Every day a crew stays awake, each astronaut burns roughly the same food, water and oxygen a person needs on Earth — call it 8 kg/day/person of total consumables once packaging, hygiene water and metabolic overhead are folded in. Multiply that by crew size and transit time and it dominates a deep-space mission's launch mass.
Therapeutic torpor — mild, medically-induced hypothermia — pushes the body toward the same metabolic slowdown that lets hibernating mammals survive a whole winter on stored fat. Cooling the core by only a few degrees can cut oxygen and caloric demand dramatically, so a torpor pod's daily consumables draw falls toward a small monitoring overhead instead of a full active-crew ration. One crew member stays awake on duty to watch the life-support telemetry; the rest ride in pods.
rate_awake = crew · 8 kg/day
rate_torpor = 8 + (crew−1)·[1 + 7·(1 − 0.75·depth)] kg/day
mass(t) = rate · t_days
margin(%) = 100 − 70·depth^1.2·(months/9)
- Transit duration — simulated one-way Mars transit, months. Longer trips make the daily consumables rate matter more.
- Torpor depth — how deep the metabolic suppression is pushed. 0% is a fully awake crew (baseline); 100% is the deepest modelled suppression.
- Safety margin — deeper and longer torpor narrows the modelled physiological safety margin; the gauge crosses into the red zone once the combination gets risky.
*Illustrative only, at $20,000 per kilogram of interplanetary launch mass — a rough order-of-magnitude figure for comparing scenarios, not a mission cost estimate.