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I remember when I was younger I had heard this story about the Chinese using primitive fireworks, and even strapping them to a bamboo glider in an attempt to reach the moon. This story probably isn't even true, and I shudder to think of the t/w and isp those fireworks would provide, but would it be possible to strap enough of them together to reach orbit, somewhat similarly to OTRAG, and how ridiculously large would it have to be.

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Very crude back-of-the-envelope math suggests that a rocket of about one million tons -- 300 times the mass of the Saturn V -- could reach orbit on black powder from a specific impulse and mass ratio standpoint. Whether it's possible to structurally assemble a rocket of that size and launch it is questionable, at best.

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  • $\begingroup$ what would the dimensions of such a rocket be(number of stages, height, width, relation between payload capacity and size of rocket)? $\endgroup$ – Reuben Farley-Hall Nov 23 '20 at 5:29
  • $\begingroup$ As per my linked answer to a different question, it's 8 stages, each stage 5 times the mass of the one above it, with a payload of 2.5 tons to orbit from the 1 million ton liftoff mass. Working out the dimensions is left as an exercise. $\endgroup$ – Russell Borogove Nov 23 '20 at 6:50
  • $\begingroup$ @RussellBorogove ...or a 32 gram chip-sat, on a bit over 3-ton (3125kg) rocket (starting off with 1st stage of 2.5 ton - I was checking how much could be shaved off your launch mass by going with smaller final stage that's still not useless, and managed to shave off all of it.) $\endgroup$ – SF. Nov 23 '20 at 8:50
  • $\begingroup$ Scaling at that end is going to depart dramatically from the theoretical. $\endgroup$ – Russell Borogove Nov 23 '20 at 11:20
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In addition to Russel Borogove's answer there is also the XKCD design using modern model rocket motors and a complex staging profile that got an orbital vehicle that is 'an unstable pile of gunpowder the size of Central Park' and the British Interplanetary society black powder design that I cannot find numbers on beyond 5 stages and 'the mass of an ocean liner'. Most of the BIS design work was expended on the instrumentation and guidance of the lander rather than the launch vehicle.

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