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A friend of mine is running a Deathwatch campaign and we were trying to figure out what sort of temperatures Space Marine armor could withstand. Cold is not really an issue as the suit would be able to withstand complete vacuum (therefore near absolute zero) for as long as the life support systems lasted. The real question is as to how hot can it get where the armor would still protect the wearer (again at least until life support failed). I have not been able to find any answers so far; while i'm sure there is no definitive answer, perhaps a consensus can be reached that will help.

Terminator armour is supposed to be modified from suits designed to gominto active plasma reactors. Therefore normal power armour probably can't do that. It also depends on how the heat is applied. In space where one side will bevroasted by the sun, but the other is in shadow and near 0, there is opportunity to radiate heat away on the shadow side. In a compartment fire where the whole space is at high gas temperatures its harder to reject heat from an object. Then you're limited to using some kind of thermal dump system where all the heat you don't want in the person you dump into another object (fluid is often referenced for this because its easier to distribute around the armour) and then you can simply dump the fluid if it gets too hot. Peter F Hamilton has written several hard dci-fi books with realistic spacecraft systems where all this is explained rather well.

The scenario we are trying to figure out is similar to the prison planet from Chronicles of Riddick, where there is very little atmosphere and as a result, the day-side of the planet is constantly burning from the intense heat, but the night side is near 0. I would think that it would probably be at least 1k degrees but that is purely a guess on my part.

In that case, if you watch the scenes where they're running on the surface, the rock looks warped and twisted; the horizon also showed a blast wave approaching. That means the sun was close enough to instantaneously heat the rock surface with explosive force. It was also enough to vaporize a body in less than a minute. I would guess that a suit of power could last a few minutes, perhaps ten.

To be honest, if they can survive in the freezing vaccum of space, they'd have internal heating and cooling systems similar to the human body, in fact it might not even be the suit, it might just be something to do with their anatomy..

Space is relatively easy. Its only 273 below zero and its simple to electrically heat things, especially if you have your own micro fusion generator. Having something survive at hundreds of degrees centigrade is much harder. The energy has to go somewhere. Unless they have some kind of perfectly insulating layer, the heat will eventually get through. 100mm thickness of concrete gives you about 1 hour if exposed to 1000degC. Also if there is a perfectly insulating layer in there somewhere, how does the suit dump body heat? You just end up boiling yourself alive.


Automatically Appended Next Post:
Also, if the radiation is intense enough to flash-melt rock then you would be talking surface temperatures of 3000+degC.

 Mr Nobody wrote:
In that case, if you watch the scenes where they're running on the surface, the rock looks warped and twisted; the horizon also showed a blast wave approaching. That means the sun was close enough to instantaneously heat the rock surface with explosive force. It was also enough to vaporize a body in less than a minute. I would guess that a suit of power could last a few minutes, perhaps ten.

Ok, this helps a lot actually. I think I will go with this for the sake of simplicity and lack of any hard numbers on the matter. Thanks for all your answers

On the flipside, a guardsman with a flame thrower can potentially cook a group of space marines in their armor with one blast...

Prom-juice burns real hot, yo.

Given the Riddick planet comparison, I'd provide the Space Marines caught in the "hot side" a matter of rounds before they died equal to their armor's current AP, plus 1/2 Toughness Bonus.

Also, the armor loses 1 AP per round of exposure to the heat as it cooks/melts away.

 Flinty wrote:
Space is relatively easy. Its only 273 below zero and its simple to electrically heat things, especially if you have your own micro fusion generator.

Space is cold, but there's also nothing to conduct heat away from you. Our astronauts actually risk getting too hot in their suits, not freezing. Astronauts have heat-reflective outer covers on the suit in order to not pick up too much heat from solar radiation, and liquid cooling systems in order to get their own body heat transfered away.

A marine in a PA suit will have even worse problems getting rid of excess heat as his suit has more systems producing heat. .

Spetulhu wrote:

 Flinty wrote:
Space is relatively easy. Its only 273 below zero and its simple to electrically heat things, especially if you have your own micro fusion generator.

Space is cold, but there's also nothing to conduct heat away from you. Our astronauts actually risk getting too hot in their suits, not freezing. Astronauts have heat-reflective outer covers on the suit in order to not pick up too much heat from solar radiation, and liquid cooling systems in order to get their own body heat transfered away.

A marine in a PA suit will have even worse problems getting rid of excess heat as his suit has more systems producing heat. .

It depends on how good a radiator PA is fitted with. It does have a magical backpack, after all

Spetulhu wrote:
Space is cold, but there's also nothing to conduct heat away from you. Our astronauts actually risk getting too hot in their suits, not freezing. Astronauts have heat-reflective outer covers on the suit in order to not pick up too much heat from solar radiation, and liquid cooling systems in order to get their own body heat transfered away.

A marine in a PA suit will have even worse problems getting rid of excess heat as his suit has more systems producing heat. .

Outer space is almost totally empty; liquids boil before they can freeze because there's no pressure. It's not "cold" per se. Fortunately, your precious bodily fluids are still under pressure so they won't boil away. Unfortunately, your precious bodily fluids are subject to ebullism when you're exposed to vacuum; the nitrogen gas in solution inside your tissues will start to bubble and cause catastrophic damage to your squishy innards.

Everything else (heat is more of a concern than cold) is accurate.

Isn't there some kind of energy shielding provided, not just pure armor alone?

Normal power armour doesn't have any energy shielding. It is "power" armour becasue it has power assisted joints and artificial muscle fibres to enhance the strength of the wearer. The armour itself is variously noted as mixtures of plasteel and ceramite with ablative layers on the shoulder pads.

Also space is the very definition of cold. The ambient temperature is about 3 degrees above absolute zero and anything hanging in outer space will very rapidly dissipate all its thermal energy.

 Flinty wrote:

Also space is the very definition of cold. The ambient temperature is about 3 degrees above absolute zero and anything hanging in outer space will very rapidly dissipate all its thermal energy.

Actually it will dissipate very slowly through radiation because space is a vacuum (or near enough). That is why things like vacuum flasks are good at keeping your hot drink hot. There is no convection or conduction to get rid of heat. Somebody risks overheating before anything else if they have anything producing heat on them. If you left something out in space long enough and it didn't pick up heat from other sources (like solar radiation) then eventually it cool down to a fraction above absolute zero, but that takes time and is certainly not the instant freezing portrayed in movies. But astronauts in their suits worry about heat more than cold.

This is an example of the trope:

http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsCold

Its a fair point. However a thermos flask is also efficient because it has a relatively small surface area, compared to its cross section/volume. I guess I have in my head the view that direct thermal radiation is more effiicient that perhaps it is. I know that in earth's orbit, direct solar radiation is a big problem. Out in the depths of space there is no such energy source, though, so you would be left with only the heat energy being generated by the suit itself.

 Flinty wrote:
Out in the depths of space there is no such energy source, though, so you would be left with only the heat energy being generated by the suit itself.

Their own metabolism produces heat, which is trapped in their suits. They have liquid cooling these days just because of that - if they didn't they'd suffer heat stroke if they did EVA work. A NASA astronaut came close to death of it in 1966, and a Russian cosmonaut had a cooling system malfunction in 2004 which could have been just as dangerous.

Spetulhu wrote:

 Flinty wrote:
Out in the depths of space there is no such energy source, though, so you would be left with only the heat energy being generated by the suit itself.

Their own metabolism produces heat, which is trapped in their suits. They have liquid cooling these days just because of that - if they didn't they'd suffer heat stroke if they did EVA work. A NASA astronaut came close to death of it in 1966, and a Russian cosmonaut had a cooling system malfunction in 2004 which could have been just as dangerous.

This. The human body produces much more waste heat than anyone would be aware of in day-to-day life, because our convection/evaporation cooling system (aka sweat) is quite efficient. But once you start containing that heat (ever wrapped up in a high-efficiency thermal blanket?) it gets uncomfortable very fast. Only a few degrees rise in core temperature can risk permanent brain damage (as with fevers), as well as temporary symptoms such as heat stroke. Space Marines can control their metabolism, but if they're engaged in anything active they're going to be generating large quantities of waste heat and the suit is going to need to dump it somehow.

From what I understand:

PA and Terminator suits are a fully enclosed environment. As long as they are not damaged, and have power, they can sustain a Marine indefinitely. It stands to reason that the suits have the ability to heat and cool themselves, although I don't think the process has ever been discussed. From a gaming perspective, the internal workings of power suits are only important to really hardcore Gear Geeks. From a "fluff" perspective, the Adeptus Mechanicus would probably tell you that such things are the province of only the most venerated Tech-Priests.

From reading, I could easily believe that the Techs don't understand how these suits work, they just follow the instructions to join circuit board A with control module B, while burning the Incense of Soldering", when they want to build a new one. Repairs are conducted in a similar fashion: by rote, rather than by understanding.

Armor implies a dense, refractory material, which ought to be resistant to heat transfer. The suits' ability to maintain life-sustaining temperatures in space implies their ability to do the same in other environments. By approximating the opposite of the conditions in space, you could come up with some fast and dirty numbers for what sort of range of extremes the suits could withstand.

My guess would be that the muscular, communications, and optics processing hardware would fry before the Space Marine.

Likely a few thousand degrees.

Lasguns are ineffective vs. Power armor, it seems, and they probably run that hot in their concentrated beams. Plasma (of the sort they use in 40k), is likely 20,00-30,000 degrees (like the plasma used to cut metal).

I think I read somewhere 500 degrees C is easily tolerable.

Also depends on their geneseed. A salamander is much better at tolerating heat that a space wolf, but likewise, a space wolf could survive in the cold without power armour at tempratures a salamander could not.