[ihehqrko] supergun space fountain

at first glance, a giant gun seems not a very practical method for space launch, because very few payloads, certainly not humans, can survive that kind of acceleration.

in contrast, a space elevator, if we could build one, would be a very practical method of getting humans and other fragile cargo to outer space.  (a space elevator is not so great for putting satellites into low earth orbit because it only provides vertical height not horizontal speed.)  one of the most promising designs for a space elevator, promising because it does not require materials with currently unachievable amounts of strength, is a space fountain.  and one of the ways to build a space fountain is a giant gun launching pellets up a tall evacuated tube to space.  the tube does not need to be made of an impossibly strong material because it is actively held up by skimming momentum (somehow) from the pellets shooting upward inside it.  humans then leisurely climb up the outside of the tube to space and beyond.

(at the top of the space fountain, the pellets fall back down to earth.  for energy efficiency, their falling energy at the bottom should be recovered or reflected to launch pellets up again.)

space elevators seem the only realistic way to migrate all humans off the planet before the gradually warming sun boils all water on earth.  alternatively, maybe we can get nuclear pulse propulsion to work, but rockets with radioactive exhaust will be extremely messy near the earth's surface.

(maybe we can increase albedo or play cosmic pinball to survive the warming then red giant sun, but we would still need to get off planet to survive white dwarf sun.)

therefore, the executions of both the world's leading scientist on giant guns and his patron, with the chilling effect those assassinations have on anyone considering continuing such work in the future, may have tremendous consequences on the long-term outcome of our species and survival of intelligent life in the universe.  perhaps that was precisely the moment when humanity went extinct: "Israel, you fool!  you've doomed us all!"