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Very cool! For someone who knows absolutely nothing about rockets, this makes it look so much more primitive for some reason. Just these tubes filled with fuel.
by thatguyagain 6y ago
Very cool! For someone who knows absolutely nothing about rockets, this makes it look so much more primitive for some reason. Just these tubes filled with fuel.
- amelius 6y agoYes, we'll have to find a new phrase for "rocket science" :)
- munchbunny 6y agoThat's pretty much what rockets are: massive fuel tanks and a ton of hardware to keep the resulting explosion under control. The really hard part is keeping the explosion intentional and pointed where you want it to go.
- Ididntdothis 6y agoFundamentally the purpose of a rocket is to throw mass behind it very quickly. The idea is pretty simple but the implementation turns out to be quite complex.
- dotancohen 6y agoAs someone who knows quite a bit about rockets, they really are for the most part this primitive. Just these tubes filled with fuel, with a few volts of angry pixies at the top controlling a few degrees of gimbaling at the bottom.
- pjc50 6y agoAlmost all the engineering magic and weight is at the bottom: nozzles to handle very high temperatures, high-pressure high-speed turbopumps, and so on. The falling Falcon stages have the aerodynamic stabilisation of a shuttlecock, and their low center of gravity helps them be stable on fairly small legs.
- twicetwice 6y agoAs others have said, that's basically the case. Most of the complexity, though, is at the bottom, in the engines. Absolutely incredible machines designed to withstand—and control—incredible forces. Turbopumps spinning at tens of thousands of revolutions per second. Insane amounts of heat that need to be cooled so the engine bell doesn't melt. Handling cryogenic fuels (liquid oxygen is very, very cold!) at very high pressures, moving them at very high speeds. One failure mode, out of the many many possible failure modes, that's particularly interesting to me is that if the pressure in the pipes going into the turbopumps (which push the fuel into the combustion chamber fast enough to keep the explosion going) is too low, then you'll get cavitation on the back of the turbopump blades, and the forces from that will destroy the turbopump in under a second. Kaboom. Oh, also, these pumps have to spin so fast that they themselves are driven by essentially little mini rocket engines. For a visual depiction of the complexity of rocket engines, check out SpaceX's Raptor engine, arguably the most advanced engine being produced right now: https://imgix.bustle.com/uploads/image/2020/4/6/c1349369-162d-4430-a789-bad843d8d9ad-eu0suuexqaizgul.jpeg https://imgix.bustle.com/uploads/image/2020/4/6/c1349369-162... I'm no rocket scientist, though, just an interested amateur. Real rocket scientists please correct me if I got anything wrong!
- lutorm 6y agoTurbopumps spinning at tens of thousands of revolutions per second. This is actually not true. These turbopumps are quite large and spin fairly slowly. The design RPM on the F-1 turbopump appears to have been 5500 RPM, for example. (That's not to say they aren't complicated, because they were using 55,000 horsepower to push the propellants into the engine.)
- elteto 6y agoNot all of them! The Merlin turbopump spins at a whopping 36k RPM! [0] https://en.m.wikipedia.org/wiki/SpaceX_Merlin#Turbopump https://en.m.wikipedia.org/wiki/SpaceX_Merlin#Turbopump
- twicetwice 6y agoYup, that's what I was thinking of... I learned most of what I know about rockets from /r/SpaceX and related places! :)
- lutorm 6y ago36,000 RPM is 600 RPS, which is still aways off from "tens of thousands".
- twicetwice 6y agoOops, you're totally right, I messed that up. Too late to edit the parent unfortunately. I think it's certainly still impressive, though!