Paint

I saw this piece a few days ago concerning white paint. In theory, it reflects almost all incoming light. So at night the house emits heat as usual and in the daylight, it doesn't take much more. In summer, the balance is reached! No A/C!!

... if you don't open a window. And if birds and squirrels don't poop on the roof. And if there's no rain bringing dust to your house... ever. I am pretty sure the bright white house will run afoul of the HOA as well.

So I don't think this is practical for anyplace on Earth, and we'll throw in Mars. Even our airless Moon has static-electricity to attract the charcoal-grey regolith. But I do wonder about deep space.

As Elon Musk has pointed out, paint has mass so costs money when sending craft up into orbit, and paint-chips become space junk in LEO. Further up, however... white paint looks pretty good. Heat is a major problem in satellites which is why they have radiators. Thinking of ammonia-propellant tanks, lately.

So: paint the satellite on planetside; blast it up anyway (taking the cost); and once in orbit, touch up whatever flakes flaked off.