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Space base heads back to the drawing board.

Space base heads back to the drawing board

NASA sent its space station designers back to work upgrading their ideas last week after an internal study warned that without major modifications to the $37 billion project, astronauts would have to devote well over 3,200 hours a year in spacewalking activities just to maintain the earth-orbiting base.

NASA released the study July 20, along with a second report that offered 100 recommendations that its engineers estimate would cut the need for time-consuming and potentially dangerous extra vehicular activities (EVA) to 485 hours a year. These include modifying some parts to last longer and need less repair; redesigning certain components so astronauts inside the station can fix them with robots; removing nonessential systems to lessen repair needs, and developing ways to reduce the time required to prepare for a spacewalk.

The space station remains in the design phase, with the fabrication of its parts still several years away. NASA says its astronauts will begin orbiting and assembling the station's components in 1995.

"The maintenance problem starts the day of the first element launch," notes John E. Pike, director of the Space Policy Project at the Federation of American Scientists in Washington, D.C. One NASA official says repairs required during the station's assembly pose a major concern, because astronauts must use the space shuttle for both living and as a work base.

Coming so soon after NASA's troubles with the Hubble Space Telescope and the grounding of the three space shuttles, the need for significant design revision inevitably renewed questions about the need for the space station and NASA's ability to succeed with such a complex and costly project.

Pike, for one, envisions no abrupt end to congressional support for the space base. "But it does mean NASA will have to get its act together," he says. An aide says Sen. Jake Garn (D-Utah), who has orbited Earth aboard the space shuttle, and other members of the Senate appropriations subcommittee that handle NASA's budget, are "not thrilled" with the report. But Garn views NASA's planned corrections as "what the agency should be doing."

The surprising estimate on the space station's maintenance requirements came from a panel headed by astronaut William F. Fisher and robotics specialist Charles R. Price of NASA's Johnson Space Center in Houston.

Considering the time needed to prepare for a spacewalk, the actual time outside the space station, and the uncertainty of how long specific repairs may take, the Fisher-Price panel concluded that maintaining the permanently occupied space base would require 3,276 astronaut hours a year, or an average of nearly nine astronaut hours a day. The six-month, $1 million study's figure nearly doubles that of an earlier NASA study, which estimated a need for 1,732 hours of EVA-related maintenance annually.

One factor affecting the EVA-related hours is the need for astronauts to breathe extra oxygen for several hours before entering space. Currently, NASA uses space suits pressurized to 8 pounds per square inch and plans to operate the space station at 14.7 psi. To avoid the bends, astronauts must spend about five hours pre-breathing oxygen for a one hour EVA. NASA engineers estimate it would cost $300 million to develop space suits pressurized at 14.7 psi. Reducing the station's pressurization to 8 psi would require costly retesting of equipment to make certain it would not fail at that pressure level.

The Fisher-Price report also notes that the space station design includes some 8,000 individual items that will either need scheduled or unplanned maintenance. And, it says, the designs for most of these components remain "too immature" to determine how much time it will take to service them.
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Title Annotation:NASA's space station designers
Publication:Science News
Date:Jul 28, 1990
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