Lack of convection currents in space.

[aman]

I read that simple electronics in space need ventilation fans or they burn up. If they took a standard flashlight into space, would there be a problem with the bulb overheating in the weightless enviroment? I am just curious as to how big of a problem this is.

Just aman

[Cap'n Refsmmat]

If you used it for a long time, you might melt something. But it's not too serious, as far as I know.

[Dave]

They have flashlights on the shuttles, so I'm guessing they must've found a way around it (like writing with ink pens).

[swansont]

Heat loads are a concern, but really only when you are dissipating several Watts. Radiation heat transfer goes as the difference of T⁴, so small amounts of power, like a flashlight, shouldn't be much of a problem. (It's also possible to use flashlights that don't rely on a blackbody source, e.g. LEDs, but I have no idea if there are space-qualified versions of these)

 

Ventilation fans don't do you any good in a vacuum. For larger loads you do liquid cooling, but generally a lot of your engineering is getting the total power consumption down. The limited power available to you drives that at least as much as heat dissipation does.

[Bryn]

Well the bulb in a flashlight is enclosed anyway so evan on earth convection won't cool it down.

 

If you have electronics in the vacum surley the fact that it's only 3 degrees above absolute zero helps cool it down a bit? Unless you have a heated vacuum, which seems a little silly, and tbh how the fuck would you heat a vacuum in the first place?

[swansont]

Well the bulb in a flashlight is enclosed anyway so evan on earth convection won't cool it down.

 

If you have electronics in the vacum surley the fact that it's only 3 degrees above absolute zero helps cool it down a bit? Unless you have a heated vacuum' date=' which seems a little silly, and tbh how the fuck would you heat a vacuum in the first place?[/quote']

 

Any enclosed electronics would not "see" a 3 K reservoir into which it could radiate. Only surfaces that are actually exposes to space would do that. This is the reason that cars tend to frost overnight under clear skies when the temperature is around 0 C, but not under cloudy skies or if they are covered by a tree or car port, etc.

[YT2095]

Well the bulb in a flashlight is enclosed anyway so evan on earth convection won't cool it down.

I couldn`t have said it better myself! )

 

but chill with the lang in the rest of your post though.

[aman]

I was concerned about electronics in an air enviroment since the convection currents I was referring to of hot air rising are not available inside a shuttle. There I imagine even a small wattage usage could melt a circuit over time with no mechanism for heat dissapation. Do they keep the shuttle a little windy to also help with keeping an astronaut from suffocating in his sleep? I know they must have faced and solved these problems long ago but I was just pondering and curious. Thanks for all your input.

Just aman

[Radical Edward]

use a fan I suppose. most computers need them anyway, since convection will not cool my AMD 3.2GHz chip

[YT2095]

I expect much of the heat generated isn`t wasted either. maybe used in some environmental way to maintain cabin temp and stop water from freezing, I can`t see Nasa wasting such a potentialy valuable comodity in the cold of space