Perhaps the most important insight NASA has gleaned from studying team dynamics—in space and on Earth—is the preciousness of one trait in particular: a sense of humour. Studies of crews overwintering at the South Pole show that a confined group needs people to fulfil various roles, including leader, storyteller and social secretary. But the most important task by far is that of the clown, a person who is funny and also wise enough to understand each member of the group and defuse tensions.

How to prevent conflict on the way to Mars