eli5: if space is virtually empty, does a space shuttle stay hot from when it exits the atmosphere because there’s less particles to absorb the heat? Or does it do the opposite and cool rapidly?

Question

I’m just curious as to the process and behavior of the surface temp of a shuttle once there’s virtually no particles in contact with the craft.

I’m aware space is cold due to the absence of matter,

But does a space shuttle take a much longer time frame to cool down with less matter available to transfer the heat of the craft to, or does the lack of matter cause the shuttle to cool rapidly?

In: 141

Answer 1

Space is called cold because the temperature of the cosmic microwave background (basically the energy coming from in between all the stars) is very low. But because there’s so little matter at orbital altitude and even less the deeper you go into space, there’s a considerable insulating effect. You can’t use conduction or convection to get rid of heat, so you can only radiate it. That means objects in space tend to take a long time to cool down, or since we’re in a solar system, may actually heat up to a failure point just because of the sun.

Heat management is a critical component of spacecraft design. Since you mentioned the shuttle, it had advanced materials that were designed to shed heat extremely quickly. I don’t know if they were as effective in space as they were as a reentry heat shield, but in general yes, you want as much ability to radiate excess heat as possible.