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Hello! I am between jobs right now and I bought a new computer that can run KSP before my last job ended. I can't afford to buy KSP itself right now, though I will treat myself to it when I get my next job. In the meantime I am a big alternate history fan, and also a fan of space technology and history, and plan to use KSP to model proposed possible alternate history configurations. One interest of mine is whether it might have been possible to repurpose developed Space Transport System technology to make a family of useful launch vehicles with relatively cheap and quick development time, rather than what has been done historically--which was to simply reuse the existing Shuttle fleet until it was deemed superannuated, and then enter an era where the USA had no crewed flight launch ability whatsoever. Over time since the last Shuttle flight, SpaceX in particular and also some competitors in New Space have developed pretty good new launchers and spacecraft and realistically I think these will be America's ticket back into crewed missions in Low Earth Orbit and beyond. However as an alternate history fan I would like to demonstrate some other possibilities we missed out on. My question seems to be an odd one, as I cannot seem to find any online source that details the answer. Bottom line is I want to know, of the three type of dry segments of the historic Shuttle Solid Rocket booster, what were their separate dry masses? My reasons for wanting to know this might require some involved answers but the short version is, I want to be able to estimate how varying the Boosters by -shortening- rather than lengthening them, by removing segments, so we could have three smaller variants with 3, 2 or conceivably even just one segment of solid propellant, to use for smaller expendable or semi-expendable launch systems that would be literally Shuttle Derived in design would have worked out. What I do know is that overall, the historic SRBs each massed 589 metric tonnes fully loaded with propellant, and that propellant massed 502 tonnes, so the six segments--one nose segment, one nozzle segment, and 4 propellant units--massed about 88 tonnes at burnout. It would shed some mass descending but I am only interested in the mass at burnout, not the mass recovered. If all segments were identical in dry mass that would imply each one was 14.3 tonnes, but of course I think the nose and nozzle units each massed more. If we were to make smaller booster units with fewer segments, the nozzle section would have to be redesigned for each possible size, since the mass flow of exhaust gasses is determined by the number of segments. The throat and nozzle would scale down to keep the same expansion ratio, and this means it is lighter and thus easier to move so the gimbaling hydraulic system and its actuators would be smaller in proportion too; conservatively I would guess it scales with 2/3 power of the number of segments, or by area, though it might work out to be closer to linear. So I want to know if anyone already knows for a fact the dry mass of any two of these three elements since then I could compute the third one. That would tell me the burnout mass ratio of a smaller system (or larger though I am not really interested in that). Since the solid fuel segments have little job to do but be strong cylinders that can contain the peak pressure of the grain combustion I suspect they massed remarkably little, say 8 tonnes each, which gives just 32 for the 4 of them and thus the nozzle and nose sections between them would total 56 tonnes, of which about under 2/3 I guess would be the nozzle, for say a 40 tonne nozzle unit (!) and 16 tonne nose unit. If we don't try to recover the boosters but just let them splash, I suppose the nose unit can be lightened more. Well 40 tonnes for the nozzle strikes me as pretty absurdly high, so I hope these aren't close to true figures. But that's my best guess for now. Anyone able to set me straight? I can't just look at SLS's boosters because they aren't really "Shuttle Derived" in that the grains have also been modified, in addition to adding another fuel section. They don't compare directly. I want to know what the classic Shuttle booster mass breakdown was, so I can see what the ratios would be for proper literally Shuttle Derived variants.