CAPE CANAVERAL, Fla. - Up at the space station, the tenants are still getting used to having twice as many people around. Now, they're getting seven house guests who will stay for nearly two weeks.

Talk about inconvenient timing. But NASA has little choice but to hurry things along, if it hopes to finish the international space station by the end of next year.

With that deadline in mind, NASA is aiming to launch space shuttle Endeavour Saturday morning on a space- station construction mission that should complete the huge Japanese lab.

The space-station crew doubled to six late last month, and when the shuttle pulls up with its crew of seven, there will be 13 people aboard the station - the most people ever together in space at once.

Everyone - astronauts and managers alike - agree 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."

Space shouldn't be a problem. With nine rooms, two toilets, two kitchens and two mini-gyms, the nearly completed orbiting complex can accommodate 13, at least temporarily. Plus there's a bathroom, a kitchen and exercise equipment on the visiting shuttle.

NASA's biggest concern is keeping the communication loops clear, especially during the five planned spacewalks.

Imagine 13 people in your house, all doing something different and having questions, said flight director Holly Ridings.

Together, the astronauts will add the final segment to the huge Japanese lab, store big spare parts to the outside of the station, change batteries and perform other maintenance work. All three robotic arms, two on the station, will be required.

The 13 space travelers represent all the major space station partners: seven from the United States, two each from Russia and Canada, and one each from Belgium and Japan.

NASA has instituted no rules for crowd control, but has had plenty of discussions and even rehearsals to ensure that things go smoothly. With so much to accomplish in "rapid fire fashion," Ridings said, there won't be time to spare.

"I'm sure there are going to be growing pains, there's no doubt about it," Polansky said.

There's a pecking order for workouts, for example - Polansky, his co-pilot and the returning space station resident get first dibs on the exercise equipment. The two pilots need to be in prime condition for landing their ship following 16 days of weightlessness.

Some of the shuttle crew also will get restroom assignments to limit the amount of urine collected aboard Endeavour once a new outdoor porch is attached to the Japanese lab for experiments. NASA wants to avoid dumping Endeavour's waste water overboard, once the porch is installed right in the line of fire.

Speaking of waste, the shuttle guests will be welcome to drink the station's recycled water, made from the station crew's sweat and urine. Station residents have been sipping it since last month and regularly use it for cooking. *