Okay... Here's the last three pics for this study...
First off we have the structural impacts of the "23(L)" vehicle, with the percentage of strengthening and additional dry weights incurred on each stage, plus the tank stretches necessary to optimize the performance, within the 410 foot height limit and the performance capabilities of the engines.
Second we have a chart showing the performance of the "23(L)" vehicle when used with no LRBs, a pair, or all four. Interestingly, a companion study found that costs were basically insensitive to the booster diameter, between 200 and 300 inches. I would have LOVED to see the cost estimates for a 396 inch booster, which was studied, but no data given. Basically, this would have been strapping a pair of S-IC stages to the side of the "23L" vehicle, instead of FOUR of the ALL NEW 260 inch boosters. Essentially, it would have been a "Delta IV Heavy" designed 30+ years earlier... with each 396 inch booster, essentially a downrated S-IC with FOUR F-1 engines, (which incidentally was the first stage configuration for the "INT-20" vehicle, which would have increased flight rates and reduced costs, while increasing payload performance MASSIVELY over Saturn IB!) these "boosters" could have been produced side-by-side with the S-IC stages used for first stages on Saturn V-- increasing the production numbers and gaining economies of scale, reducing per-unit costs. Also, the mass fraction of the boosters should have been better, since ONE 4-engine 396 inch "booster" should have been lighter than the TWO 2-engine boosters it replaced... it would have also reduced the amount of seperation hardware and pad mating hardware necessary, though certainly it would have required a new MLP, which many of these proposals did anyway... or simply due to the numbers and flight rates they assumed in the studies (which were rather unrealistic IMHO-- 30 flights in 5 years seems overly optimistic to me-- while the early pace of Saturn V flights WAS frenetic, after the first moon landing was successfully accomplished, the flight rate dropped to more like 2 per year until Apollo ended-- and with these larger and costlier rockets and payloads, the 2 per year figures seem much more 'affordable' and believable than 6 per year... flight rates REALLY have a HUGE effect on your program costs-- higher flight rates reduce per-unit costs by amortizing infrastructure and workforce overhead by spreading it out over a larger number of flights. IE, doubling flight rate essentially 'halves' your infrastructure costs since it's spread over twice as many flights... )
Sadly it appears that this idea didn't get beyond the initial trades on booster size, for whatever reason... but even if it meant having to add another line for S-IC boosters beside the new MS-IC upgraded cores (which would have had to been retooled for anyway) it would have been cheaper than creating an ENTIRELY NEW 260 inch booster assembly and checkout line, and it would have given you an 'optimized' "INT-20" vehicle first stage as a side-benefit (the mods necessary for the "INT-20" first stage, capping off the LOX ducts through the fuel tank bulkheads and capping off the engine connection ports on the fuel tank and LOX manifolds could have been "permanently changed" on the booster assembly line, and the unneeded hardware removed rather than simply 'corked off', reducing weight and costs. Course the flip side of that is, it would be easy to add that fifth engine back to the booster and have FIFTEEN F-1 engines available at liftoff... :y:
and in only TWO boosters-- THAT would have rattled a few windows at liftoff!! :kill::bangbang:
At any rate, it would have made some interesting trades, and some interesting models...
Last we have the conclusions page, which is a screencap directly from the study itself. Interesting reading, due to the tradeoffs and lead times and expenditures required to get the various rockets ready to fly... Really demonstrates how the choices would have been made... for instance, the "3B" vehicle, with NO boosters, which would seem "easiest" to build, actually had the greatest expenditure and lead time of any of the proposals, due to the fact that it used all-uprated engines in all the stages-- redesigned F-1's and all-new high-pressure bell or toroidal aerospike engines, which would have taken years and millions to develop (at the time). The "4(S)B" vehicle, on the other had, using "small" existing 120 inch SRMs, with existing off-the-shelf F-1 and J-2 engines already being used on Saturn V, requiring only tank stretches for extra propellant and generally stiffening up the stages, would have been one of the quickest and cheapest to create, despite the need for the MAHS and extra crawler, etc. The liquid boosted rocket (23(L)) would have had the most capacity, but would have had some pretty big infrastructure impacts at KSC... new crawler was anticipated and new MLP, mods to existing MLPs, etc... Lots of interesting tradeoffs, and depending on where you're priorities lie, the answers you get at the end are markedly different... Neat stuff...
That's it for this one! Enjoy and go build a Saturn V with SRBs!!!
oint: OL JR