It's sunrise in space.

Actually, it's Zarya -- that's Russian for sunrise -- and it's the first piece of the long-awaited, much-debated International Space Station. For all its notoriety, as the first step in this historic space mission, the Zarya is a sturdy workhorse, similar in design to the 11-year-old space station Mir.

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Here are its essentials: Zarya weighs 42,600 pounds and is 41.2 feet long and 13.5 feet wide. Initially, it will provide propulsion, navigation, altitude control, electrical power and communications for it and the next module, Unity. (That piece will be carried into orbit from the space shuttle Endeavour, which will lift off December 3 from the Kennedy Space Center.) As more space station components reach orbit, Zarya’s functions will gradually scale back, and it will be used mainly for storage and external fuel tanks.

As you might suspect, getting this first piece ready for space has involved some complex international arrangements. NASA's prime contractor, the Boeing Defense & Space Group, paid the Khrunichev State Research and Production Space Center in Russia $200 million to build the module. But 47 of Zarya's units used for command, control and data operations were built by the Honeywell Satellite Systems Operations in Arizona.

The module was actually finished two years ago after its solar arrays were tested in the temperature extremes of space – plus 50 degrees Celsius to minus 50 degrees Celsius. It then underwent successful docking tests with a pressurized mating adapter, the Russian-manufactured hardware that links all the pieces of the station. After some final tests of its computers and the addition of orbital debris shielding, early this year it was shipped to the launch site in Kazakhstan about 1,300 miles southwest of Moscow.

Zarya rode into orbit on a Proton rocket from the Baikonur Cosmodrome, where Sputnik's 1957 launch began the human exploration of space. After separating from the rocket's third stage, Zarya will zip along in a 137- by 211-mile elliptical orbit. The module's systems, solar arrays and communications antennas will deploy automatically.

After preliminary tests, Russian mission control will fire Zarya's engines to move it into a circular orbit 240 miles from Earth. There it will stay, a yellow-school-bus sized fruit fly soaring along at 17,000 mph on stubby solar wings, awaiting the arrival of U.S. astronauts and piece number two, the Unity module.