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?
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.
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 tyranny of the rocket equation describes the exponential fuel cost of lifting propellant, with propellant, out of a gravity well.
One workaround is non-propellant launch [1], e.g. an orbital rail gun. (Fusion propulsion is still tyrannical because you’re carrying your propellant.) The other is in-situ resource utilisation, i.e. not lifting out of a gravity well.
[1] https://en.m.wikipedia.org/wiki/Non-rocket_spacelaunch