Skylon is a British company trying to construct an air breathing SSTO. Apparently that's an open question.

I think the battery is a large part of it. Since they're much less energy dense than gas they take up the entire bottom of the car.

Probably Project Hail Mary, although I don't think there's a wrong choice.

It's pretty good so far, and was exactly what I was looking for. Thanks.

I've read it, along with Artemis and Project Hail Mary. That's a good suggestion though.

Recommend me some good hard sci-fi. Not in the background either, I want it to be full of long rambling explanations about how exactly things work. I'm a fan of Peter Watts, Greg Egan, and Charles Stross. If you're familiar with that last author, think along those lines except with more nuanced (better) characters. I've read The Expanse, so don't bother with that one.

Pedantic note: proxima b is far from the most earthlike planet we've discovered.