A bioregenerative life-support garden (60 m² of tray area, modelled after MELiSSA/BLSS studies) grows five crop types, each with a real approximate yield density and energy content:
Wheat 0.20 kg/m²/day · 3390 kcal/kg
Soy 0.15 kg/m²/day · 1866 kcal/kg
Leafy greens 0.35 kg/m²/day · 150 kcal/kg
Sweet potato 0.45 kg/m²/day · 860 kcal/kg
Insect protein (cricket) 0.60 kg/m²/day · 1210 kcal/kg
Insect protein is by far the most area-efficient calorie source in closed-loop habitat studies, but it is excluded by three of the four modelled cultural/dietary groups (vegetarian, halal, kosher) — only the "no-restriction" group can eat it. This is the core tension the sliders expose: pushing insect-tray area up raises total calories but can leave minority-diet crew members short, even while the aggregate looks fine.
kcal(crop) = yield(kg/m²/day) × area(m²) × kcal/kg
required(group) = crew_count(group) × 2500 kcal/day
coverage(group) = compliant_kcal(group) / required(group)
O2(kg/day) = 1.46 × Σ biomass(kg/day) − 0.84 × crew_size
- Crew size / diversity — sets how many astronauts follow each of the four diet groups (omnivore, vegetarian, halal, kosher); the non-omnivore share is split evenly across the three restricted groups.
- Insect / soy tray sliders — reallocate growing area; the remainder always splits evenly across wheat, greens and sweet potato so total tray area stays fixed at 60 m².
- Total coverage — all food energy grown, against the whole crew's need, capped at 150% for display.
- Worst-served group — the lowest per-group coverage among groups that actually have crew in them; this is the equity signal a purely aggregate number hides.
- Net O₂ balance — uses a 1.46 kg-O₂-per-kg-dry-biomass photosynthetic yield (from typical plant/algae photosynthetic quotients) against a 0.84 kg/day-per-astronaut respiration demand.
Real-world relevance: NASA and ESA long-duration mission studies flag food acceptability and cultural/religious dietary compatibility as a real risk to crew nutrition and morale on international, multi-national crews — a garden that is efficient on paper can still fail specific crew members if its crop mix ignores who is actually eating from it.