Illustration of Zvezda before docking. Photo: NASA

Built by RSC Energia, the Zvezda module measures 43 feet long, weighs 42,000 pounds and stretches 95.5 feet across its two solar arrays. It includes three pressurized compartments and 14 windows.

Zvezda will dock with the Zarya module of the international space station using a docking port on its forward end. That port and two others, one facing up and the other down, are located in the forward pressurized transfer compartment, a small spherical chamber.

A fourth docking port is located in an aft transfer chamber where Progress and Soyuz ferry craft will dock. In between is a large open work compartment where the station's controls and crew quarters are located.

Future Russian laboratory modules will be attached to Zvezda's unused ports.

Similar in design to the core module of the Mir space station, Zvezda - the Russian word for "Star" - will provide living quarters for the station's initial three-man crews, along with the necessary life support systems.

The accommodations include a kitchen with an oven, refrigerator and freezer, a high-tech zero-gravity space toilet, a conference/dining table, exercise equipment and compartmentalized sleep stations with their own windows.

Waste water and condensation will be recycled through an Elektron oxygen generation system similar to the one aboard the Mir station. But waste water will not be recycled for drinking.

The forward end of Zvezda. Photo: NASA

In recent months, questions have been raised in the United States about high noise levels and possibly poor ventilation in the Russian module. Additional insulation was installed aboard Zvezda and the first full-time crew will be equipped with ear plugs and other noise abatement gear if needed.

"I think we've got a good program in place," said astronaut Robert Cabana, director of space station operations for NASA. "I don't think it's going to be a long-term problem for the space station. It's something we have to deal with right now. But for the short-term, for these crews going up, it's really not a concern."

Future crew will install quieter, more efficient fans along with additional external shielding against possible impacts by space debris.

Zvezda is equipped with state-of-the-art German-built computers provided by the European Space Agency that will control the space station's orientation, orbital altitude, electrical distribution and environment, working in concert with computers in the Zarya and Unity modules.

Zvezda can be refueled by Progress tankers and its main engines will be used periodically to boost the station to higher altitudes, offsetting the natural orbital decay caused by the station's passage through the tenuous extreme upper atmosphere.

"Service module is the central module of the Russian segment of the international space station," said Malenchenko. "It's going to be used for providing commands and communications for all other Russian parts of ISS."