Consumable Limit
The Food Ceiling
You can recycle water and regenerate oxygen. Calories are a one-way trip. Every meal has to be launched from Earth.
The Formula
Total Food Demand
Calories/day × Crew × Days = Total
Nothing compresses this. Calories in, calories out — and calories only travel one way.
Per Person / Day
2,500 cal
The minimum for an active adult in a physically demanding environment. NASA's baseline is 2,500-3,000 kcal.
Food Mass / Person / Day
~1.3–1.8 kg (3–4 lb)
About 1.3-1.8 kg (3-4 lb) per person per day of packaged food, including packaging weight. Freeze-dried, vacuum-sealed, shelf-stable per NASA-STD-3001. Water for rehydration is separate.
Shelf Life
1-3 years
1-3 year shelf life at room temperature. NASA wants to push this to 5 years for deep-space missions, but current methods can't preserve nutritional quality that long. The calories stay, but the vitamins break down over time.
Scale Comparison
336 lb
210,000 total calories. Fits in a locker. This is also the only scale we've ever actually flown.
3.2 tons
4,050,000 calories. Needs a dedicated storage compartment. Eating the same food for six months starts wrecking morale.
36 tons
45,000,000 total calories. You need industrial-scale storage, you're fighting spoilage, and eating the same 20 meals for six months grinds down morale and health.
~110 tons
136,875,000 calories. At this scale, you can't launch the food — you have to grow it on site.
Why Food Is Different
Water can be recycled at 93-98% efficiency. Oxygen can be regenerated from CO2. But your body burns calories and turns them into heat and waste. There is no closed-loop food system that works at scale.
Every long-duration mission concept faces the same fork. Either you launch all the food from Earth, which means your payload capacity caps how long the mission can last, or you grow food in space. So far, growing food in space has only been done in tiny ISS experiments.
Of all the consumables, food has the hardest ceiling. It's probably the single biggest constraint on how long a mission can last, more than oxygen, water, or fuel. Whoever solves space-grown food solves the colony problem.