Meanwhile, the station astronauts continue their own informal experiment in living. If and when the crew size is expanded, more structured psychological studies will be able to explore the dynamics of large, multinational crews. Dan Bursch worries that we haven’t yet found the magic number: “Three is a challenge for a long-duration crew. Five or six would help ease any personality conflicts.” Sergei Krikalev agrees. “That’s why we are flying a test bed. I think the smart thing to do would be to test different crew sizes in orbit now…. Then we can say which is better.”
It’s one of the many unfinished experiments on the station—and for astronauts hoping to one day live on the moon or Mars, perhaps the most important of all.