On the other hand, I think a Saturn IB was more expensive than a Titan IIIC...
A lot of that cost was tied up in the S-IVB and in system-wide low production volumes--after all, they only built a total of about two dozen of them under conditions that were more focused on getting something in the size class flying than optimizing for production cost. There were extensive studies that pointed out ways to significantly reduce the production cost for both stages (though particularly the S-IVB) to reach costs which would have been much more competitive with Titan in volume production.
I really don't understand this obsession with Saturn IB as an alternative to STS. This idea crops up over and over again on this site (more frequently lately as more people accept that STS was a mistake and failure).
The bad points of the first stage already mentioned (high dry weight, high cost) are inherent in Saturn I's origin as a quick-fix temporary solution to three temporary problems:
Politically, S-IB was a non-starter because it was built by the Chrysler Corporation, which in those days was very healthy and not threatened with bankruptcy like the traditional aerospace firms. Those same aerospace firms were also determined to drive Chrysler out of the space business.
The result was a booster stage that not only looked obsolete by 1969, but actually was obsolete (by comparison with Titan III and Proton).
Quote from: Arch Admiral on 03/07/2018 08:52 pmThe result was a booster stage that not only looked obsolete by 1969, but actually was obsolete (by comparison with Titan III and Proton).... but of those 3 rockets, it was the only one using fuels safe enough to put human on top of the rocket.
1. The quick fix for these problems was to weld together a bunch of Redstone & Jupiter tanks, bolt on some slightly modified Thor/Jupiter engines, and connect them with a rat's nest of pipes and wires. There was no thought that Saturn I would become a permanent part of the space program, and so no thought was given to efficiency or cost-effectiveness. The result was a booster stage that not only looked obsolete by 1969, but actually was obsolete (by comparison with Titan III and Proton).2, Politically, S-IB was a non-starter because it was built by the Chrysler Corporation, which in those days was very healthy and not threatened with bankruptcy like the traditional aerospace firms. Those same aerospace firms were also determined to drive Chrysler out of the space business.
I think it virtually inevitable that the clustered 1st stage would have been replace with a 6.6m mono core booster...for those reasons you mentioned. Perhaps with an additional engine and upgraded engines. A mono core tank would be both more volume and mass efficient.
Quote from: Lobo on 03/08/2018 12:11 amI think it virtually inevitable that the clustered 1st stage would have been replace with a 6.6m mono core booster...for those reasons you mentioned. Perhaps with an additional engine and upgraded engines. A mono core tank would be both more volume and mass efficient.Why is it such a persistent belief that the S-IB's multi-tank structure was a major drag on the Saturn IB's performance? It wasn't. And that is now doubt why the expensive proposition of completely redesigning the first stage does not appear among the many proposals for increasing the rocket's performance (Saturn IB-A, -B, -C, & -D; Saturn INT-05, -05A, -11. -12, -13. -14 & -15).
Quote from: Proponent on 03/08/2018 10:38 pmWhy is it such a persistent belief that the S-IB's multi-tank structure was a major drag on the Saturn IB's performance? It wasn't. And that is now doubt why the expensive proposition of completely redesigning the first stage does not appear among the many proposals for increasing the rocket's performance (Saturn IB-A, -B, -C, & -D; Saturn INT-05, -05A, -11. -12, -13. -14 & -15).Well, it wasn't a huge drag per se, but it was more of a stop gap to get it together quickly using existing tooling used for Jupiter and Redstone tank production. Via the Saturn 1 stage, it was ready before any of the other Saturn V components. After they'd all been produced, then there was experience with larger tooling. But again, since there wasn't plans to produce the stage indefinately, it was ok to have the clustered design. But why wasn't the S-1D clustered with smaller tanks? And why have we never really seen a booster (or any stage) use it since? Well, it's just a sub optimal way to do it from mass, volume, and plumbing standpoints.
Why is it such a persistent belief that the S-IB's multi-tank structure was a major drag on the Saturn IB's performance? It wasn't. And that is now doubt why the expensive proposition of completely redesigning the first stage does not appear among the many proposals for increasing the rocket's performance (Saturn IB-A, -B, -C, & -D; Saturn INT-05, -05A, -11. -12, -13. -14 & -15).
So had the SAturn 1B been chosen instead of STS to be NASA's LV in the post-Apollo era, and Jupiter and Redstone rocket products was getting phased out (or already had been, not sure when that production of new tanks stopped exactly), and Douglas already had 6.6m tooling to build the S-IVB, I just don't see anyway that Saturn 1B wouldn't have gotten a new mono core.Or they would have had to restart the Jupiter and Redstone tank tooling to keep making the S-1B stage. Dunno, just seems unlikely they would have continued on with that for their LV of record for the next few decades. I could see them using any existing stages and tanks stocks, but probably looking at a different booster stage rather than restarting production of those tanks. So there were more production reasons for a new booster, than just the mass penalties of the clustered design.As for the various Saturn 1B INT concepts you mention, some replaced the S-1B with multiple Titan SRB's, or one single very big SRB. Others keep the S-1B and add Solids. So they seemingly were considering replacing the S-1B as it was. They were just thinking Solids rather than liquid.But you make a point, they didn't seem to be thinking liquid mono core. At least not when those concepts were looked at. But later in the 70's when this would have happened? Who knows?
Even though the evolution to a single tank type structure appears to make sense, I believe, in one of the other threads where we have been down this road, it would not really been much of an improvement over the S1B. It would have drive up costs too, because it would require an all new structure. An F-1 would not have had an engine out capability, which may or may not have been an important factor. And then, it would not be capable of a powered landing, so it is right out of consideration for this thread.
I must point out the Titan III engines, except for the transtage, were really not any different than Titan I or II engines. Those engines could run on LOX/Kerosene, LOX/Methane, LOX/Hydrogen, as well as hypergolics. Adding length to tankage was never, in the old days, much of a challenge.
Absolutely -- the clustered-tank design was sub-optimal from a pure performance perspective and was adopted during the post-Sputnik panic largely because of the desire to build something big quickly and cheaply. But that doesn't mean that eliminating the clustered tanks was a sensible use of money. It doesn't make sense that you'd develop a whole new stage just to add less than a tonne to the LEO payload, unless you'd already tried everything else and really, really needed the extra payload. NASA might conceivably have spent money on a new first stage with significantly better characteristics. But it would not have made sense to spend money on a new first stage for the Saturn IB that was just like the old one except for the clustered tanks: it would have failed the cost-benefit test.
Agreed, re: the first stage. The biggest bang for the buck would have been to change the second stage, rather then mussing with the S-IB stage. Shifting to a LOX/RP second stage powered by three Atlas sustainer engines, designed for Atlas sustainer type propellant mass fractions, could have reduced launch costs with minor loss of performance to LEO. A benefit would have been that the entire machine would have used, essentially, the same engines as NASA's Atlas-Centaur.But, as we've discussed, the first stage would had to have been substantially redesigned and re-engined to achieve Falcon 9 like recovery - and recovery would have bit hard into performance. - Ed Kyle
... the S-IVB did already exist, and worked and didn't really -need- changes
There was no thought that Saturn I would become a permanent part of the space program...
... no thought was given to efficiency or cost-effectiveness.