Water-cooled lander |
Water-cooled lander |
Aug 22 2007, 05:22 PM
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#1
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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 26 2007, 02:39 PM
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#2
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Member Group: Members Posts: 903 Joined: 30-January 05 Member No.: 162 |
{Going out on a limb here}
Could we put a satellite on the (IIRC) L1 position between Venus and the sun, and put some retroreflectors on the surface of Venus. The satellite would continuously illuminate whatever retroreflector was visible with an appropriate microwave frequency and monitor the reflected signal for frequewncy shifts ?? Retroreflectors near the limb of Venus would be sensitive to vibrations parallel to the surface, and the retroreflector directly below would be sensitive to up and down motions. We would be looking for rapid (but tiny!) frequency variations caused by seismic vibrations in the return signal, and we could ignore the slow shifts caused by the (slow) Venusian rotation. {I remain innocent of the frequency stability requirements for the satellite, but the retroreflectors seem to be feasible from a materials science standpoint} |
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