Antique Fridge Could Keep Venus Rover Cool

Hugh Pickens writes "In the 1970s and 80s, several probes landed on Venus and returned data from the surface but they all expired less than 2 hours after landing because of Venus' tremendous heat. It's hard to keep a rover functioning when temperatures of 450 C are hot enough to melt lead but NASA researchers have designed a refrigeration system that might be able to keep a robotic rover going for as long as 50 Earth days using a reverse Stirling engine. NASA has not committed to a Venus rover mission, but a 2003 National Academies of Science study recommended that high priority be given to a robot mission to investigate the Venusian surface helping to answer such questions as why Venus ended up so different from Earth and if the changes have taken place relatively recently."

Comments

i've always said

[circletimessquare]

venus is a better terraforming candidate than mars. oh sure, if you want to get somewhere as quickly as possible that is vaguely hospitable to settlement, mars beats venus hands down

but if you want to talk about recreating earthlike conditions (water, temperature, gravity, atmospheric density), i think it would easier (easier, not easy) to precipitate out venus' atmosphere than to bulk up mars'. and if you stood on venus right now, you would weigh roughly the same. big bonus right there

where is all the water going to come from? how the heck do you thin out the venusian atmosphere to earth-like densities? i don't know. but however you do it, it's an easier starting scenario than mars

Re:i've always said

[Average_Joe_Sixpack]

i don't know. but however you do it, it's an easier starting scenario than mars

Probably not due to the 243 day rotation.

Re:i've always said

[schnikies79]

Isn't the problem with mars a lack of a magnetic field which allows the solar wind to strip away the atmosphere? I don't see how we could jump-start a magnetic field, so whats the point of even trying to rebuild the atmosphere if it's all going to blow away?

How about the lack of gravity? Can you build atmospheric pressure comparable to earth with lower gravity?

I saw Zurbin give a talk at my Univ a couple years ago and was going to ask him about it, but I forgot.

Re:i've always said

[CorSci81]

Well, Earth has managed to safely sequester billions of tons of carbon. We have just as much of it as Venus, ours just happens to be locked up in nifty things like carbonate rocks. Venus could have carbonate rocks too if we could just get it a little cooler and get some water back on the surface to help with erosion. Just at present the reaction goes the wrong way and you have CaCO3 + SiO2 -> CaSiO3 + CO2, so there aren't a lot of carbonate rocks laying about. In terms of atmospheric composition if you removed most of the CO2 from Venus's atmosphere it'd have roughly the same amount of nitrogen, which is a good starting point, and you only need to liberate oxygen from a relatively small amount of the CO2 that's presently there for a breathable atmosphere.

Re:i've always said

[inviolet]

Well, in terraforming terms, finding stuff to make up the Martian atmosphere probably isn't that hard. There are significant CO2 ice caps, and there may be significant water available with modest effort. CO2 plus plants gives you O2. Also, there is some good evidence to suggest that the icecaps' existence is bistable -- that is, if you could mostly evaporate them, the additional greenhouse effect would warm the planet enough to finish the job and keep it that way.

Eh... better to leave Mars alone. It will be the perfect home for any future silicon-based intelligent life, because it lacks the two chemicals (water and oxygen) that play such hell with metal components.

Assuming that humans can overcome their "OMG we'll be obsolete!" paranoia about post-humans, it would be teh awesome if carbon-based intelligence on Earth could coexist peacefully with silicon-based intelligence on Mars. Assuming.

Not bloody likely, of course, but it's an awesome thought. Terraforming Mars would waste that fantastic opportunity, all for the sake of the outdated "meat86" system architecture.

1970's refrigerator?

[downix]

Sterling's are older than the 70's. I've been tinkering on using a sterling for cooling off an engine block for a few years now (pretty good results too, allowing me to generate electricity from the previously wasted heat).

Albert Einstein invented a safer refrigerator

[MichaelCrawford]

Back in his day, refrigerators used gaseous ammonia as the refrigerant, which is highly toxic. He was appalled to hear of a whole family being killed by a leaky refrigerator, so he and Leo Szilard invented one that had no moving parts, and thus without the risk of leaky seals.

Leo Szilard was later instrumental in launching the US' Manhattan Project to build the atomic bomb. It was his idea, but he got Einstein to write the letter to President Roosevelt that convinced him to fund the project.

Venus' landscape is awesome

[amightywind]

Wouldn't the rover just beam back "It's hot and everything's melted" over and over lol. If I remember correctly, there's no significant features to even study. You can't have mountains and ancient, dried up rivers and caves when everything's that hot. Mars is far more interesting.

It's hot and nothing is melted. On earth the melting point of rock is lowered by the amount of water they contain. Water acts as a flux. On Venus where the climate is intensely hot and dry, crustal rocks melt at a very high temperature and are very strong. They create some pretty wild landforms (scarps, cliffs...) as a result.

This or this don't seem so boring to me. The Maxwell Montes are higher than the Himalayas. With adiababic cooling their tops will be hundreds of degrees cooler than the planetary mean. Also, with all of the volcanism and mobile lava flows you can expect there to be some amazing lava rivers and lava tube caves.

The Fraud of Venus' Supposed Thermal Equilibrium

[pln2bz]

Few people on this forum take the time to carefully consider the story of our investigations to date of Venus' exceptionally high temperatures. It is a very interesting story that has incredible ramifications for science to this day. The various probes sent there did not say what NASA wanted to hear, so it was decided that the *assumption* of global energy balance would take priority over the sensor data. And this is how the theory of CO2-based global warming survived one of its first scientific challenges ...

If one assumes that Venus is the sister planet to Earth, formed out of swirling stellar material billions of years ago along with the Earth, then Venus should be about 20 degrees warmer at any given latitude than Earth is. And, in fact, that is what was taught 50 years ago before we had sent any probes to peer beneath Venus' dense cloud cover. When the 900 degree F surface temperatures of Venus were discovered in 1970 by the USSR's Venera 7 probe, Carl Sagan devised his "super greenhouse" theory, which instantly became the standard theory for explaining the extreme surface temperatures on Venus. Sagan's claim was that the less than 2% of solar energy which somehow finds its way through the thick carbon dioxide clouds of Venus to the surface is forever trapped there and cannot re-radiate as infra-red flux, and thus escape (flux is a measurement of an amount of something that flows through a unit area per unit time).

The only competing theory at the time was posited by Immanuel Velikovsky, who pointed to evidence supporting the notion that the planet Venus was a new planet that was still in the process of cooling down. Although Velikovsky's "Worlds in Collision" was so popular with the public that it once held the title of bestseller, the mainstream astrophysical community scoffed at the notion that an outsider whose expertise was in linguistics could offer any value whatsoever to a discussion about Venus' hot temperatures.

Carl Sagan's theory would require that Venus' atmosphere be in something called thermal balance. In other words, in order to rule out the possibility that Venus' heat originates from the planet itself, scientists must establish that the heat absorbed by Venus from the Sun must equal the heat emitted by Venus back into space. If Venus' surface was emitting more infrared light than the sunlight it was receiving, then Sagan's greenhouse theory would be ruled out and scientists would have to consider the possibility that Venus was probably cooling down from some past catastrophic event --a finding that could lend credence to Velikovsky's assertion that Venus was a new planet.

The November 13, 1980, issue of New Scientist contained an article titled, "The mystery of Venus' internal heat". It reads as follows:

Two years surveillance by the Pioneer Venus orbiter seems to show that Venus is radiating away more energy than it receives from the sun. If this surprising result is confirmed, it means that the planet itself is producing far more heat than the earth does.

F.W. Taylor of the Clarendon Laboratory at Oxford presented these measurements at a Royal Society meeting last week. Venus surface temperature is higher than any other in the solar system, at 480 C. The generally accepted theory is that sunlight is absorbed at Venus' surface, and re-radiated as infrared. The latter is absorbed in the atmosphere, which thus acts as a blanket, keeping the planet hot. It is similar to the way a greenhouse keeps warm.

Pioneer has shown that there is enough carbon dioxide and the tiny proportion of water vapor needed to make the greenhouse effect work -- just. If this is the whole story, the total amount of radiation emitted back into space, after its journey up through the atmospheric blanket must be exactly equal to that absorbed from sunlight (otherwise the surface temperature would be continuously changing).

But Taylor found that Venus radiates 15 percent more energy than it receives. To keep the surface temperature constant