How long do astronauts go away for?

The shortest answer, the one that applies to the vast majority of current crewed flights, is a crew rotation of about six months. But for an astronaut's family, the departure begins long before launch, and the return does not end at landing.

Between selection and the first flight, several years usually pass, filled with basic training and then mission-specific training. This is spread across American, Russian, European and Japanese centres, depending on the station segments and spacecraft used. In the final months, the astronaut moves from one stay abroad to the next; in the final weeks, they are isolated with their crewmates to avoid carrying an infection aboard.

A standard expedition aboard the International Space Station lasts about six months, with relief provided by the next spacecraft. Technical incidents have already extended some stays by several months. The absolute record for continuous flight is still held by Russian physician Valeri Polyakov, who stayed 437 days aboard Mir. At the other end of the scale, private missions docked to the station last only days.

The return opens a rehabilitation programme lasting several weeks: retraining of balance, back and muscles, repeated medical examinations, post-flight scientific protocols designed to measure recovery. Added to this are technical debriefings and public representation duties. An astronaut's commitment therefore extends well beyond the length of the flight itself.