Keeping Warm on Mars

[Northstar1989]

I've been telling people for YEARS, including here on these forums, that Mars really wouldn't be that difficult to keep warm on because the atmosphere is so thin.  On a cold day on Earth, your main source of heat-loss is convection, but on Mars the atmosphere is FAR too thin to suck much heat out of you.  And besides that, you have to wear spacesuits on Mars anyways (due to the very thin atmosphere), which provide a considerable amount of passive insulation...

Anyways, now the American Meteorological Society has finally released some hard facts on this I'd like to present everybody with.  The following article (the link is to the summary, you can download the PDF of the article for free on the page) contains a mathematical analysis and scientific discussion of windchill on Mars, as well as a helpful table of Earth Equivalwnt Temperatures (EET's) for a variety of temperatures and windspeeds on Mars.

http://journals.ametsoc.org/doi/full/10.1175/BAMS-D-12-00158.1

 

To give an idea of what the data looks like, a temperature of -40 C on Mars with a 20 kilometer/hour wind is the equivalent of a -10 Celsius (14 degrees Farenheit) day on Earth with still air and no direct sunshine (so slightly warmer-feeling than a -10 C night, as the upper atmosphere is warmer during the day and you get slightly more infrared radiation from the sky than at night...)

Of course, -10 C would be easy to keep warm in walking around in a spacesuit on Earth, perhaps doing physical labor.  Maybe even *too* warm (spacesuits are heavy and bulky, and you exert yourself a lot just moving in them...)

 

Regards,

Northstar

Edited February 13, 2017 by Northstar1989

[Scotius]

Well. Considering that current spacesuits have no trouble keeping astronauts warm and alive in hard vacuum, during the night to boot - i don't think anyone was seriously worried about keeping astronauts from freezing on Mars's surface. I'd be more worried about high levels of radiation, limited mobility etc. Though of course this new data are good news - it means that spacesuits tailored for Mars missions could be lighter and less bulky (and less expensive of course), now that we know their thermal insulation can be thinner.

[Shpaget]

I don't remember us ever having a serious discussion about the issues of heating on Mars.

We did have multiple discussion about the issues of cooling down and getting rid of excess heat regarding satellites and probes (not to mention all the space warfare stuff).

[kunok]

The insulation isn't designed for no direct sunshine, a surface can get very hot with sun radiation even in the lower W/m² of mars.
And insulation works both ways, a good insulation makes it difficult to cool an installation, humans and machines needs constant refrigeration that isn't in mars
We already have gotten this conversation and you didn't listen to any argument. And insulation is an "easy" problem (just not like you oversimplifies) but thermal control systems won't be that easy. But still thermal problems are one of the easier problems in an hypothetic martian base.

@Shpaget we didn't really have, probably it was north saying again and again that a antarctic base is a lot harder than martian base because it needs more insulation, like thermal control were a bigger problem than getting O₂ or food or whatever... I don't recall what was the thread, but at least with me that was the discussion

[GDJ]

Considering that Mars does have an atmosphere (albeit a very thin one) thermal control devices that would work on Earth would work on Mars, but would have to be re-engineered to work in the thinner atmosphere. Getting a enclosure to warm up isn't a huge issue, getting to cool down might but I'm pretty sure that Mars won't need Air Conditioning like we know it. Dark surfaces, circulating air within cavities inside dark/light zones, solar heating, leftover heat from RTG's, and so on and so on. I'm not sure if Geothermal would be an option on Mars, but I'm sure there is still lots of heat down there. Fluid systems (aka boilers and radiators) to distribute heat isn't an issue, and it's rather efficient if it's designed properly.

Probably the biggest hurdle honestly is building an enclosure that stays sealed and has radiation shielding.

My 2¢: Start buying stocks in companies that make Aluminum Oxynitride panels and start building really heavy duty greenhouses.

Edited January 22, 2017 by GDJ

[ColKlonk2]

Not only that, the ground is also poisonous, so going underground is not a solution.

Take it or leave it, we're not going to Mars anytime soon, no matter what Elon Musk and others like you to believe

Edited January 22, 2017 by ColKlonk2

[kerbiloid]

A convection-based air conditioning would work poor on Mars because of 0.001..0.01 atm pressure.
Or they should throw out hot gas or steam much denser than the Martian "atmosphere".
Probably they should either use radiators or heat huge underground water reservoirs.

Anyway, once they heat the Martian ground, they will smell perchlorates being decayed and vapourized.

[GDJ]

2 minutes ago, kerbiloid said:

Anyway, once they heat the Martian ground, they will smell perchlorates being decayed and vapourized.

Add some ammonia to those and we have rocket fuel!! (ammonium Perclorate).

Win.

;)

Edited January 22, 2017 by GDJ

[DerekL1963]

o.0  Yeah, I'm wondering where the OP spent years explaining all this as well...  Because in twenty years on the 'net I've never seen anyone who thought it wasn't possible to stay warm on the Martian surface.

The actual problem is the exact opposite - not turning the suit into a sauna.  The atmosphere is too thick for sublimation cooling (as was used on the Moon), and too thin for for pretty much every other kind of cooling.

[PakledHostage]

3 hours ago, DerekL1963 said:

o.0  Yeah, I'm wondering where the OP spent years explaining all this as well... 

I do recall it being mentioned in response to a post I made where I pointed out that mining communities in the high arctic (Pyramiden and Nanisivik, to name one or two examples) tend to become ghost towns once the economic motivation to live there is removed, but the response was merely a straw man argument... 

I never said that those places become ghost towns simply because it is cold. What I said is that they become ghost towns because the existence is bleak and most people will only put up with it if there is an economic incentive to do so. The cold is only one aspect of what makes them bleak; there are plenty of others too.

[Shpaget]

44 minutes ago, PakledHostage said:

high arctic

But that's not Mars.

[PakledHostage]

19 hours ago, Shpaget said:

But that's not Mars.

No, but it is the best analog for Mars that we have here on Earth. Mars is even more hostile yet NASA still uses Ellesmere Island for Martian simulations.

Edit: I was wrong about NASA's using Ellesmere Island. The project that I was thinking of is on Devon Island: https://www.nasa.gov/exploration/humanresearch/analogs/research_info_analog-haughton.html

Edited January 23, 2017 by PakledHostage

[NSEP]

But how about the ground? How cold is that?

[magnemoe]

On 22.1.2017 at 7:01 PM, DerekL1963 said:

o.0  Yeah, I'm wondering where the OP spent years explaining all this as well...  Because in twenty years on the 'net I've never seen anyone who thought it wasn't possible to stay warm on the Martian surface.

The actual problem is the exact opposite - not turning the suit into a sauna.  The atmosphere is too thick for sublimation cooling (as was used on the Moon), and too thin for for pretty much every other kind of cooling.

Ice should sublimate on Mars too, 

Now on Titan keeping warm might be an problem its very cold and the thick atmosphere should remove heat fast.

Saw an TV program about diving and then diving very deep as in +200 meter keeping warm is an major problem. 
Divers at this depths operate out of an diving bell with an umbilical hose who provide air and hot water for heating.
If umbilical get stuck or stop working diver can disconnect it, the main issue was not air as they have an emergency bottle but cold. I guess insulation don't work so well under that pressure and that air with 20 bar pressure transfer heat faster.  

[kerbiloid]

As Titan surface is composed of mostly water ice with frozen hydrocarbons and ammonia, would be funny to build a building and warm the ice underneath.

Probably the human Titanians should keep their colony of high piles. And even then it should stay in a boiling lake.

Edited January 23, 2017 by kerbiloid

[DerekL1963]

52 minutes ago, magnemoe said:

Ice should sublimate on Mars too

I didn't say ice wouldn't sublimate, I said the atmosphere was too thick for sublimation cooling.  Two totally different statements.

[magnemoe]

35 minutes ago, kerbiloid said:

As Titan surface is composed of mostly water ice with frozen hydrocarbons and ammonia, would be funny to build a building and warm the ice underneath.

Probably the human Titanians should keep their colony of high piles. And even then it should stay in a boiling lake.

Some of the same problem you face on ice or even permafrost. 
 

[mikegarrison]

I wouldn't be surprised if any "spacesuits" on Mars would actually be mechanical counter-pressure suits. Those might not be nearly so bulky or inherently warm.

On 1/22/2017 at 8:24 AM, ColKlonk2 said:

Not only that, the ground is also poisonous, so going underground is not a solution.

Going under the ground on Earth can be poisonous too (radon gas, etc.), but it's fairly easily solved by adding an impermeable lining to the walls of your underground space.

[FleshJeb]

That's a fun article. Thanks, Northstar.

Quote

On Earth, where convection dominates, the popular wisdom is to dress in layers so that clothing can be added or removed to maintain comfortable skin temperatures when activity level or ambient temperature changes. Because radiant heat transfer is the dominant heat transfer mechanism on Mars, significant adjustments to heat balance might be conveniently accomplished by varying the emissivity of the outer surface of the pressure suit or of some garment worn over it.

"Mom! I'm going to Mars!"

"Don't forget your sweater!"

[kerbiloid]

6 hours ago, magnemoe said:

Some of the same problem you face on ice or even permafrost. 

Certainly, but at least they don't smell and burst.

[MichaelPoole]

On 22. 1. 2017 at 5:24 PM, ColKlonk2 said:

Not only that, the ground is also poisonous, so going underground is not a solution.

Take it or leave it, we're not going to Mars anytime soon, no matter what Elon Musk and others like you to believe

Why would the ground being poisionous prevent anything? Nobody is going to eat the soil.

[kerbiloid]

Btw, as perchlorates mean chlorine, it's not only poisonous, but also corrosive.

[MichaelPoole]

1 hour ago, kerbiloid said:

Btw, as perchlorates mean chlorine, it's not only poisonous, but also corrosive.

Now, perchlorates are corrosive (through I don't even know if they were even conclusively proven to exist in the Martian soil), but "perchlorates mean chlorine", what? Are you implying that a molecule with chlorine it it = chlorine? Salt also "implies chlorine", besides, I don't think a base structure made of titanium or something will be ruined by something found in fertilizer?

[kerbiloid]

29 minutes ago, MichaelPoole said:

I don't even know if they were even conclusively proven to exist in the Martian soil

https://en.wikipedia.org/wiki/Perchlorate#On_Mars

29 minutes ago, MichaelPoole said:

but "perchlorates mean chlorine", what? Are you implying that a molecule with chlorine it it = chlorine? Salt also "implies chlorine", besides, I don't think a base structure made of titanium or something will be ruined by something found in fertilizer?

Being heated, they released monoatomic oxygen. They can act in exchange reactions producing a spectre of chlorine salts (aren't you going to use only stainless steel on Mars? there will be different materials and substances).

[MichaelPoole]

Is 0.6 percent of perchlorate really such an insourmountable obstacle to you?

https://en.wikipedia.org/wiki/Perchlorate#On_Mars

Quote

The analyses on three samples, two from the surface and one from depth a of 5 cm (2.0 in), revealed a slightly alkaline soil and low levels of salts typically found on Earth. Unexpected though was the presence of ~0.6% by weight perchlorate.

 

Edited January 24, 2017 by MichaelPoole