@Mae This isn't really my field of expertise, but I do think it's misleading to say that space is cold. Temperature is a property of matter, and space is fairly well known for being notoriously devoid of matter; therefore space doesn't *have* a temperature as we normally think of the concept.Also, a thermos bottle uses a far worse vacuum than what you'd get in a stable Earth orbit, and functions as a pretty good heat insulator. @ariadne