3 ms·

"Mass driver".

rbanffy 6y ago
The 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 ago
  I 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 ago
    This all reminds me of "The Moon is a Harsh Mistress"
- mrweasel 6y ago
  Couldn'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 ago
    This 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 ago
  I 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 ago
To 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.

"Mass driver".

The 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 ago
I 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 ago
  This all reminds me of "The Moon is a Harsh Mistress"
mrweasel 6y ago
Couldn'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 ago
  This 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 ago
I 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 ago

To 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.