PROTECTING the International Space Station from being punctured by shards of
space debris could add as much as $5 billion to the project鈥檚 spiralling
costs.
Nobody can agree on the station鈥檚 true price tag. Earlier this year, an
independent team of investigators said that NASA鈥檚 estimate of $17.4
billion was more than $7 billion too low. The General Accounting Office
(GAO), the research arm of the US Congress, has estimated the total development
cost to be about $21.9 billion.
But Allen Li, an associate director with the GAO, told the House of
Representatives Committee on Science last week that both of these estimates
overlook the problem of space debris. 鈥淣ASA recently updated its overall
requirement for space debris tracking to include the ability to track and
catalogue objects as small as 1 centimetre,鈥� Li told the committee. But that
will mean a major upgrade, as the system, now run by the Department of Defense鈥檚
Space Surveillance Network, has trouble tracking particles less than 10
centimetres across.
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The station鈥檚 hull could be punctured by these particles. 鈥淚t鈥檚 capable of
withstanding pieces of debris up to 1 and perhaps 2 centimetres,鈥� Goldin told
the committee. 鈥淭racking down to 1 centimetre is a very tough job. It鈥檚
something that we must work on.鈥�
How this work will be funded is still unclear. Upgrading the system will
require antennas with higher resolution and improved signal-processing
facilities. Goldin told the committee that any extra costs incurred by the space
station would come out of NASA鈥檚 existing budget. But if the cost is as high as
$5 billion, as Li鈥檚 report to Congress suggests, that would be
impossible. 鈥淭here鈥檚 no more water in that well,鈥� says James Sensenbrenner, who
chairs the House science committee.