Backdropped by Earth's horizon and the blackness of space, the International Space Station is seen from Space Shuttle Atlantis as the two spacecraft begin their relative separation.
WASHINGTON -- NASA's attempt to finish the International Space Station by the time it retires its space shuttle fleet in two years would require much to happen and very little to go wrong, a congressional auditor told lawmakers Thursday.
"It will be a challenge for NASA to complete the space station by 2010 given the compressed nature of the schedule, maintenance and safety concerns, as well as events beyond its control, such as weather," said Cristina Chaplain of the Government Accountability Office, the investigative arm of Congress.
Chaplain testified before the House Science and Technology Subcommittee on Space and Aeronautics.
Its chairman, Rep. Mark Udall, a Colorado Democrat, said he was impressed with the space station's progress but expressed concern over how NASA plans to sustain the project after the shuttle's retirement.
"If we are to receive a meaningful return on the nation's investment in the ISS, we need to ensure that the station's post-shuttle logistics resupply needs are adequately funded," he said.
Chaplain said that for NASA to finish the space station within the next two years, the agency must stick to its current aggressive schedule -- just slightly less demanding than the one it pursued prior to the Columbia disaster. At the time of the 2003 accident, NASA launched a shuttle about every other month and used four vehicles -- one more than its current fleet -- to maintain its schedule.
Ten more flights are scheduled before NASA retires the shuttle in 2010. That schedule includes two contingency" missions that would deliver critical spare parts to the station.
Chaplain pointed out that once the space station is finished, NASA will have a hard time supplying it because there won't be spacecraft large enough to carry necessary cargo.
The agency will be relying heavily on the Russians, and eventually on the Europeans and Japanese, to supply vehicles that can service the space station once the shuttles retire. But, she noted, none of those vehicles are capable of bringing cargo back.
Chaplain also noted that NASA must complete the space station to expand its scientific research. Currently, most of the crew's time is spent maintaining the station, as opposed to conducting experiments.
According to NASA, the crew spends no more than three hours per week on science, she said.
Rep. Dana Rohrabacher, a California Republican, noted the testimony of several scientists who spoke about the medical research taking place because of the space station. Rohrabacher said he viewed himself as a great supporter of the space station, but he doubts whether any of the scientific accomplishments mentioned have been validated.
"I've heard a lot of rhetoric today. I've been listening to that rhetoric for 20 years," he said. "I'm satisfied with the fact that we now have capabilities of building structures in space. I would hope they're not just pyramids. . . . I hope there is something that comes out of it in terms of a cure for a disease. Believe me, I've been listening to that for 10 years, I haven't seen it yet."
- VIDEO: Orbital Arrival: Europe's Jules Verne ATV Arrives at ISS
- VIDEO: Europe's Special Delivery to Space Station, ATV Mission Control
- VIDEO: Part 1: Europe's First ISS Cargo Ship, Part 2
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