"You know, one of these days the service module will launch, and that will break the dam," said NASA shuttle program director, Ron Dittemore. "We have lots of hardware for the space station sitting over in our processing facility, and when that service module launches, there is nothing stopping us."

So far, the infant station is a relatively small two-roomer made up of a Russian space tug and a U.S. docking module that eventually will serve as a passageway to various parts of the outpost.

Next up: The Russian service module. Dubbed Zvezda, or "Star," the 21-ton spacecraft will be launched in mid-July from the Baikonur Cosmodrome in Kazakhstan.

An upgraded copy of the Mir space stations core lab, Zvezda will serve as a command and control center for early station crews. It also will double as living quarters and house the critical propulsion systems needed to keep the station aloft during construction.

After that, NASA will attempt to launch nine station construction missions in a mere 12 months, equaling the greatest shuttle flight rate the agency has ever achieved. Look for that same rapid tempo to continue during the next 15 years of station construction and operations.

"The pace is going to be very hectic," said NASA flight director, Phil Engelauf. "It is a sign of things to come, and its going to be a challenge for the team. But I think everybody is really looking forward to that. Thats what we all came to NASA for."

Heres a look at whats going up, and when, during the upcoming station construction blitz:

• August 19: Shuttle Atlantis will fly on a mission to outfit the inside of the Zvezda module for the stations first resident crew. A spacewalk also will be performed to electrically connect the service module with the rest of the station.
• September 21: NASAs so-called Z 1 truss the metal framework upon which power-producing U.S. solar arrays initially will be mounted will be carried aloft by a crew aboard shuttle Discovery. A communications and television antenna also will launch on the flight, along with a docking port that will provide a parking place for shuttles traveling to and from the outpost.
• October 30: In training since 1996, the stations first resident crew finally will fly up to the outpost aboard a Russian Soyuz rocket and then open the station for business.
• Led by U.S. astronaut William Shepherd, the crew also includes Russian cosmonauts Sergei Krikalev and Yuri Gidzenko. The trio will test-fly the station and pitch in on critical construction jobs during a three-and-a-half-month stay at the station.
• November 30: The stations first power-producing solar arrays will be ferried up to the outpost construction site by a joint U.S.-Canadian crew aboard shuttle Endeavour. Eventually, eight of the arrays each of which will unfold like an accordion and measure 112 feet (34 meters) in length will generate enough electricity to power 55 houses on Earth.
• January 18, 2001: A can-shaped U.S. laboratory that will serve as the central hub of science research at the station will be launched aboard shuttle Atlantis. The 28-foot (8.5-meter) aluminum module will house floor-to-ceiling experiment racks for research in biotechnology, fluid physics, combustion and life sciences.
• February 15, 2001: Chock-full of equipment and supplies for the U.S. lab, the first of three Italian-made space station "moving vans" will rocket up to the outpost aboard shuttle Discovery.

• April 19, 2001: Raising a 480-ton station will require one of the most sophisticated construction cranes ever built, and the first parts of Canadas Space Station Remote Manipulator System will be carried up to the outpost aboard shuttle Endeavour.

• May 17, 2001: An airlock from which station crews can stage spacewalks to build and maintain the outpost will be launched aboard shuttle Atlantis. Both American and Russian spacesuits will be stored in the airlock, which is similar to the type of decompression chambers used by scuba divers.
• June 21, 2001: The third and final Italian "moving van" named Donatello after Italian sculptor Donato di Niccolo di Betto Bardi, will truck up to the station aboard shuttle Discovery. Tucked into the 21-foot (6.4-meter) module which can carry up to 9.1 metric tons of cargo will be a host of U.S. stowage and experiment racks.
• The second resident crew Usachev, Helms and Voss will return to Earth aboard Discovery. Their replacements: U.S. astronaut Frank Culbertson and Russian cosmonauts Vladimir Dezhurov and Mikhail Turin.
• August 23, 2001: A pallet that will serve as a spare-parts warehouse will be rocketed up to the outpost aboard shuttle Endeavour. Mounted on the outside of the station airlock, the warehouse will provide easy access to replacement parts for spacewalking astronauts and cosmonauts performing routine maintenance chores at the outpost.

The yearlong flurry of shuttle flights will be followed by yet an additional 25 assembly missions to be launched on U.S. orbiters before the station is completed in September 2005. Another eight construction flights will be carried out on Russian rockets after the Zvezda service module launch.

And while NASA and its partners face a steep uphill climb to complete the station, project managers say the finished product will be well worth the wait.

"It surely is going to be amazing," said former NASA astronaut Robert Cabana, who now serves as NASAs space station manager for international operations.

"When we're done, we will have a world-class, microgravity laboratory up there doing science 24 hours a day, 365 days a year for the next 10 to 15 years."