So the atmosphere at the surface of Venus is about 90 times that of Earth, right? We send probes to the bottom of the ocean, which is much denser than that, and yet we don't send probes to Venus' surface. Why not?

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We, humanity, have. But it is tough to make a probe survive in the conditions of the surface of venus, which includes temperatures hot enough to melt lead, something not found in earth's ocean depths. The survival time of probes on venus is measured in minutes as opposed to months for probes on mars. So it comes down to a question of is the scientific payoff from a short lived probe, that will have to have a large part of its mass dedicated to simply protecting itself rather than scientific instruments, worth the cost compared to alternative missions that could be done.

Basically what Ronald Brak said. We've mapped the surface of Venus quite well, and there's not really a need for other space-based missions to Venus. The MESSENGER mission to Mercury is to finish mapping the planet and to see what we can find there. Any landers for Venus would be hard to pull off well and hard to justify money-wise. Mars landers can survive on its surface and provide plenty of interesting data, whether or not we find water or life.

Venus' surface is just too harsh, and there are better planets to go into orbit around.

Two main reasons:
1.) The problem on Venus isn't the pressure, it's the heat; it's very difficult insulate a probe against it, let alone to radiate away any excess.

2.) Venus has taken a backseat to Mars for many reasons: some historical, others purely scientific. The planetological community currently favors the search for past or present water (and life) on Mars to Venusian studies, though I myself think the planet is underrated.

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There were the Venera landings. But, the atmosphere is dense and hot, and that's tricky to deal with. Here's a short description of a Venus rover idea that uses a heat pump to keep the electronics cool enough to operate:

http://www.grc.nasa.gov/WWW/RT/2003/...10landis3.html

An RTG would be the likely way to power it, and that's an issue too (Pu-238 is in short supply). Anyway, it's not at all easy, but there will likely be something like this one of these days.

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Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

A Venus surface mission is a high priority. The surface conditions are tough, but I know there are contracts out for electronics that are able to work in the ambient temperature, as well as research on power generation on the surface so that active cooling could be used for electronics that could not be designed to work at the hot temperatures.

http://pdf.aiaa.org/preview/CDReadyM...V2004_5622.pdf

Nice seeing you back about BAUT, space.

NASA Lunar and Planetary Science: Venus

Current and Past Missions

Venus Express - ESA Venus Orbiter (2005)
MESSENGER - NASA Mercury Orbiter (2004) (Two Venus Flybys)
Magellan - NASA Venus Radar Mapping Mission (1989-1994)
Pioneer Venus - NASA Orbiter/Probes to Venus (1978-1992)
Galileo - NASA Mission to Jupiter (Venus flyby - 1990)
Vega 1 - Soviet mission to Venus and Comet Halley (Venus flyby - 1985)
Vega 2 - Soviet mission to Venus and Comet Halley (Venus flyby - 1985)
Venera - Soviet Venus Missions (1961-1983)
Mariner 10 - NASA Mission to Venus and Mercury (1973-1975)
Mariner 5 - NASA Venus flyby (1967)
Mariner 2 - NASA Venus flyby (1962)

Future Missions

BepiColombo - ESA Mercury Orbiters and Lander (2013) (Possible Venus Flyby)
Planet-C - ISAS Venus Orbiter (2010)

Also there: image catalogs, maps, references.

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A major reason implicit in the reasons given above but not explicitly
stated: In exploring Mars we are scouting out a place that we expect
humans to go to in the very near future, while humans on Venus is
pretty much an impossible dream at present.

-- Jeff, in Minneapolis

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http://www.FreeMars.org/jeff/

"The other planets?
Well, they just happen to be there, but the point of rockets is to explore them!"
-- Kai Yeves

Why not some probes that are designed to float like balloons below the cloud cover. They could photograph the surface, and monitor the wind velocity

If space exploration budgets were unlimited, I'm sure there'd be more Venus missions.

'till then, choices have to be made.

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Well. . . at the right altitude, Venus is in fact the nicest place to live besides Earth. Nice pressure, nice temperature, a surprising amount of natural resources can be taken directly from the atmosphere, and telerobotics would be much easier with next to no light speed delay. Power is abundant, the reflectivity of the clouds mean you could put solar panels on the bottom as well as the top, and you could use direct energy conversion by letting long 'tentacles' down into hell, and make power from the temperature gradient. As for cosmic rays and such, no magnetic field I am afraid, but then, neither does Mars, and all the atmosphere above you would provide considerable protection. So, all in all, I wouldn't quite call Venus 'impossible'.

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Some probes have been sent to Venus and essentially worked like that. The air is so soupy that even a probe that's designed to descend all the way to the ground doesn't need a parachute; it just slowly sinks. But sometimes even those don't survive long enough to reach the ground, and the ones that did have all worked less than an hour and a half after landing, before being crushed, melted, and dissolved by the air (which is not just high-pressure and high-temperature but also acid). So we have gotten some data back from them, but just not a lot, so there's not much of a "rate of return on investment".

Attached Thumbnails

 

Thank you for the lovely thumbnail of where Hades goes to die.

I'd love to see more concentration on Venus. Venus is interesting now, our probes to Mars seem to be geared towards finding out if it was interesting in the past.

Geologically, Venus is a mystery. Some seismometers would be nice. Can you make one that can hover at 50,000 ft? Ultra-sensitive radar perhaps?

Darn it's hot there! What is it? 700 degrees Fahrenheit? My kitchen oven doesn't even get that hot full bore. Add ninety times Earth's air pressure and you have one toasty afternoon under the cloudy skies. Oh yeah, there's sulfuric acid in the air as well, perhaps even raining down, as if it really matters.

It's a very interesting place and the parallels with Earth make it a very interesting and perhaps important study. It is, after all, our sister planet.

It's nowhere near cool enough for sulfuric acid to be a liquid.

There do seem to be substances there which have a "cycle" like water does here: vaporizing, condensing into clouds, precipitating as a liquid or as tiny snow-like solid crystals, landing in liquid pools, then vaporizing again. Some of the mountain tops shine with its "snow" pack like ours do, where it's cool enough that the solid precipitation form can stay solid after it lands.

But the stuff that acts that way isn't water, or sulfuric acid... it's one or more particular kind(s) of metal.

Woah, then collecting that metal snow, would be a great way to collect ultra pure ores. Conviniant for a smallish scale habitat that doesn't have its smelting equipnment up and running. Think about it, a large sheet made of say, abstestos or some such, held at four corners by balloons with rock ballast. Then, when they have accumulated a load, they meet in they meet in the middile, drawing the bag togther, then the release the ballast, and float up to the recovery zone.

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Is not Venus a better place to find life? (even at it surface?)

I wonder..what is the temperature on the poles? i dont think shouldnt be a lot lower than the normal +400ºC...but how knows , maybe theres is a surprise for me

Unfortunatly, you will be suprised. Venus isn't so hot because it is so near the sun, it is so hot because of the ultimate greenhouse effect. All the CO2 and other stuff in the atmosphere trap and lock the heat in tight. So Venus is pretty much the same tempeture night and day, pole to equator.

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Actually the surprise was to know if there are lower temperatures , i know there arent mant possibilities

also i fixed a typo :P

@zerocold I think there is a very little chance of finding life on Venus. But the history of Venus is very interresting I think. Maby in a far past there was life on Venus.

Also I would like to know what causes the extreme greenhouse effect on venus

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