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Comment by obblekk | Hacker News Reader

10,000Gs is probably too much for electronics, but fine for raw steel. Probably useful to have a low cost way of shooting a lot of working material into space.

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They made _vacuum tubes_ survive 20,000g during WWII [1]. Modern military applications have guidance computers packed into individual bullets [2]!

[1] https://en.wikipedia.org/wiki/Proximity_fuze#Improvement_in_...

[2] https://en.wikipedia.org/wiki/Smart_bullet

The problem with this is if you toss a chunk of raw steel, no matter how fast or at what angle, it will always simply fall back down [1]. The minimum payload for this system absolutely requires a (extremely robust) rocket engine and propellant and avionics to circularize the orbit at apogee. That's the only way to achieve orbit. That puts a disappointingly high floor on the cost per launch and launch rate.

[1] Technically, escape velocity is also a possibility. But it's not a useful one, as the payload is still lost.

That only holds true assuming a 2-body (earth and rocket) system - add in forces from the sun or from the moon and you can actually achieve orbit with only a single surface level impulse, although it does require some pretty precise aim.

It would be super cool to use the moon to circularize the orbit. But the orbit you'd get wouldn't be super useful, probably. I wonder about stability as well. And the practicality of achieving the velocity to reach that high, and aiming that precisely. It would be really cool to see some analysis of that.

Another out-there idea would be to shoot things at a space station that had a giant catcher's mitt or something. Would it be possible to design a decelerator that would work? And to hit it precisely with a dumb projectile from the ground?

A third possibility would be to recover and reuse the rocket engines en masse. Not sure how it could be done in a way that was cost effective though.

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