Given the high availability of ISS Commercial Cargo launches for NASA, it would seem that the aerospace stereotype of "mass reduction is paramount" may be outdated. What is the current limiting factor for (pressurized) cargo throughput per launch?
These are the categories I thought of:
- Weight-Constrained: The limiting factor for adding more cargo to a launch is the max payload weight of the launch vehicle.
- Volume-Constrained: The limiting factor is max total volume and/or packing efficiency.
- Crew Time-Constrained: The limiting factor is the time commitment for crew to unpack visiting vehicles, or the max "shelf life" of the visiting vehicle before undocking for reentry.
- Underfilled: NASA doesn't fill cargo volume or mass. This would likely be due to one of a few reasons. 1: Time-sensitive payloads require a faster launch tempo. 2: Risk of launch failure is mitigated by spreading out necessary supplies across semi-redundant consecutive launches. 3: (Unlikely?) NASA lets cargo space go to waste because it already paid but doesn't need the capacity.
To phrase it in a different way, if I wanted to get a package to the ISS, what should I optimize my package for?