# How did the astronauts cope with the drastic temperatures on the moon? **URL:** \ **Category:** Factual Questions\ **Created:** [May 14, 2009, 6:42pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438 "2009-05-14T18:42:55Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![constantine](https://avatars.discourse-cdn.com/v4/letter/c/3bc359/32.png) [@constantine](https://boards.straightdope.com/u/constantine)\ **Post date:** [May 14, 2009, 9:24pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/21 "2009-05-14T21:24:43Z")
> [@UncleRojelio](#): > > [But they do, nonetheless](http://en.wikipedia.org/wiki/Space_suit#Spacesuit_requirements). The lunar spacesuits [circulate chilled liquid](http://en.wikipedia.org/wiki/Liquid_Cooling_and_Ventilation_Garment). A recent episode of the discovery channel show “How do they do it” discussed manufacture of spacesuits, and they discussed the use of chilled liquid for cooling. They said this use of chilled liquid was a relatively recent invention, and that the apollo astronauts said that wearing one of the apollo suits on the moon was about like being in a sauna. ---
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [May 14, 2009, 9:39pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/22 "2009-05-14T21:39:05Z")
> [@xtisme](#): > > Out of curiosity, why do you think this? I remember seeing a show on one of the cable channels where skeptics of the moon landings were discussing this, but for the life of me I couldn’t figure out what their problem was on this issue (nor the vacuum issue either…though it was hilarious to watch the one old guy try and move his hand in the evacuated chamber as if this proved something). > > Could you give some details as to why you find it hard to believe that a space suit could have these performance characteristics? > > -XT When I first found out about the temperature on the moon I imagined me inside a space suit in a large tub of boiling water. I couldn’t imagine that thin suit keeping the heat out. Now I get it! ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [May 14, 2009, 9:43pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/23 "2009-05-14T21:43:47Z")
Gotcha. As I said, was just curious. -XT ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [May 14, 2009, 9:47pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/24 "2009-05-14T21:47:43Z")
> [@YamatoTwinkie](#): > > Temperatures are meaningless. What matters is _heat transfer_ (the same reason why you can last a long time outside in your underwear with an air temperature of ~34F, but jump in a lake at ~34F and you’re dead within a couple minutes). Assuming a lake of what, methane? ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [May 14, 2009, 9:55pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/25 "2009-05-14T21:55:34Z")
Another way you can cool a spacesuit is by allowing a compressed gas to expand. Expanding gas has a cooling effect. People in spacesuits generally have another very good reason for wanting to crack open some gas cannisters, so it all works out pretty well. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [May 14, 2009, 10:09pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/26 "2009-05-14T22:09:04Z")
Space suits currently deal with materials getting +250 deg F. This is for spacewalks, where the sun-side and shade-side changes every 45 minutes (90 min orbits). **constantine** said: > [@](#): > > A recent episode of the discovery channel show “How do they do it” discussed manufacture of spacesuits, and they discussed the use of chilled liquid for cooling. They said this use of chilled liquid was a relatively recent invention, and that the apollo astronauts said that wearing one of the apollo suits on the moon was about like being in a sauna. That seems wrong. The LCGs were in use during Apollo. > **[Insight Data Management](https://lsda.jsc.nasa.gov/books/apollo/S6CH6.htm)** > [@](#): > > The portable life support system supplied oxygen to the pressure garment assembly and cooling water to the liquid cooling garment. The PLSS subsystems were an oxygen ventilating circuit, a primary oxygen subsystem, a liquid transport loop, a feedwater loop, and an electrical power subsystem. > > [snip] > > Liquid Transport Loop > The liquid transport loop (figure 23) was the primary means of crewman temperature control. Water from the liquid cooling garment entered the loop through the multiple water connector. The water was then pumped through the sublimator where heat was given up. The cooled water was used for fan motor cooling before return to the LCG through the multiple water connector. Now maybe one didn’t have the system properly adjusted, or the sublimator wasn’t working right, or something. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [May 14, 2009, 10:34pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/27 "2009-05-14T22:34:29Z")
> [@CurtC](#): > > Further, if you’re walking around on a plain of something that’s 200C, the radiated heat from the Moon’s surface seems like it would be the biggest problem, not the heat transferred through your boot soles. What radiated heat? Again… heat doesn’t radiate through a vacuum. The only way the heat of the surface gets to you is if you touch it, e.g. through your boots. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [May 14, 2009, 10:35pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/28 "2009-05-14T22:35:53Z")
> [@Fear\_Itself](#): > > Assuming a lake of what, methane? You do know that the ~ symbol means “approximately” not “negative,” right? 🙂 ---
**Author:** ![YamatoTwinkie](https://avatars.discourse-cdn.com/v4/letter/y/cc9497/32.png) [@YamatoTwinkie](https://boards.straightdope.com/u/YamatoTwinkie)\ **Post date:** [May 14, 2009, 11:21pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/29 "2009-05-14T23:21:15Z")
> [@RickJay](#): > > What radiated heat? > > Again… heat doesn’t radiate through a vacuum. The only way the heat of the surface gets to you is if you touch it, e.g. through your boots. Nonsense. Every material above absolute zero radiates energy, vacuum or no. > **[Stefan–Boltzmann law](https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law)** > > The Stefan–Boltzmann law, also known as Stefan's law, describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature. It is named for Josef Stefan, who empirically derived the relationship, and Ludwig Boltzmann who derived the law theoretically. > For an ideal absorber/emitter or black body, the Stefan–Boltzmann law states that the total energy radiated per unit surface area per unit time (also known as the radiant exitance) is directly proportional to th... ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [May 14, 2009, 11:57pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/30 "2009-05-14T23:57:17Z")
> [@KneadToKnow](#): > > You do know that the ~ symbol means “approximately” not “negative,” right? > > 🙂 \ Of course, it’s a tilde! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 15, 2009, 12:11am UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/31 "2009-05-15T00:11:56Z")
To the extent that heat’s a problem, body heat inside the suit is probably a bigger problem than anything external. ---
**Author:** ![Oukile](https://avatars.discourse-cdn.com/v4/letter/o/13edae/32.png) [@Oukile](https://boards.straightdope.com/u/Oukile)\ **Post date:** [May 15, 2009, 7:14am UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/32 "2009-05-15T07:14:52Z")
> [@constantine](#): > > A recent episode of the discovery channel show “How do they do it” discussed manufacture of spacesuits, and they discussed the use of chilled liquid for cooling. They said this use of chilled liquid was a relatively recent invention, and that the apollo astronauts said that wearing one of the apollo suits on the moon was about like being in a sauna. I once had a chat about this with some NASA guys. Of course the suits are refrigerated. The main problem is that there is always a face of the body which is exposed to the sun, and which gets quite warm, and one which is not, which tends to freeze. As a results, you end up sweating in one part of your body and being almost frozen on some other parts. Not fun. Being around in space in a space suit is certainly a great experience in many respects, but it is a very exhausting one. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [May 15, 2009, 1:48pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/33 "2009-05-15T13:48:24Z")
> [@bup](#): > > The astronauts landed at local morning, before the surface got raging hot. Incidentally, landing just after local morning also meant that the astronauts had strongly oblique lighting to highlight surface irregularities as the LEM was being maneuvered for landing. ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [May 15, 2009, 5:50pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/34 "2009-05-15T17:50:24Z")
Doesn’t radiative heat transfer require a medium to pass through? The way I understand it, radiation _energy_, like light from the sun is contained in the photons, but once it contacts and transfers energy to the molecules of the moon’s surface, that energy can only be transfered to something else (like an astronaut) by conduction, convection or radiation. If the astronaut is standing still on the moon, then there is no atmosphere, and no wind, so convection is out. The lack of atmosphere would mean, I think, that a hot moon rock 1 meter away from the astronaut would not be able to radiate heat to the astronaut since there is nothing between them to carry that energy from one body to the other (it is not the same as the heat from the sun, since the rock won’t radiate photons). That only leaves conduction, and that requires direct contact to the moon, and is proportional to the surface area of the bottom of the spacesuit’s boots, and protecting against 100C via insulation seems pretty easy. Am I on the right track here? Although I’m thinking this simplifies things a little too much, since this only deals with the interaction of the astronaut and the moon, but the photons from the sun will also hit the astronauts directly. This can (and is) dealt with in the same way the spacesuit handles an EVA, though, and that’s clearly been managed. _ponders_ ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 15, 2009, 6:02pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/35 "2009-05-15T18:02:19Z")
> [@](#): > > The lack of atmosphere would mean, I think, that a hot moon rock 1 meter away from the astronaut would not be able to radiate heat to the astronaut since there is nothing between them to carry that energy from one body to the other (it is not the same as the heat from the sun, since the rock won’t radiate photons). The rock emits photons through exactly the same process that the Sun does. It’s just that, because the surface of the Moon is much cooler than the surface of the Sun, the photons emitted will be longer in wavelength, infrared rather than visible. ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [May 16, 2009, 5:58pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/36 "2009-05-16T17:58:23Z")
Hmmm, you’re right. I should have known that. Thanks for pointing it out to me! ---
**Author:** ![NinjaChick](https://avatars.discourse-cdn.com/v4/letter/n/71c47a/32.png) [@NinjaChick](https://boards.straightdope.com/u/NinjaChick)\ **Post date:** [May 16, 2009, 7:30pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/37 "2009-05-16T19:30:27Z")
> [@Oukile](#): > > I once had a chat about this with some NASA guys. Of course the suits are refrigerated. The main problem is that there is always a face of the body which is exposed to the sun, and which gets quite warm, and one which is not, which tends to freeze. As a results, you end up sweating in one part of your body and being almost frozen on some other parts. Not fun. > > Being around in space in a space suit is certainly a great experience in many respects, but it is a very exhausting one. Cold hands, in particular. In the 90’s NASA spent a decent chunk of change coming up with gloves with a battery-powered heating element in them, because astronauts on EVAs were having problems with their hands literally freezing. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [May 19, 2009, 7:53pm UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/38 "2009-05-19T19:53:58Z")
The hands are a particularly challenging design item, because they have lower thermal mass so they retain heat less than, say the torso. Because they are required to have more articulation, so the number of layers is fewer and gloves thinner. And because they are extremeties, which means a proclivity for less blood flow and corresponding body heat. Also, the gloves can be tiring to use because, even though they have constant volume joints (and thus are not as difficult to use as the Moon Landing Hoax proponents would have you believe), they still do require finger strength for prolonged activity. Overall spacesuit thermal regulation is controlled by 1. the suit being white, reflecting a lot of incoming radiation. 2. the suit having a sublimator, which allows water to sublimate away, which cools water in the heat transfer system. Balancing the interior temp to be comfortable is a challenge because exertion causes more body heat, different sunlight amounts means less radiation heating, and normal variations in body comfort levels. There are control knobs that each crew member sets individually and can adjust at will, but these only handle gross adjustments in cooling liquid flow rate, glove heating, air flow into helmet, etc. ---
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [May 20, 2009, 2:32am UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/39 "2009-05-20T02:32:08Z")
Discovery Science has a series (that they repeat fairly often as it is more or less new) called Moon Machines. One of the episodes is about the space suits. It more or less says what has already been told here, but it doesn’t hurt to hear it with pictures and actual footage from those days when. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [May 20, 2009, 3:00am UTC](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438/40 "2009-05-20T03:00:17Z")
According to the 1958 documentary _Missile to the Moon_, stepping into direct sunlight could be extremely hazardous, as shown in [official footage](http://www.youtube.com/watch?v=lKQo8mKTEWk). [Previous page](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438.md?page=1) [Next page](https://boards.straightdope.com/t/how-did-the-astronauts-cope-with-the-drastic-temperatures-on-the-moon/496438.md?page=3)