Factoring humans into space station design

摘要

How many astronauts does it take to move a piece of hardware from one part of the space station to another? The question may sound like the start of a joke, but space station planners at NASA ask it in earnest. After all, it is extraordinarily expensive to train and launch the astronauts into space. Once they arrive, NASA wants to keep them busy. So the agency carefully plans each task, down to the number of minutes it takes various numbers of people to perform.