HERE's a sobering thought for the new millennium: over the next 15 years, the International Space Station's controllers can expect at least one "loss of crew member".
Futron, a management consultancy near Washington DC, has released the first results of its attempts to quantify for NASA the risks the station's crews will face. Its "loss of crew member" category includes serious illness leading to the evacuation of an astronaut, as well as deaths.
Futron's preliminary calculations, which the company admits are crude, considered the risks for a station crewed by three astronauts, half way through construction, and extended this to cover a 15-year period. In reality, of course, the size of the space station, and the number of crew, will change.
Experts have been badgering NASA to finish a full risk assessment for the space station. And while they are pleased that the agency is getting round to it, some question the details of Futron's analysis. The consultancy suggests that accidents inside the station are a greater risk to the astronauts than space walks. This a surprise, given the unprecedented amount of space-walking needed to put the space station together.
Futron also calculates that the chances of losing the entire station in any 8-month period lie between 1 in 200 and 1 in 500-meaning there's a 5 to 10 per cent chance of disaster over 15 years. But its calculations suggest that, if this happens, there is a 93 per cent probability that a micrometeorite impact will be the cause. Futron assumes just a 2 per cent chance that fires, explosions or collisions between spacecraft would be to blame.
"I'm struck by how different it is from the experience on Mir," says A. Thomas Young, formerly president of the aerospace giant Lockheed Martin. "They've had no basic problem with micrometeorites, but they've had problems with fires and crashes."
Author: Charles Seife, Washington DC
New Scientist double Christmas issue: 25 December 1999/ 1 January 2000
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