Astronauts forced to make room aboard crowded space station

Another Canadian will blast off on Saturday to join crew on orbiting research facility

Astronauts are preparing for their most ambitious experiment yet on the International Space Station: how to get along and be productive in an isolated, risky and increasingly crowded environment.

With the arrival of the U.S. space shuttle Endeavour, which is scheduled for launch at 7:17 a.m. Saturday from the Kennedy Space Center in Florida, the number of astronauts aboard the station will swell to a record 13, including Canadian Space Agency astronaut Julie Payette.

"I don't know what it's going to be like," said Endeavour commander Mark Polansky, a veteran of two prior space flights. "We know it's going to be challenging with 13 people aboard."

There's a lot more room aboard the space station since Polansky's last visit more than two years ago. Four more modules have been added to the research outpost, which orbits about 360 kilometres above Earth.

The Endeavour crew will deliver and install a porch for science experiments that need to be exposed to the open space environment.

They are scheduled to reach the station less than three weeks after its live-aboard crew doubled in size to six.

B.C. native Robert Thirsk, Europe's Frank De Winne, and Russian cosmonaut Roman Romanenko arrived at the space station on May 29 aboard a Russian Soyuz capsule.

The trio joined Koichi Wakata of Japan, Michael Barratt of the U.S., and Russian commander Gennady Padalka, marking the first time that astronauts and cosmonauts from all the station partners were together in orbit at one time.

The space station currently has nearly 8,000 cubic metres of pressurized space, about the same as a four-bedroom home. It has three laboratories and five other modules with sleeping berths for four, two bathrooms and two kitchens.

The U.S. and Japanese modules have temporary sleeping accommodations for two additional crew members.

The visiting shuttle astronauts said they will try to be good guests, but they will need to use the station's bathrooms and galleys. Shuttle crews typically dump urine and other waste water overboard during flight, but during Endeavour's mission the practice will be curtailed to ensure the station's new porch stays pristine.

That means shuttle astronauts will be encouraged to bypass their ship's toilet in favour of using the station's two bathrooms.

One of the commodes is hooked up to a water recycling system that purifies urine for drinking, which the shuttle astronauts will use.