In Moscow this week, six Europeans voluntarily locked themselves into the same small living quarters. They'll be there for 105 days. It's not some kind of group honeymoon — it's an experiment to see how human beings can live, work and maintain their health and sanity locked in the same small space — as if they were in a space capsule bound for Mars.
Close quarters can breed complaints. A Russian cosmonaut complained that he's not allowed to use the U.S. toilet and exercise bike aboard the International Space Station — because of billing problems.
Astronaut Mark Kelly is familiar with the challenges of space flight. He's been in orbit three times, most recently on NASA's 123rd space shuttle flight, aboard Discovery. Host Scott Simon talks to Kelly about this week's space news.