My Assistant
Water-cooled lander |
Aug 22 2007, 05:22 PM
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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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tanjent Water-cooled lander Aug 22 2007, 05:22 PM
helvick QUOTE ..The concept is based around a 60-centimete... Aug 22 2007, 06:32 PM
tty Why start at 300 K rather than 270 K? By shielding... Aug 22 2007, 08:41 PM
djellison Unfortunately - the guy's english wasn't v... Aug 22 2007, 09:03 PM
RJG These calculations are based on the use of water. ... Aug 22 2007, 09:59 PM
tasp None of my steam traction engine information sheet... Aug 22 2007, 11:08 PM
Greg Hullender Tasp: the idea was that the water is INSIDE a glor... Aug 23 2007, 06:16 AM
marsbug QUOTE (Greg Hullender @ Aug 23 2007, 07:1... Aug 23 2007, 01:36 PM
djellison QUOTE (marsbug @ Aug 23 2007, 01:36 PM) A... Aug 23 2007, 01:52 PM
djellison The principle would be to have the pressure vessel... Aug 23 2007, 12:03 PM
AndyG Marsbug - you're maths is somewhat awry.
Thin... Aug 23 2007, 02:22 PM
marsbug Thanks Doug and AndyG! This makes it seem a bi... Aug 23 2007, 02:45 PM
AndyG [Excessive quote removed, hopefully before Doug ca... Aug 23 2007, 03:23 PM
helvick All the above makes sense but my understanding is ... Aug 23 2007, 04:13 PM
algorimancer I wonder whether a silica aerogel might be a bette... Aug 23 2007, 05:36 PM
rlorenz QUOTE (algorimancer @ Aug 23 2007, 01:36 ... Aug 24 2007, 07:39 AM
AndyG QUOTE (rlorenz @ Aug 24 2007, 08:39 AM) J... Aug 24 2007, 08:45 AM
tty If we assume that 500 W is a realistic heat input ... Aug 23 2007, 06:25 PM
hendric One idea I've always had for a Venusian balloo... Aug 23 2007, 07:42 PM
djellison QUOTE (hendric @ Aug 23 2007, 07:42 PM) O... Aug 23 2007, 08:52 PM
hendric Aw dang, all my best ideas get stolen! First ... Aug 24 2007, 03:04 AM
tasp Thanx for clarifying what I was trying to convey.
... Aug 24 2007, 03:10 AM
Greg Hullender Taking tty's figures and using 100W instead of... Aug 24 2007, 09:51 PM
djellison That 50 days is to get up to boiling point - and t... Aug 25 2007, 02:16 PM
tty Unfortunately to use the heat of evaporation requi... Aug 25 2007, 05:51 PM
algorimancer Of course, after the MER experience, anything less... Aug 26 2007, 12:21 AM
nprev True enough, actually; there's only so much da... Aug 26 2007, 03:05 AM
JRehling QUOTE (nprev @ Aug 25 2007, 08:05 PM) Tru... Aug 26 2007, 04:39 AM
tasp {Going out on a limb here}
Could we put a satelli... Aug 26 2007, 02:39 PM
JRehling QUOTE (tasp @ Aug 26 2007, 07:39 AM) {Goi... Aug 26 2007, 03:47 PM
ugordan I'm no expert on radio waves by any means, but... Aug 26 2007, 02:52 PM
Greg Hullender Summary:
According to a 2002 NASA publication, i... Aug 26 2007, 06:20 PM
Greg Hullender ugordan: As I calculate it, the Sun-Venus L1 point... Aug 26 2007, 07:12 PM
tty Completely mechanical seismometers were used for a... Aug 26 2007, 07:20 PM
Gsnorgathon Since the topic's already wandered somewhat fr... Aug 26 2007, 09:21 PM
tasp I think we would want a retroreflector (and to use... Aug 27 2007, 02:25 AM
Greg Hullender For some reason, NASA issued a press release yeste... Sep 13 2007, 12:42 AM
JRehling QUOTE (Greg Hullender @ Sep 12 2007, 05:4... Sep 14 2007, 06:20 PM
nnyspace Could a liquid/solid that has a lower density chan... Nov 7 2007, 05:58 PM
djellison The problem is that the latent heat of evaporation... Nov 7 2007, 07:05 PM
nnyspace QUOTE (djellison @ Nov 7 2007, 07:05 PM) ... Nov 7 2007, 10:01 PM
dvandorn Apollo's Lunar Rover used bee's wax to coo... Nov 7 2007, 07:12 PM
AndyG So we have wood used in Apollo hatches (is that ri... Nov 7 2007, 08:31 PM
JRehling QUOTE (AndyG @ Nov 7 2007, 12:31 PM) So w... Nov 8 2007, 05:21 AM
tedstryk Also, natural materials had been used for a long t... Nov 8 2007, 11:32 AM
ugordan QUOTE (JRehling @ Nov 8 2007, 06:21 AM) N... Nov 8 2007, 11:45 AM
nnyspace Speaking of biomaterials, fats, fatty acids and gl... Nov 8 2007, 06:15 PM![]() ![]() |
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