[reaperducer]

Normally, foam contains a lot of air. But that kind of foam will blow itself apart in a vacuum.

In the video, Thermal Protection System Engineer Betsy Congdon says it's 97% "air."

I can't say whether it's actually air, or she's simplifying things for the general public or not.

She also says twice that "water" is used in the radiators. But I'd have to believe that NASA's using something that absorbs/dissipates heat a little more efficiently. Perhaps whatever it is will end up in desktop gaming rig cooling systems eventually.

[zaarn]

They used deionized water, not unusual for gaming rigs either.

The temperature range is about 15C to 125C, at high pressure this is most ideal for use with water and water itself is a rather good coolant.

[petre]

The only substance that can transport more energy than water that I know of is ammonia. But it's quite corrosive and it has to be pressurized at 50-100 bar to make a difference.