I want to nitpick you here but a thermos is specifically good at insulating because not only does it have a vacuum gap, it's also got two layers of metal (inner and outer) to absorb and reflect thermal radiation.

That specific aspect is NOT true in space because there's nothing stopping thermal radiation.

Now you're correct that you can't remove heat by conduction or convection in space, but it's not that hard to radiate away energy in space. In fact rocket engine nozzle extensions of rocket upper stages depend on thermal radiation to avoid melting. They glow cherry red and emit a lot of energy.

By Stefan–Boltzmann law, thermal radiation goes up with temperature to the 4th power. If you use a coolant that lets your radiator glow you can conduct heat away very efficiently. This is generally problematic to do on Earth because of the danger of such a thing and also because such heat would cause significant chemical reactions of the radiator with our corrosive oxygen atmosphere.

Even without making them super hot, there's already significant energy density on SpaceX's satellites. They're at around 75 kW of energy generation that needs to be radiated away.

And on your final statement, hyperloop was not used as a "distraction" as he never even funded it. He had been talking about it for years and years until fanboys on twitter finally talked him into releasing that hastily put together white paper. The various hyperloop companies out there never had any investment from him.

> a thermos is specifically good at insulating because not only does it have a vacuum gap, it's also got two layers of metal (inner and outer) to absorb and reflect thermal radiation.

Not necessarily. There are many modern thermos "cups" that are just a regular cup, except with two layers of glass and a vacuum. Even the top is open all the time. (e.g. https://www.ikea.com/us/en/p/passerad-double-wall-glass-8054... )

It's still good enough to keep your coffee hot for an entire day.

It is well known that Musk primary reason to push Hyperloop was because he didn’t want them to build a high speed rail for some reason:

> Musk admitted to his biographer Ashlee Vance that Hyperloop was all about trying to get legislators to cancel plans for high-speed rail in California—even though he had no plans to build it.

https://time.com/6203815/elon-musk-flaws-billionaire-visions...