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I still wonder about another radical idea: launching payloads (not people obviously) via a long ramp with some kind of magnetic accelerator and flinging them in
by coldcode 6y ago
I still wonder about another radical idea: launching payloads (not people obviously) via a long ramp with some kind of magnetic accelerator and flinging them into orbit. I forget what this idea was called.
- throwanem 6y ago"Mass driver".
- rbanffy 6y agoThe ramp needs to be very long or we'd need to build a very rugged spacecraft - enough of its brains and propulsion would need to survive the acceleration and the aerodynamic losses on the way up in order to circularize the orbit and not cross the ground on its way back. Which brings a very scary failure more - being hit by the payload that is mostly dead, but coming back to the ground at near orbital speeds.
- growlist 6y agoI think the hardening is pretty well understood - just fill any sensitive electronics etc. with resin and it's pretty much solved. But the heat problem certainly is not, and obviously humans, not being particularly amenable to being filled with protective resin, would be completely pulped without ridiculously long ramps. I'm interested to know whether anything ever comes of this: https://www.wired.com/story/inside-spinlaunch-the-space-industrys-best-kept-secret/ https://www.wired.com/story/inside-spinlaunch-the-space-indu... I'm sure I recall reading something on a forum somewhere from an anonymous former employee that claimed Spinlaunch was a mess and would never work.
- csours 6y agoThis all reminds me of "The Moon is a Harsh Mistress"
- mrweasel 6y agoCouldn't you park a "space truck" in orbit, with a normal rocket, and just have the payload be a dumb container. Then shoot the container into orbit using the mass drive and pick it up with the "truck". It's still might be no good for scientific equipment, but for food and things of that nature might be okay.
- jk7f 6y agoThis sounds like a lot like the concept called a "sky hook", you can even have it rotate and use it to fling stuff further into space. Isaac Arthur has some nice videos about it on YouTube.
- mLuby 6y agoI wouldn't worry about that "nearly orbital" failure mode: rockets are sometimes remotely "dissembled" during flight (boom!) in case of guidance failure. And even if it went totally dead, only if it passively orients itself for a safe re-entry would it not burn up on its way back.
- bloopernova 6y agoTo get into orbit you need 2 pushes. One push upwards puts you at altitude, the other is sideways to make you fall around the Earth and not come back down. If you have one big push, you escape the Earth's gravitational pull. If your push isn't big enough, you fall back to the ground.
- valuearb 6y agoMass accelerators aren’t useful because the atmosphere limits their final velocity. You’d need to have an enclosed vacuum tube with an exit north of 20,000 feet. There have been proposals to build something just like that with a “plasma” door at the end that can snap open and closed to keep the atmosphere out of the tube. It still can’t get anywhere near orbital velocity, so the plan is to use it to accelerate a second stage that uses rocket engines after it is released to provide the rest of the orbital DeltaV. The Problem is rockets are relatively fragile and the high gees and hitting an even thin atmosphere at Mach 6 would destroy them. Look up “spin launch” for an even crazier idea that’s actually funded.