The third international space station crew has moved in, after arriving at the outpost Sunday aboard the U.S. space shuttle Discovery. Tons of new supplies are going in with them.

The incoming U.S. commander, Frank Culbertson, and his Russian crewmates, Vladimir Dezhurov and Mikhail Tyurin, have begun their planned four-month stay in orbit.

They have become the official station crew with the transfer of the custom-fitted liners for their seats on the Soyuz emergency escape vehicle.

Now that the personnel exchange is complete, the new trio is receiving the first of several handover briefings from the outgoing team of Russian commander Yuri Usachev and U.S. astronauts Jim Voss and Susan Helms. Station flight director Mark Ferring says these include information on safety procedures, the intricate computer network, and the various station systems.

"They actually have a handover book that we've briefed [them on] on the ground," he said. "They'll take this book, and go through each system. They'll walk them through how you do water samples, how you do maintenance, how you change filters. About a third of their time is going to be spent doing that kind of thing."

As the relief team traded places with the old crew, Discovery astronaut Pat Forrester operated the shuttle's robot arm to transfer a big Italian cargo container from Discovery. It holds more than 3000 kilograms of new supplies for the station.

Mr. Ferring says cargo transfers from this container will begin Tuesday, with the new supplies going into the outpost, and used equipment and trash coming out. The hardware includes the last few scientific equipment racks for the station's U.S. laboratory, which was attached earlier this year.

"Tomorrow is primarily a big workday," he said. "The moving van is here, and all hands are going to be on deck, moving stuff back and forth. And we'll be moving express racks four and five, which are the final express racks, into the lab. We will completely outfit the lab at this point. There are no more open slots, once we've done that."

The new crew will have more time for scientific research than their predecessors did because of a lull in station construction during their sojourn.

The outgoing crew is to return to Earth aboard Discovery next week, and will begin an exercise regimen to strengthen muscles and bones, weakened after five months of weightlessness.