If all goes as planned, by the end of 2003 the U.S. portions of the space station should be nearly finished, leaving NASA with a new problem: winning approval and funding to step up science operations aboard the orbital outpost.
"We have an ambitious year ahead of us," said shuttle program integration manager Linda Ham at NASA's Johnson Space Center in Houston.
After flying a long-delayed space research mission -- a holdover from 2002 and the final dedicated shuttle-based science flight on the fleet's manifest -- NASA turns its attention to five carefully choreographed missions to finish installing the station's exterior truss.
The trusses hold the station's power-generating solar arrays, as well as radiator panels to keep the station and its equipment properly cooled. The span of interconnected girders, currently stretching 134 feet in length, will expand to 310 feet by the end of the year with addition of four more segments. The final truss component, scheduled for launch in January 2004, will complete the framework at 354 feet.
"The station literally becomes a new spacecraft with each assembly mission," said program manager Bill Gerstenmaier.
Not only will the station look different after each construction mission, the outpost's power production will increase by almost threefold by the end of the year, Gerstenmaier added. The extra power is needed to operate science equipment, life support gear and, eventually, additional laboratory modules.
NASA's shuttles are scheduled to haul a total of 80,000 pounds of equipment and supplies to the station in 2003, including two new sets of solar array wings and three more equipment racks for science experiments in the Destiny laboratory.
Hooking up the new gear will require astronauts to conduct a record 24 spacewalks in 2003. Most will take place with a space shuttle docked to the outpost, but resident station crews will be responsible for about six spacewalks on their own.
"The year ahead will be the most complex so far in the history of the International Space Station," said Gerstenmaier.
After the final truss segment is installed in January 2004, NASA plans to fly a second connecting node, clearing the way for installation of modules built by the European and Japanese space agencies.
Back on Earth, NASA and its partners will be working to make good on a pact to increase the station's crew size. Scientists say a larger crew is crucial to turning the complex into a productive, world-class laboratory.
Barter negotiations are under way with the Russians for additional Soyuz spacecraft, which are used as emergency escape ships for the crew. A Soyuz can hold three people and that is what currently limits how many people live on the station. NASA has announced plans to build a new capsule to accommodate larger crews, but it is not expected to be available as a station lifeboat until 2010 at the earliest.
Still unaddressed is where any additional crewmembers would live. Faced with budget overruns, NASA canceled plans for a four-person habitation module. The agency also has yet to restore funding for science programs cut after the overruns were discovered last year.
NASA pledges its plans won't be willy-nilly. Rather, the agency is working to fold any space station enhancements into a larger blueprint for science and exploration, said Gary Martin, the agency's new Space Architect.
"The space station is absolutely essential for anything else we do in space," Martin said from NASA headquarters in Washington, D.C. "If we look at the long term, humans are moving out in a sustained way and we need to learn more about human health in space.
"From an engineering aspect, the space station is a demonstration of the most complex spacecraft ever envisioned," Martin added. "We're learning how to build it and operate it safely and that should give us the confidence to move beyond."
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(Editors: UPI Photo #WAX2003102001 is available)
