Life Support Mass Calculator
The consumables a crew needs for a mission — oxygen, water and food by the day — and how much recycling cuts what must be launched, with the mass per person-day and what it costs to lift.
A person uses about 0.
How the life support mass calculator works
A person uses about 0.84 kg of oxygen, 3.5 kg of water and 1.8 kg of food a day, packaging included: some six kilograms, or two tonnes a year. Without recycling a crew of four for six months needs over four tonnes; with water recovered at 90% and oxygen regenerated at half, it is well under two.
The rates are inputs because they are design choices — hygiene water especially — and the launch cost row is why every closed-loop kilogram is worth so much engineering.
Formula: mass = crew × days × Σ rateᵢ × (1 − recyclingᵢ)
Worked examples
| Inputs | Consumables to launch (kg) | Note |
|---|---|---|
| Four crew, six months | 2,220 | under two tonnes |
| No recycling | 5,305 | over five tonnes |
| A Mars mission | 16,654 | why closure matters |
FAQFrequently asked questions
How much does an astronaut consume?
About 0.84 kg of oxygen, 2.5 to 4 kg of water and 1.8 kg of food a day including packaging — roughly six kilograms, two tonnes a year.
What does the space station recycle?
Over 90% of its water, from humidity and urine, and about half its oxygen by electrolysing recovered water. Food is the stream nobody has closed.
Why is water the biggest item?
Because hygiene water dwarfs drinking water, and it is heavy. Recovery of 90% or better is what makes long missions launchable at all.
What margin should I carry?
Twenty per cent is a common reserve for a mission with resupply; a Mars mission with none might carry more, plus a separate contingency for a failed recycler.
Does this include the recycling hardware?
No — the equipment has its own mass, and the trade is that mass against the consumables it saves. For missions under a few months, tanks win; beyond a year, recyclers do.
Where these figures come from
- NIST — CODATA 2018 fundamental physical constants — G and the speed of light
- IAU 2015 Resolution B3 — nominal solar and planetary conversion constants — the astronomical unit, solar mass and planetary radii
- CSIRO Space and Astronomy — Australia's national science agency
Last checked: September 2026. Constants are CODATA 2018 (G, c) and IAU 2015 nominal values (solar and planetary parameters).