Mix seven shuttle astronauts and six space station residents and you set a record for the biggest off-the-planet gathering.

NASA is aiming to launch Endeavour on Saturday morning to the international space station for a long, laborious construction job. When the shuttle pulls up, there will be 13 people at the station — the most people ever together in space at one time.

Everyone — astronauts and managers alike — agrees it will be a challenge managing so many people. Just last week, space station resident Bob Thirsk said coordinating this first new crew of six was “a little bit like herding cats.”