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How practically meaningful is the efficiency delta even of 60% (i.e. small-stature female compared to large-stature male)? You need to take food with you and h

How practically meaningful is the efficiency delta even of 60% (i.e. small-stature female compared to large-stature male)? You need to take food with you and have a closed-loop air and water supply whatever the crew looks like, as well as engines, communications, engineering equipment, science payloads, etc, etc. How much does it cost to overspec the "metabolic system" by 60% in that context? Then again, making everything the size of a 1.5m person rather than for 1.9m people would save on a lot of structural material and therefore mass and fuel[1]. But then again again, how much of the size of the ship is dictated by the size of the crew and how much by other non-biological need? [1]: which is why chibi "aristo" robots take over in Saturn's Children by Charles Stross, as they're small and suitable for efficient space travel. Large robots may need limbs removed in order to afford transport.

CobaltFire 3y ago
That’s not a question with an easy answer. Every single gram that has to have delta-v applied will need more fuel, which needs more fuel, commonly known as “The tyranny of the rocket equation.” Maybe the crew metabolic efficiency drops the required resources to a level that one or more systems can change what tech they use (step change), pushing the weight even further? Without further information about what the systems evaluations are, what technologies this might allow the employment of, and a thousand other points of data there is no way to actually answer your question. EDIT: You added the part about vehicle sizing while I was replying, which is one of those thousands of data points. There are so many follow on effects it’s quite mind boggling.