05-16-2019, 02:49 AM
This really does depend on the efficiency of the life support system, and whether the population is human or biont, or mechanical, or virtual.
A human gives of waste heat of around 100 watts, so we can assume that this is the minimum amount of energy used by the body in a second. To obtain this energy the human needs to digest food, which itself must be grown.
An optimistic NASA report here suggests that four people could be supported by a 'bioregenerative system' in space totalling 98m3. This is about 25 square metres each; assuming that the spaceship is in Earth orbit, we can times this by the solar constant to get 34000 watts of power collected by this area. This works out to be around 0.3% efficient- I would hope that mature OA life support systems would be more efficient, but taking this as a guide for near-future energy usage, it suggests that each human will need at least 34,000 joules per second just to live.
A human gives of waste heat of around 100 watts, so we can assume that this is the minimum amount of energy used by the body in a second. To obtain this energy the human needs to digest food, which itself must be grown.
An optimistic NASA report here suggests that four people could be supported by a 'bioregenerative system' in space totalling 98m3. This is about 25 square metres each; assuming that the spaceship is in Earth orbit, we can times this by the solar constant to get 34000 watts of power collected by this area. This works out to be around 0.3% efficient- I would hope that mature OA life support systems would be more efficient, but taking this as a guide for near-future energy usage, it suggests that each human will need at least 34,000 joules per second just to live.