A reality check on dreams for space: the repairs
Saturday's arduous spacewalk to repair a solar panel at the space station is a reminder of the challenges inherent in maintaining new structures 'out there.'
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Typically, astronauts spend weeks, even months, training for an assembly spacewalk that makes no use of robotic arms, says Mr. Hassmann. For Saturday's spacewalk, a small army of engineers and astronauts in the US, Canada, and Russia worked around the clock to devise the repair strategy and to make or modify the tools needed to pull off the repair.Skip to next paragraph
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"People always said that we're going to encounter problems we can't even think of right now and have to be ready for them in some way," says Tom Jones, a former shuttle astronaut who conducted spacewalks to help attach the US lab module Destiny to the space station in 2001. "Well, here it is, that actual unexpected. And it always throws everybody a curve. We'd better get used to this."
The farther from Earth astronauts travel, the more acute maintenance challenges become, notes Larry Bell of the Sasakawa International Center for Space Architecture at the University of Houston.
Planners try to build redundancy into critical systems and to provide the tools and materials for making some repairs. Indeed, one tool Parazynski used to handle the undulating solar array took shape from a sheet of Teflon and some insulating tape in the space station's workshop. But mission planners always face a trade-off between trying to plan for maintenance needs and keeping materials within the weight limits during launch.
Especially when talking about trips to the moon or Mars, "it's a long way back to the hardware store," Dr. Bell says.
For the people involved in such repairs, coping requires several things, specialists say. Managers must make quick decisions about which problems are most crucial to fix, for instance. Crew members must be sufficiently trained and practiced in generic mechanical and spacewalking skills to allow them quickly to adapt what they've learned to unforeseen problems.
As for hardware, Russia's experience with the Mir space station may hold some lessons, Dr. Jones suggests. Its space-station segments essentially were plug-and-play; no spacewalks were needed to make the newly attached modules habitable. But that meant snaking power and cooling lines inside the hull, something ISS designers tried to avoid for safety reasons as well as for more flexibility in configuring the station's various elements. Still, it will be important to reduce the number of adjustments or amount of handwork newly arriving crew members must perform, Jones says.
What comes through loud and clear is that just as the 30-year-old space shuttle remains an experimental craft, the space station as well as habitats on the moon and Mars are, and will be, experimental in their own ways.
"In space, there's no such thing as run-of-the-mill," Dr. Bruckner observes.