Wasn't the "super cheap fusion launch" predicated on discovering a non-Newtonian rocket engine? As long as you're suffering under the third law the idea of a super cheap launch is a pipe dream. This is also why concepts of reaching distant solar systems by maintaining 1G of thrust for the entire trip don't work. Plug the numbers for that into the rocket equation and even with absurd ISP values it requires more mass than is available in our solar system for a trip to even just Proxima Centauri.
The only maybe possible exception would be to pump so much energy into your reaction mass that it gains a significant amount of mass from relativity, but even that is engineering in the "it's probably easier to build a space elevator" realm.
Re:Factories in Space
by JumpCrisscross on Tuesday May 30, 2023 @03:12PM
(#36129188)
> response that just hand-waves a bunch of really hard problems or invents tech that doesn't exist
The tyranny of the rocket equation is irrelevant to the problem of extraterrestrial manufacturing, at least in the short term. It’s all ISRU.
> Has there been legitimate significant progress on orbital guns or space elevators since 2012
Actually, yes. I’m sceptical of SpinLaunch. But they are making real progress on the technology, even if they aren’t the ones to complete the package to orbital delivery.
The response that just hand-waves a bunch of really hard problems or invents tech that doesn't exist.
I get it, HN has a lot of tech-optimists, but these responses are very tiring. Has there been legitimate significant progress on orbital guns or space elevators since 2012?