Short · Space
Why build a 10 km space gun?
Ashlee Vance asked Neal Stephenson about it: Longshot, in Oakland, wants to build a space gun 10 km long, pushing a payload down a tube with blasts of gas. Why so long? A short barrel has to shove hard: their ~20 m test gun hit Mach 4 with thousands of g. Spread the same push over 10 km and near-orbital speed costs only a few hundred g. Rugged satellites can take that. People can’t: they would need a barrel about 1,000 km long.
Opens Space Gun Lab. Change the same thing yourself.
Transcript
Ashlee Vance asked Neal Stephenson about this: a space gun ten kilometers long. Longshot, in Oakland, wants to build one, pushing a payload down a tube with blasts of gas. Why so long? A short barrel has to shove hard. Their test gun, about twenty meters long, hit Mach four with thousands of g. Now stretch the barrel. At ten kilometers, the same push is spread out: near-orbital speed for a few hundred g. Rugged satellites can take that. People can't. Stretch the barrel yourself at Explainer Tools dot com.
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More ways to space
A long gun is one of four launch ideas Neal Stephenson talked through on Core Memory. The guide compares all four, and the other three films are here.
- Topic guideWhat are the ways to space besides a rocket from the ground?Towers, slings, space guns and whips: what each buys, what each costs, and why rockets won.
Short · 39 secondsWhy launch rockets from a 20 km tower?Neal Stephenson’s tall tower: start above 94.6% of the air and a single-stage rocket carries twice the payload.
Short · 36 secondsHow does SpinLaunch throw rockets into space?SpinLaunch throws its rockets: double the speed and the force quadruples, to about 10,000 g.
Short · 39 secondsWhy does a whip crack?A whip crack is a tiny sonic boom, and Stephenson’s giant steel whips would give a rocket a head start.