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Kilometer-High Waves Flow In Saturn's Rings
An anonymous reader sends along a Cosmos Magazine piece on the discovery by NASA's Cassini probe of vertical structures in Saturn's rings, 150 times as high as the rings are thick. The structures were seen because a once-every-15-years orientation of the rings caused vertical features to cast visible shadows. "NASA's Cassini probe has uncovered for the first time towering vertical structures in Saturn's otherwise flat rings that are attributable to the gravitational effects of a small moon. 'We thought that this vertical structure was pretty neat when we first saw it in our simulations,' said John Weiss, the paper's lead author at the Cassini Imaging Central Laboratory for Operations in the US city of Boulder, Colorado. 'But it's a million times cooler to have your theory supported by such gorgeous images. It makes you suspect you might be doing something right,' he added." Update: 06/17 19:29 GMT by KD : The CICLOPS team sent a note correcting the attribution of the quote; the linked article also had it wrong, and has since been corrected.
Are the conservative estimates an example of the Scotty factor. In other words if the team is 90% confident that the mission will last 5 months do they then quote 3 to management - that way if they mission carks it after 4 then they are still covered? I would imagine even the scientists and engineers are very concerned about managerial aspect like project tracking and meeting specification now.
More to the point, how do they estimate such a difficult and unpredictable mission parameter anyhow? I mean somethings like battery life, wear and tear and so on must be quite well understood, but others like the stress of launch, damage, and the great "other" option must be much harder to predict.
It's not so much the Scotty factor as standard engineering procedure for years. If you're told to design an elevator to life 5 people, you make sure it can hold 10 just to be safe. If the design requirements from NASA say "Four years", you design for 6 or 8. You don't want to be penalized for early failure, after all.
And I don't know how the engineers estimate life expectancies, but most components aren't mission-enders. You worry mostly about things like fuel/reaction mass and power sources, first. These are relatively predictable. Other parts that fail generally seem to do so gradually. (Electronics degradation, the reaction wheels on Cassini, etc.) So while you wouldn't necessarily have predicted that a priori, you can track it once it starts to happen.