International Space Station Experiment

[yakko]

I was just thinking isn't true that in space, whilts in the shadows, the temperature is -270 C.
Perhaps we could convince NASA, (or some space tourist) to place
a system outside. It be interesting to see the benchmarks.

However, because of the vacuum of space the hard disk might have
to be connected through firewire technology or something similar.

Cheers

[Hoot]

It would be interesting to know how his fans do in a vacuum. ;D I bet Rad Hard PCs cost a pretty penny!

Hoot

[Phil]

Why would the hardisk being conected via firewire make any differance to it being in a vacuum?

And as for the cpu think, it would burn it's self out as there would be no medium to absorb the heat from the heatsink, you can ignore the amount of heat lost by radiation it would not be enough to cool the cpu.

[asmodean]

But the ambient is so low... It would propably freeze to death. :D

[Phil]

the ambient what? the cpu would be generating heat which the heatsink would absorb, it would start off at a low temp but because there is no medium to absorb the heat it would slowly heat up and not be able to loose heat (apart from the miniscule amount lost by radiation)

[Fink]

99.98% of cooling (under atmosphere) comes from transfer from the heatsink material to the air. In space, the only way to expell heat is via radiation - radiative cooling - and it is not very efficent.

[yakko]

Ah yes I forgot about the lack of convective cooling .
However, with no gravity what stops you from sticking a heatsink the
size of toaster onto the chip (granted the initial contact point would
need to taper to the chip size). If the surface area exposed was large
enough, then perhaps radiant loss would equal the heat generation.

Hmmm, there must be some physicist reading this board; perhaps
one of them can calculate the exposed surface area required for radiant
cooling in the vacuum of space (assume heat sink is copper, and
the power dissipated by the chip is 50 Watts).

[William]

don't they have some sort of water cooling rig for the external parts to help with the hot side and the cold side?

[Daniel ~]

I'm betting this will be one lonnnnng thread":O}

Wouldn't the ambeint temps suck heat from the CPU, even with out a heatsink? I mean I produce a fair amount of heat, but woudn't last long in a deep freeze. Just asking":O}

[yakko]

To understand the difference in conductive properties of air vs space,
consider the difference between air and water. You can stay outside
in 10 C (50 F) for several hours;however, unless you're a marathon
swimmer, you'll be become hypothermic inside of 20 minutes in
water of the same temperature.

However, radiant heat loss does occur. Consider the movie Apollo
13 during the trip back from the moon (3 days) the cabin heater
was not turned on, during this time the cabin temp. dropped to near
freezing (even with 3 people each generating about 50 watts).
Assuming the energy imparted on the sunny side of the capsule is
dissipated on the leeward side, its clear that the surface area of
the capsule was large enough to dissipate the 150 watts the crew
was generating plus the heat initially in the cabin. Finally , the
capsule was not made of copper which transfers heat well.
(Note, I'm assuming the movie accurately depicts this cabin cooling.)

Therefore, I feel that it would be possible to cool the chip through
radiant heat loss by mounting a copper heat sink the size of a toaster.
Additional surface could be obtained by fixing to the space station.


Cheers

[Phil]

you put put as good a heatsink as you want and it would not be good enough, it just won't radiate enough heat, it's not like people loosing heat in space, people don't constantly generate heat the same as a processor would, you eventually cool down where as the processor will continue to heat up as it is operating and I much doubt that a heat sink could be designed to radiate heat well enough.

[yakko]

Phil the average person constantly generates between 25 and 50
Watts, a processor constantly generates 50 to 100 Watts I don't
understand your arguement.

[Shadow ÒÓ]

you NEED some type of convection for cooling. No question. If it's air or water or whatever. A vacuum has no (or almost no) type of "sweeping the heat away".

In air at cold temps, the body would retain heat better.

In water it would lose body heat faster (hence water cooling).

I a vacuum (such as space) there's not much to pull the heat away.

[asmodean]

About that watercooling... The water would have to be in a block, like in an atmosphere. Wouldn't the water freeze, as the block would be very cold? Just dump some water in space and it freezes to crystals, right?
I'm propably wrong on this one, though.

Possibly the best cooling solution so far has been attaching the chip to the space stations hull. You could attach some dual-palominos or 8-way SMP-P3's/P4's there a very huge amount.

The only problem I see with this whole idea is those high-speed particles & mini-meteors, as they would punch thru the mobo and other accessories like a hot knife thru butter. Propably some titanium-alloy shielding would take care of that.

[Phil]

yakko (May 19, 2001 08:06 p.m.):
Phil the average person constantly generates between 25 and 50
Watts, a processor constantly generates 50 to 100 Watts I don't
understand your arguement.

all I am trying to get across here is that in space with radiation being the only way the cpu can loose heat it would not be enough, even if you could design a brilliant heatsink that somehow radiated enough of the heat off it would work better in an atmosphere where it could convect heat as well

[speedy4500]

This is interesting....

To all who think that a human body would freeze in outer space: the opposite actually happens. The blood BOILS because a) the heat cannot escape, and b) the super low pressure allows liquid to boil easier. I don't know what this has to do with overclocking (maybe never use water cooling), but a Russian cosmonaut was exposed to outer space for a few seconds and this is how it is known.....stupid Russians :-)

[Phil]

well there you go as long as what speedy4500 is correct then humans don't loose heat for the same reason I have been stressing that a cpu wouldn't be able to keep cool

[asmodean]

Forgot that zero pressure, thanks! Ugh, you propably can't run a computer in pure space. Possibly in the outmost layers of our atmosphere?
How high is the ISS located, anyhow? Still in the atmosphere?

[quiksilvr00]

The Earth's atmosphere is quite big. The space shuttle and the ISS are both technically in the "atmosphere" of earth. Space also doesn't really have a temperature. It's both hot and cold. I believe that you need something like air to have a temperature. A medium of some sorts. Also, what happens when the orbit has you facing the sun. The chip probably would instantly be cooked. Phil Plait runs a good site, www.badastronomy.com and he's got some info about what the temperature is like in outer space and also we need to know the difference between heat and temperature. Temperature is how hot something is, and heat incorporates temperature and how well the tmperature can be transferred from one thing to another. So the actual temperature at which that chip is running doesn't matter so much as how well that temperature is tranferred off the chip to something else.
www.badastronomy.com/bitesize/heat.html

just my $.02

[yakko]

[quote]quiksilvr00 (May 22, 2001 05:15 p.m.):
.
doesn't really have a temperature. It's both hot and cold. I believe that you need something like air to have a temperature. A medium of some sorts. Also, what happens when the orbit has you facing the sun. The chip probably would instantly be cooked. Phil Plait runs a .
.
.


Hmmm, what about ether as a medium ;) To avoid cooking the chip
its always kept in the shade. I'm a little surprised no has
mentioned problems caused by ionized particles especially during
solar activity.

Phil, I'm still a little confused by your arguements. Specifically can u
explain why the cabin of Apollo 13 cooled down to near freezing,with
three astronauts in it generating a total of 100 - 150 watts, whilst
surrounded by a vacuum. Where did this 100 - 150 watts of heat
go ?

[bdf24]

WOW!!!

This is some pretty heavy s!@#!

There was air in the cabin of the space craft. Would that have anything to do with it getting down to almost freezing? If so then instead of having a normal heatsink just stick a sealed alloy container to the cpu core. maybe the air on the inside would be enough to keep the alloy cold and cool the cpu.

Just a thought.

[yakko]

Let me be more specific. Why did the cabin cool down ? The heat
went somewhere. The bodies of the astronauts radiated the heat
generated by their bodies into the air of the cabin. The heat (energy)
in the air was then transfered to the walls of the cabin, and eventally
to the surrounding metal of the spacecraft. Eventally, this heat was
radiated into space. Now, its possible the cabin cooled down, not
because of radiation into space, but, because of transfer of energy
to the liquid fuel and oxygen containers, kepted at -70 C, which acted
as a heat sink.

[William]

ok, i am interested in this enough to ask my physics professor this tomorrow. He's got a PhD and he is one of the smartest people I know so hopefully I can understand what he tells me!

[yakko]

Ask your professor about ether (this concept was popular about 100 years ago.)

[Clemson Physics Geek]

Quiksilvr00 was right in his statements above. There's a difference between temperature and heat. Temperature is just a measure of the amount of vibrational energy in each atom or molecule (not exactly, but good enough for this discussion). Heat is a physical quantity; its a form of energy. The upper atmosphere has a very high temperature, but because the air is so thin it doesn't actually have a lot of HEAT. BTW, this whole discussion is kind of mute b/c a normal computer chip probably wouldn't last very long in space...X-rays and Gamma Rays do nasty things to transistors.

[yakko]

See post 21, regarding ionization.

[William]

alright, well I got some basic explinations going here, forgot to ask my physics prof, DOH! Basicly, asking one of good friends who is good at Physics, Space is a conductor of cold is what he told me, which is what the physics prof. told him. Going to go ask him though monday hopefully. I am very very interested in this.

[Hoot]

yakko (May 26, 2001 11:16 p.m.):
See post 21, regarding ionization.

see post #2, what do you think Rad Hard means? ;D
I worked in Aerospace for 15 years.

On the lighter side, ponder this:

"In Space, nobody can hear your Delta scream". :D

Hoot

[SleepyKat]

External equipment on ISS is regulated. Cooling is done thru Ammonia cooling tubes and heaters for those components. Now as for inside the station, remember hot air rises but there is little/no gravity so the heat just forms a blanket around the heat producing component and cooks it. All of the equipment has fans inside to force air flow. The rack structure has access to moderate and cold fluid loops for fuild cooling. The air is regulated thru cold plates. Rad hard chip are more for deep missions. And you real can't stop SEU from highly charge particles.

[Phil]

yakko (May 24, 2001 10:56 p.m.):
Ask your professor about ether (this concept was popular about 100 years ago.)

Ether is presently just a theory, and in this theory the medium only conducts electro magnetic radiation which still doesn't allow for convection only radiation.

[yakko]

About 100 years ago scientists proposed that there must be some sort
of medium in space to explain the propogation of electro-magnetic fields
(i.e. wave model). This theory is no longer in fashion. The comment was
ment to be more of a joke (I guess the wink icon is not very illuminating).

Thanks Hoot for explaining the term Rad Hard PC, with all the wild product
labeling it didn't occur to me that you were speaking about radiation.

[yakko]

SleepyKat (May 27, 2001 12:17 a.m.):
External equipment on ISS is regulated. Cooling is done thru Ammonia cooling tubes and heaters for those components. Now as for inside the station, remember hot air rises but there is little/no gravity so the heat just forms a blanket around the heat producing component and cooks it. All of the equipment has fans inside to force air flow. The rack structure has access to moderate and cold fluid loops for fuild cooling. The air is regulated thru cold plates. Rad hard chip are more for deep missions. And you real can't stop SEU from highly charge particles.


How does the heat get vented out of the spacecraft ? Correct me if I
wrong, but, even a fridge has a radiator (heat sink) which helps vent
the heat inside the fridge to the outside.