Space Station Success.

Call it a marriage made in the heavens. On December 6, astronauts aboard the space shuttle Endeavour "tied the knot" between Zarya and Unity, the first two modules of the International Space Station (ISS). The historic hook-up marks the foundation for the largest space venture ever to build the first permanent space research lab (see SW 9/7/98).

To accomplish this pioneer mission, the shuttle crew first had to chase down the Russian-made Zarya, which has been orbiting Earth since November. Some 384 kilometers (240 miles) above Earth, astronaut Nancy Currie used a robotic arm to snare Zarya. For two hours, she carefully drew Zarya close to the shuttle's cargo bay, where the American-made Unity sat waiting.

"We've never done anything like this before," Currie said. Once Currie positioned the two modules within inches of each other, shuttle commander Robert Cabana fired thruster rockets to raise the shuttle and clamp the two parts together.

Then, during three, six-hour space walks, astronauts connected power cables between the modules, and turned on the lights, computers, and air conditioning.

Zarya will act as the space station's "tugboat"--providing propulsion, power, communications, and a docking port for temporary living quarters. Unity, a six-sided space capsule, will serve as a docking port for future ISS components.

At least 45 more shuttle missions and rocket launches will be needed to haul about 100 major components of the ISS into orbit. The next mission, scheduled in the spring, will deliver the Service Module, which will temporarily house the ISS crew until the space station is complete. When finished in 2004, the ISS will serve as a "beehive" of scientific activity.