Heat is so easily retained in space that when the Shuttle launched they only had 4 hours to open the cargo doors to expose the radiators or the cabin and electronics would overheat and they would have to scrub the mission. They never had to scrub for that reason though.
Comment on Made in space? Start-up brings factory in orbit one step closer to reality
Auth@lemmy.world 3 weeks ago
Pretty interesting. How come they can get 1000c in space but not on earth? Doesnt the vacuum of space make it hard to retain heat?
atomicbocks@sh.itjust.works 3 weeks ago
Decq@lemmy.world 3 weeks ago
The article doesn’t state they can’t reach that temperature down on earth, and many processes do. It’s really not the jist of the article. Space manufacturing is interesting for the micro-gravity and better vacuum/less contamination. .
Gsus4@mander.xyz 3 weeks ago
Vacuum is a perfect thermal insulator. The only real losses are radiative.
Auth@lemmy.world 3 weeks ago
I’m completely unaware of the science around it all but none the less its exciting stuff, i hope to read more about it as things progress.
UniversalBasicJustice@lemmy.dbzer0.com 3 weeks ago
There are three modes of heat transfer; conduction, convection, and radiation.
Conduction happens when two bodies at different temperatures come into contact with each other. The total heat transfer depends primarily on the difference in temperature, contact surface area and time spent in contact.
Convection takes place when a fluid (I.e. a gas such as air or a liquid such as water) comes into contact with another body. Here, again, heat transfer depends on difference in temperature, contact (“wetted”) surface area and time in contact which is primarily dictated by how fast the fluid is moving over the body.
On Earth we generally leverage these two modes. An example of mixing the two modes is a CPU heatsink and fan setup. The heatsink conducts heat away from the CPU and is (usually) distributed throughout several extended surfaces I.e. fins. The fins increase the surface area in contact with air, enhancing the rate of heat transfer.
Now, we can’t really take advantage of those in space. The lack of an independent physical medium means the heat ultimately has no where to go; this is known as a “closed system”. So if we generate or store enough heat in a body subject to the void of space without promoting radiative heat transfer, that heat will more or less stay put.
Radiative heat transfer is fucked up. Everything above absolute zero radiates heat. You mostly can’t see this exact for one glaringly obvious example; the Sun. Sol is so fucking hot that it heats the Earth through the vacuum of space purely via anger aka photons. And thanks to the miracle of science, you radiate anger right back at it.
Explaining radiative heat transfer further is outside the scope of this reply and will be left as an exercise to the reader.
I hope I explained this well enough for you or other readers to impart a ‘basic’ idea of a complex engineering discipline that I adore. I’m absolutely willing to answer any questions.
feannag@sh.itjust.works 3 weeks ago
Are you sure it’s engineering you adore. Left as an exercise for the reader? That’s physicist speak.
Blisterexe@lemmy.zip 3 weeks ago
Maybe a stupid question, but you’d have to have something to hold the really hot thing, right? And obviously you’d need a bunch of stuff connected to the furnace to keep it in orbit and supplied with energy. So in that case wouldn’t the heat from the thing being heated spread to the rest of the satellite anyways? Like, clearly you can’t just use non-conductive materials because then we’d already have that on earth.