What EXACTLY happens to us on Venus?

[Souper]

if a human dies on Venus..... i have 3 questions.

1. Precisely how long would he survive? (measured in milliseconds)

2. What would happen to the chemicals in his body?

3. Would his body get picked up by Venusian winds and hurls upwardly into the atmosphere?

[Godot]

Considering the fact that Venus has > 500 °C and 92 atm at "sea level", I guess the death would be almost instandly.

Also I would guess that the organic components of the body would denature very quickly, due to the high heat as well as the influence of the sulphuric acid rain

I don´t think that the remnants that remain (which could be picked up by venusian wind) could be called "body" anymore

Everything on the prerequisite that the human doesn´t wear any protective suit (which probably would resemble that of a deep sea diver)

(there was actually a nice series named "Defying Gravity" which was canceled all too soon ... and featured a good depiction of a venus walk .. see pics and vidlink below)

Edited August 24, 2014 by Godot
Added Vid

[RuBisCO]

If a human magically appeared on the surface of venus they would be dead mad quick, like splat splat! Chemically what would happen is a process called pyrolysis: a person would carbonize, Biomass -> C + CH4 + CO2 + H2O + N2 + other elemental solids. The surface winds speeds are pretty low but I would figure the carbonized body would puff into coal dust and blow away.

Edited August 24, 2014 by RuBisCO

[Jesrad]

At 92 bar pressure the venusian atmosphere is quite conductive of heat, so a human exposed would be rapidly cooked as if deep-fried. Body fluids would boil while body fat would liquefy (then boil too) and the rest would break apart. Basically, it'd look a bit like deep frying a chicken nugget in molten lead with a splash of sulfuric acid on top: you'd quickly get a foaming, spitting mass of coalescing black stuff sticking to slowly dissolvig bones.

Yuck

[Brotoro]

It does not rain sulfuric acid on Venus. It's clouds are made of droplets of sulfuric acid, yes, but any that rains down toward the surface evaporates long before it gets anywhere near the surface.

[Godot]

It does not rain sulfuric acid on Venus. It's clouds are made of droplets of sulfuric acid, yes, but any that rains down toward the surface evaporates long before it gets anywhere near the surface.

Oh, interesting ... thanks for correcting this

[Jesrad]

The vaporized sulfate would probably recombine topically into sulfuric acid in contact with the body's water (though not for long).

There is also a very nice depiction of an EVA at ground level of Venus in BBC's Space Odyssey: voyage to the planets. (My only gripe with this show is the aurora in vacuum from the magnetic shield...)

[RuBisCO]

I have a problem with the idea of EVA on venus. First of all the surface gravity means a spacesuit that weights 100 kg on earth is going to feel like a spacesuit the weighs 90 kg, it going to be really heavy! On the moon or mars with the weight cut down to 1/6 or 1/3 even there space suit weight is a concern, on Venus it would be less of a concern and just plan devastating. Imagine walking around in 4 suits of armor on top of each other here on earth! Atmospheric diving suit here on earth that can handle half those pressures, they weigh nearly 500 kg! I don't know can someone calculate out the density of the atmosphere on venus's surface, maybe the suit can be made buoyant.

Second how do you make a pressure suit that can handle 450°C AND 92 atm of pressure. That temperature is going to buckle the joints! Technologically even robots that can operate on Venus are beyond bleeding edge technology, its still theoretical that we could even build electronics that can operate at 450°C... a space suit that can do it is simply unreal!

[xenomorph555]

I have a problem with the idea of EVA on venus. First of all the surface gravity means a spacesuit that weights 100 kg on earth is going to feel like a spacesuit the weighs 90 kg, it going to be really heavy! On the moon or mars with the weight cut down to 1/6 or 1/3 even there space suit weight is a concern, on Venus it would be less of a concern and just plan devastating. Imagine walking around in 4 suits of armor on top of each other here on earth! Atmospheric diving suit here on earth that can handle half those pressures, they weigh nearly 500 kg! I don't know can someone calculate out the density of the atmosphere on venus's surface, maybe the suit can be made buoyant.

Second how do you make a pressure suit that can handle 450°C AND 92 atm of pressure. That temperature is going to buckle the joints! Technologically even robots that can operate on Venus are beyond bleeding edge technology, its still theoretical that we could even build electronics that can operate at 450°C... a space suit that can do it is simply unreal!

The weight isn't the hard part, with a robotic exoskeleton like a raytheon XOS2 the person will hold. The other reasons such as the ones you pointed out are why it's nearly impossible. I believe whats needed is a tank not a suit.

Also we can send robots to venus and we have, they did not operate at that temperature though, it may be possible but probably not.

Edited August 24, 2014 by xenomorph555

[Godot]

Well, in both movies/series depicting EVAs on Venus (i.e "Defying Gravity" as well as "Space Odyssey") the time is extremly limited.

In Space Odyssey it is 1 hour.

In Defying Gravity it is even just 20 mins (which actually was exceeded by the female astronaut, leading to the seals becoming porous, the suit nearly failing before her return and her getting large scale burns on her body)

Same goes for the lander in Defying Gravity, which also was meant to only spend 30 mins on the surface of Venus

[Hattivat]

As pointed out above, EVAs as traditionally understood would require ridiculously sturdy suits, going up to the point where it is debatable whether it still counts as EVA when your "suit" looks more like a tank or a mecha. At this point you can just as well attach robotic legs and arms to your lander and treat it as one huge "suit".

However, I've seen someone else propose a solution that would let an astronaut take a few steps on Venus with his own muscles, even though it would hardly qualify as an EVA: Have a structure resembling a diving bell at the bottom of your craft. After landing, lower it it to the surface and create a tight seal. Pump out the venutian atmosphere from the bell, pump in survivable atmosphere, open the hatch and voila, you can safely take a few steps in boots with good thermal insulation. This way, perhaps it would even be possible to .... at Venus.

[edit:] As for the landings in Defying Gravity and Voyage to the Stars, the troubling aspect for me is that their landers are capable of launching from the surface back into orbit. Not only that, they are also both SSTOs. The estimates of the amount of delta-v needed to launch from Venus vary widely, but with extreme Isp losses expected due to air pressure, as well as massive drag, and the atmosphere generally extending higher than the Earth's, you can expect the actual figure to be in the ballpark of 20 000 m/s of delta-v. I don't think any of the seriously proposed technologies (other than project orion) could achieve 20 km/s in a single stage while maintaining a TWR of >1.

Edited August 24, 2014 by Hattivat

[RuBisCO]

Well cooling is fine and all but keeping it cool with arm and leg joints is simply not possible. The exposed outer-joints have to operate at 450°C, then there would need to be dewar vacuum insulator and an inner joint cooled. I don't think we have the technology for such an outerjoint: it will expand upon heating, it will buckle. Certainly 20-1 hour times are real-ish in that they take into account the insanity of trying to function at those temperatures. All the probes landed on venus were pre-cooled and operated until "melting down" for about 1 hour. Either we would need some kind of amazing heat pump that can pump out heat over a 430°C differential or we would need electronics that can operate at very high temperatures, and that is just for a sustained robotics presence of more then 1 hour!

[lajoswinkler]

If an astronaut's suit would jettison in pieces, exposing him suddenly to the environment of 92 atm, loss of consciousness would occur in few seconds due to the blunt trauma of the soft tissues containing gas and pressure effects on the gases dissolved in water. Atmosphere would ram the tissues into the lungs and the abdomen cavity would partially collapse. Eardrums would collapse. Severe internal bleeding would occur. The rest would structurally resist because there's no free gas. Hair curls up, melts and chars in the first moments, too. Eyes would coagulate quite fast and ooze out. Consciousness would not be lost immediatelly and suddenly. There'd be considerable suffering.

The temperature of the atmosphere is very high, but it's supercritical fluid of a molecular compound and not a solid touching the body. Heat transfer is slower, so it wouldn't be like dipping into molten zinc. The fact is that our body is around 60% free water and 4.181 kJ/kg°C for water is a lot. Sudden exposure to 92 atm is a lot more serious thing. However, surface charring is a possibility in few minutes.

After loss of consciousness, heart would go into fibrillation during the next few seconds because of loss of blood and increasing heat effects. Soon after, the heart stops working completely as the proteins start to coagulate above 45°C.

Brain death probably in the first minute. Random neuron firings would slowly stop in the next few minutes as the temperature of the brain increases.

Now comes the "cool" part.

Interstitial fluid and plasma begin to boil a bit above 100°C at 1 atm. On Venus, it would boil at some 300°C. This probably means that tissues would lose their elasticity (100°C and 1 atm, the body swells like a sausage in a microwave and then bursts, releasing steam) as it is thoroughly cooked. Heat crawls inside towards the body core. Water can't boil, but it can cook the tissue.

A bit above 200°C, fat starts to degrade, creating smoke.

After 300°C is reached, boiling begins. Probably in the next 30 minutes or so. It could be calculated, but the values would be quite rough.

Tissue flops and oozes from the skeleton, releasing steam and smoke. It would be a gruesome sight. Volatiles inside the skull would seep through eye sockets, ear canal and probably the great foramen of the brain. Long bones such as femur could crack suddenly, releasing volatiles.

As water is slowly going away, smoking becomes more apparent. Tissues lose their compound water, too. Acrylamide is released. Maillard reactions give way to charring. First few centimetres of the body would be charred in an hour, maybe less.

I'd say the complete carbonization throughout the body would take at least one whole day.

So... yeah. You don't want that.

Edited August 24, 2014 by lajoswinkler

[Jovus]

We have built robots that function in the Venusian atmosphere for quite a while (measured in hours). For examples, see http://en.wikipedia.org/wiki/Pioneer_Venus_project and http://en.wikipedia.org/wiki/Venera_7

[RuBisCO]

We have built robots that function in the Venusian atmosphere for quite a while (measured in hours). For examples, see http://en.wikipedia.org/wiki/Pioneer_Venus_project and http://en.wikipedia.org/wiki/Venera_7

Again that is a precooled probe, the best time on the surface was Venera 13 at 127 minutes before it failed, that just over 2 hours. A inhabited ship is going to need to operate for a lot longer than that! I calculate out that a probe jammed with glycerol and with a very good dewar insulator could last for maybe a day or two. 400 kg of glycerol against 500 W of input heat could keep a probe cool at 17.8 °C (melting temperature) for 45 hours. Glycerol has nearly no density change upon melting so one could fill all the probes void space with the stuff. The other alternative is paraffin wax which has comparable performance but is not as dense so less of it can be jammed in. That would be the best pre-cooling and heat storing could do, after that one will need heat pumps and the power system for those pumps, to keep something at room temp against venuses over 450°C is insane.

Let this JPL slide show on the idea of a long term venus lander-probe illustrate all the problems in achieving even that: http://www.lpi.usra.edu/vexag/meetings/archive/vexag_7th/oct2009/presentations/hunterVenusLanderTechnologies.pdf

[Rainbowtrout]

-snip-

Thank you for that totally non-graphic explanation. Just what I needed before dinner

On topic, you wouldn't last too long. You're being attacked by the "jar of antimatter" of planets.

[MrShadowGames]

Indeed a lovely description of a Venus "Body check"