I wonder what the marginal cost per crewmember is. On the one hand, there's a lot of ground control infrastructure that supports the ISS that doesn't care how m

I wonder what the marginal cost per crewmember is. On the one hand, there's a lot of ground control infrastructure that supports the ISS that doesn't care how many crewmembers there are. On the other, the cost of resupply missions is probably directly proportional to the number of mouths. Maybe it's $35k per night, but meals cost extra (a lot extra).