Bioregenerative Life Support Calculator
Calculate food production, O2 output, and self-sufficiency from crop growing area in space habitats.
About this calculator
A bioregenerative life support system (BLSS) uses living plants to simultaneously produce food and oxygen while consuming the CO2 crew members exhale — closing part of the life support loop biologically instead of purely mechanically. This calculator assigns each candidate crop its own per-square-meter daily yield, calorie density, and oxygen output: lettuce grows fast but is calorie-poor (0.035 kg/m²/day at only 150 kcal/kg, mostly water), wheat is a calorie-dense staple (3,400 kcal/kg) at a slower growth rate, and soybean has the highest calorie density (4,460 kcal/kg, reflecting its protein and fat content) at the slowest yield of the three. All figures scale with a light factor benchmarked to 16 hours of grow-light exposure per day — cutting light hours proportionally reduces both food and oxygen output, since photosynthesis is light-limited in this model. Food self-sufficiency compares calories produced per crew member against a 2,500 kcal/day target, capped at 100%; oxygen self-sufficiency compares output against a 1.0 kg/person/day metabolic need.
Water consumption assumes roughly 5 liters per square meter per day for irrigation and transpiration. The calculator also back-solves the growing area needed to hit 100% caloric self-sufficiency for your crew size and chosen crop. The key limitation: a real BLSS blends multiple crops for nutritional balance and continuous harvest staggering, while this model assumes one crop and steady-state yield with no startup lag, disease loss, or the substantial power cost of the grow lights themselves.
Inputs
Results
Daily food produced (kg)
1
How to Use This Calculator
- Enter the number of crew members to support.
- Input the growing area (m²) dedicated to crops and the light hours provided per day.
- Select the primary crop — lettuce, wheat, or soybean — to set yield, calorie, and oxygen output rates.
- Review daily food produced, calories per person, and food self-sufficiency percentage.
- Check daily O2 produced, water needed, and the growing area required for full food self-sufficiency.
How the result changes with Growing area (m²)
| Growing area (m²) | Daily food produced (kg) |
|---|---|
| 25 | 0.5 |
| 38 | 0.76 |
| 75 | 1.5 |
| 125 | 2.5 |
What each input means
- Crew size
- Number of crew to feed.
- Growing area (m²)
- Total crop growing area.
- Light hours/day
- Hours of grow light per day.
- Primary crop (1-3)
- 1 = Lettuce (fast, low cal), 2 = Wheat (staple), 3 = Soybean (protein).
What each result means
- Daily food produced (kg)
- Edible food harvested per day.
- Calories per person/day
- Daily caloric contribution per crew member.
- Food self-sufficiency (%)
- Percentage of caloric needs met.
- O2 produced (kg/day)
- Oxygen generated by photosynthesis.
- Water needed (L/day)
- Daily water consumption by plants.
- Area for 100% food (m²)
- Growing area needed for full food self-sufficiency.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersCrew size = 6, Growing area (m²) = 50, Light hours/day = 16, Primary crop (1-3) = 2 = 4 input(s) provided
- Calculate Daily food producedDaily food produced1 = 1
- Calculate Calories per person/dayCalories per person/day567 = 567
- Calculate Food self-sufficiencyFood self-sufficiency23 = 23%
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does switching from lettuce to soybean change the food self-sufficiency percentage so much even though soybean yields fewer kilograms per square meter?
Self-sufficiency depends on calories produced, not kilograms — soybean's yield (0.015 kg/m²/day) is less than half of lettuce's (0.035 kg/m²/day), but its calorie density (4,460 kcal/kg) is nearly 30 times lettuce's (150 kcal/kg). Multiplying yield by calorie density, soybean delivers far more calories per square meter per day than lettuce despite the lower harvested mass.
What happens to food and oxygen output if I reduce grow-light hours from 16 to 8?
The light factor is grow-light hours divided by the 16-hour baseline, so dropping to 8 hours halves the light factor to 0.5, which directly halves both dailyFoodKg and dailyO2ProducedKg since the model treats photosynthesis output as strictly proportional to light exposure. Water consumption is calculated independently of the light factor, so it doesn't fall alongside food and oxygen output.
How does the calculator determine the growing area needed for 100% food self-sufficiency?
It back-solves from your crew size's total 2,500-kcal/person/day target divided by the selected crop's calorie density to get the required daily food mass, then divides that by the crop's yield-per-square-meter (adjusted for your light factor) to get the needed area. Because it uses the same single-crop, light-factor model as the rest of the calculator, this area figure inherits the same steady-state assumptions.
Does oxygen self-sufficiency above 100% mean the plants are producing more oxygen than the crew needs?
Yes — the calculator compares daily O2 produced against a 1.0 kg/person/day metabolic need, and unlike the food self-sufficiency figure, oxygen self-sufficiency isn't capped at 100%, so it can report values well above that when growing area is large relative to crew size. It doesn't, however, account for any of that surplus oxygen offsetting a separate CO2-scrubbing or oxygen-generation system's load.
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