Space is cold. Really cold. It’s also hot. Really hot. Or more accurately, space is empty. Really empty. It’s a common misconception that being exposed to the vacuum of space means a quick and painful death-by-quick-freeze, à la Danny Boyle’s excellent (but not entirely accurate) Sunshine.
The reality is a little less exciting, as without an atmosphere for your body heat to leak into by convection, you can only lose heat by thermal radiation. As explained in this Quora article, it would take a couple of hours to reach hypothermia-levels of cold in the shade, and in the sunlight you could actually overheat if you were exerting yourself (perhaps by panicking because you’re FLOATING FREE IN SPACE).
So what does this mean for your space station? Well, it means you need to be careful about the amount of heat you’re generating, versus the amount of heat you’re radiating. Pretty much everything on board your station generates heat. Computers, research equipment, food heaters, even your astronauts are pumping heat into the atmosphere of your station. Without a way to get rid of that heat, your station will get hotter and hotter, until machinery has to be shut down, computers overheat, and your astronauts are able to do less and less work. If it gets hot enough, astronauts will have no choice but to evacuate the station via docked resupply vehicles or escape pods.
How do you avoid overheating? Radiators.
No, not those radiators. These radiators:
Though considerably more expensive, these radiators work in a very similar fashion to the ones you may have in your home. A liquid coolant is pumped around a loop between the interior of your station, and the external cooling plates of the radiator. This increases the available surface area for heat to radiate out into space, and reduces the internal temperature of your station. Bigger and more efficient radiators can deal with more heat, so researching these technologies is essential to prevent overheating as your station becomes more complex.
But what about heat flowing between the different parts of your station? Watch out for the next Dev Blog to find out!