Water-cooled lander |
Water-cooled lander |
Aug 22 2007, 05:22 PM
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Member Group: Members Posts: 214 Joined: 30-December 05 Member No.: 628 |
There is a recent posting on Emily's Planetary Society blog, which must be Doug's because she's not there herself, although her name is the only name on it. The subject is using water to cool a long-lived surface probe on Venus. It sounds far more practical than any of the other proposals for landing giant atomic-powered refrigerators, or developing a whole new family of high-temperature semiconductors, etc.
But I didn't understand the whispered criticism to the effect that the Ekonomov paper assumed that the water would absorb heat only from the one watt of power driving the instrument package itself. I simply can't believe that he went to the podium and presented his model without taking into account the fact that the surface of Venus is a pretty hot place, and that the proposed probe would be absorbing the ambient heat. This is an interesting proposal and I would like to understand both the original calculation of 50 days to bring the water to a boil, and the cited flaw in the calculation. I too find it hard to believe that it would take 50 days to bring water to a boil on the Venusian surface, but where exactly is the error, and what remains after we correct it? Doug is busy of course, but I hope he will find the time to address this when he returns, if someone else hasn't done so by then. |
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Aug 24 2007, 03:04 AM
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Director of Galilean Photography Group: Members Posts: 896 Joined: 15-July 04 From: Austin, TX Member No.: 93 |
Aw dang, all my best ideas get stolen! First the ultrasonic backup detector for car bumpers, now this! What's next, a front door answering machine?!
Anyways, I was thinking that the frequency could be modified by changing the size and contents of the balloon water. More water takes longer to heat&cool down, plus with the right mixture you can extend the freezing/boiling points to make the range larger. The balloon could catch and contain the water flowing down the inside of the balloon within a container to let it sink even further. Hell, combine this with Ekonomov's idea of using water as the phase-change material, and you get a balloon that can lift-off when its instruments get too hot, and come back down once the water jacket has refrozen. Keep a little filler gas (neon) in the balloon to keep it from completely collapsing on the way down, and you get yourself a free parachute too. -------------------- Space Enthusiast Richard Hendricks
-- "The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke Mother Nature is the final inspector of all quality. |
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