Once outside the atmosphere and up to speed, rockets are actually pretty efficient. The space shuttle main engines achieved 15% propulsive efficiency if I remember correctly; this is better than many land vehicles
Yes, but getting out of the atmosphere is really inconvenient.
Do you have a citation or a back of the envelope for the statement about launch loops having such large power requirements? I don’t think I’ve seen that before, and I’d be interested in seeing that.
100 billion tons/year may sound like a lot but you really do need to launch that much cargo in order to recuperate construction and operation costs. The 0.1 degree heating cited on that page is a bit optimistic since it doesn’t take into account secondary effects.
Is the claim that launching a ton of payload by launch loop heats the earth more than launching a ton by rockets? That is very hard to believe. To a first approximation, the energy savings of the launch loop are heat savings.
Or is the claim that launching enough payload to make a launch loop worthwhile is too much heat, either way?
Yes, but getting out of the atmosphere is really inconvenient.
Do you have a citation or a back of the envelope for the statement about launch loops having such large power requirements? I don’t think I’ve seen that before, and I’d be interested in seeing that.
I don’t remember exactly where I read that, but here’s a page with some power calculations: http://launchloop.com/LaunchLoopHeating
100 billion tons/year may sound like a lot but you really do need to launch that much cargo in order to recuperate construction and operation costs. The 0.1 degree heating cited on that page is a bit optimistic since it doesn’t take into account secondary effects.
Ouch. Yeah, that’s not reasonably viable.
What, exactly, is the claim?
Is the claim that launching a ton of payload by launch loop heats the earth more than launching a ton by rockets? That is very hard to believe. To a first approximation, the energy savings of the launch loop are heat savings.
Or is the claim that launching enough payload to make a launch loop worthwhile is too much heat, either way?
Good point. Hmm, now I’m confused.