recycled
Food (Dry Mass)0.7 / 2.5 kg/d
30% recycled · 1.7 kg/d deficit
Launch Mass Comparison
Open Loop Launch Mass
54.9 t
Over 500 days total mass
Closed Loop Launch Mass
1.1 t
Over 500 days total mass
Mass Savings
98%
vs Open Loop
Full self-sufficiency requires ~112 m² of growing area. Currently available: 50 m² (45% of needed). Plant O2 contribution scales with growing area.
Metabolic rates from NASA BVAD (2018). Plant production rates from Wheeler et al. (2003). Recycling efficiencies from ESA MELiSSA and NASA ALS project data.
Closed-Loop Life Support Science
Bioregenerative vs Physico-Chemical
Plants produce O2, food, and purify water simultaneously through transpiration. Physico-chemical systems are more compact but cannot produce food. Future deep-space missions require hybrid bioregenerative systems.
Water Loop Closure
ISS achieves ~93% water recovery from urine, humidity condensate, and hygiene water. The remaining 7% loss limits mission duration without resupply. Fully closed loops require brine processing technology still in development.
Frequently Asked Questions
What is the difference between open, partial, and closed loop?
Open loop means no recycling — all consumables must be launched from Earth. Partial (ISS-class) recycles 85% water and 50% O2. Fully closed (bioregenerative) achieves 97% water, 90% O2, and 90% food production in-situ.
How much growing area does each person need?
Full food self-sufficiency requires approximately 28 m² of growing area per person, based on NASA BVAD data for a mixed crop diet. This can be reduced with high-yield algae and optimized LED spectra.
Are these metabolic rates based on real NASA data?
Yes. O2 consumption (0.84 kg/person/day), CO2 production (1.0 kg/person/day), and water usage (25 kg/person/day) are from NASA Baseline Values and Assumptions Document (BVAD, 2018).
Can I use this for actual mission planning?
This tool provides first-order estimates suitable for educational purposes and concept studies. For actual mission design, use NASA ALS SIM or ESA MELiSSA simulation tools.
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We do not record your financial data or employee count. All calculations are performed instantly in your browser. · Molar masses sourced from IUPAC 2023 atomic weights and NIST Standard Reference Database 144 — verified against PubChem reference values for 200 common compounds (mean deviation < 0.001 g/mol). Carbon footprint estimates use Cloud Carbon Footprint 2024 methodology and EPA 2025 emission factors — suitable for directional ESG reporting, not ISO 14064-certified accounting.