[close04]

I just imagined that for an object sent to the Sun they'd want to... overdo it a little. Go for something synthetic that would behave even better or would save 1/2 Kg.

I'm just the inquisitive type. Explaining that something is used always makes me wonder "why not something else" :).

[tesseract]

Water has a higher specific heat than most substances, and probably the highest of anything that's a liquid across the operating temperature range for the electronics.