What if Apollo/Saturn Had never been Cancelled?

[Lobo]

Anyone know the price of an S-IC stage vs. the price of an S-IB stage?

And how much each F-1 engine cost on the S-IC stage?

[Downix]

Anyone know the price of an S-IC stage vs. the price of an S-IB stage?

And how much each F-1 engine cost on the S-IC stage?

I do have that written down somewhere, I'll dig it out.  IIRC, in 1969 each engine was about $6 million, and the S-IC was close to $40 million on top of that, but I'm not 100% sure on that.

[TomH]

O.K., here's the link. This gives an incredibly detailed history of the Apollo program from inception to finish, not just the technical stuff, but the politics as well. In it you will find information on the spending profile and "surge". The report is very well annotated with sources. It is fascinating reading.

http://www.munseys.com/diskone/chariot.htm

[jnc]

far too many were deceived into believing that a resuable vehicle would be an order of magnitude cheaper. We all know how that went.

Hindsight's 20/20. I don't think (although maybe my memory is playing tricks on me) that people really understood, in advance, how difficult the reusability would be, really.

'The difference between theory and practise is even bigger in practise than it is in theory', etc, etc.

Noel

[QuantumG]

O.K., here's the link. This gives an incredibly detailed history of the Apollo program from inception to finish, not just the technical stuff, but the politics as well. In it you will find information on the spending profile and "surge". The report is very well annotated with sources. It is fascinating reading.

http://www.munseys.com/diskone/chariot.htm

Thanks Tom. Chapter 6 somewhat covers my recollection of the "LOR Classic" prior to the Apollo hardware mandate.

http://www.munseys.com/diskone/chariot.htm#6

"All during the year, Chamberlin and his team had been working on a study of putting two men in space in an enlarged Mercury capsule (which later emerged as Project Gemini). Although this successor to Mercury had been conceived as earth-orbital and long-duration, Chamberlin thought it might fly to the moon, as well. Seamans recalled that Chamberlin “was trying to develop something that was almost competitive with the Apollo itself.” Chamberlin did, indeed, offer an alternative to Apollo. He and several of his colleagues proposed using the two-man craft and lunar rendezvous in conjunction with a one-man lunar lander, which in many respects resembled the small vehicles studied by Langley."

For people who like compromise, and I'm not one, Apollo is a great story of engineers giving in to political expediency.

[mike robel]

C3 started out as 2 F-1s. with a 10M diameter, and then went to 3 F-1s.  My Saturn 1F2 was 260 Inches.

No, it started at 6.6m, then grew to 8.4m before finally settling at 10m in its third iteration.  I would have left it at either 6.6m or 8.4m, the 10m being too wide for center of pressure purposes.  I have a good document on the C-3 as it originally stood, even a clustered first stage form of 4 for a lunar direct landing configuration capable of lifting over 140 metric tons, all around the 6.6m/260" design.

Now you have to realize, how in my modeling world, the Saturn 1F2 evolved.  I built the Saturn MLV 24 (L) with streched SIC and SII tanks and a NERVA 3rd Stage, as well as 4 260inch Liquid strap ons with 2 F-1s each.

While I was waiting for the LRB nose cones to arrive, it occured to me that an SIVB would sit fine upon the booster, so since the Saturn IB/V IU could handle boost, I said to my self, "Self, why not" and built it.  It looked pretty snazzy and more capable than the Saturn IF.

And that is how the 1F2 was born and inserted into this conversation.

and a good job too.

I stand corrected on the C-3 diameter.  My C-3 model is built at 27 feet diameter or 8.2 Meters.

Thanks for the compliment on the model.

[Downix]

C3 started out as 2 F-1s. with a 10M diameter, and then went to 3 F-1s.  My Saturn 1F2 was 260 Inches.

No, it started at 6.6m, then grew to 8.4m before finally settling at 10m in its third iteration.  I would have left it at either 6.6m or 8.4m, the 10m being too wide for center of pressure purposes.  I have a good document on the C-3 as it originally stood, even a clustered first stage form of 4 for a lunar direct landing configuration capable of lifting over 140 metric tons, all around the 6.6m/260" design.

Now you have to realize, how in my modeling world, the Saturn 1F2 evolved.  I built the Saturn MLV 24 (L) with streched SIC and SII tanks and a NERVA 3rd Stage, as well as 4 260inch Liquid strap ons with 2 F-1s each.

While I was waiting for the LRB nose cones to arrive, it occured to me that an SIVB would sit fine upon the booster, so since the Saturn IB/V IU could handle boost, I said to my self, "Self, why not" and built it.  It looked pretty snazzy and more capable than the Saturn IF.

And that is how the 1F2 was born and inserted into this conversation.

and a good job too.

I stand corrected on the C-3 diameter.  My C-3 model is built at 27 feet diameter or 8.2 Meters.

Thanks for the compliment on the model.

Is your model of the 28m tall, 34m tall or 36m tall form of C-3?

[edkyle99]

In a non-Shuttle alternative history, I'd guess that had any Saturns survived, they'd have been with minor modifications, namely upgrading the J-2 to the J-2S and the F-1 to the F-1A, and making opportunistic weight reductions.

My guess would be that in that alternative history, NASA would have been able to keep only one of the two Saturns.  Saturn IB maybe.  J-2S would likely have been adopted at some point, and NASA would have needed to create some type of upper stage or tug to bolt atop S-IVB.  The Agency could have run a long-term space station program with those "Proton-like" tools, though it really could have used an even smaller launch vehicle for crew/cargo.  A heavily upgraded Atlas Centaur could have, for example, matched Soyuz capability to LEO.

 - Ed Kyle

[Proponent]

However, that still doesn't address the issue of if NASA had basically -only- been offering Apollo Applications options to the post-Apollo NASA planning, instead of the red herring of a cheap reusable spaceplane?

Why even entertain options that would basically throw away all of this new hardware that so much money was spent on.  Since it's been said repeatedly that the axes hard started to fall before Apollo 11 had even landed (or earlier), it was certainly known or expected that funding would be lean after the peak.  No money for another bleeding edge program.  yet that's exactly what the Shuttle would be.  Even if they didn't realize just HOW expensive or HOW bleeding edge, they certainly new it would be another leap forward, but without the fat cold-war space race budget Apollo had.   Besides that, it would only be cost effective at very high flight rates, and they also had to know that the chances of haivng the funding for enough payloads to utilize it was slim to none.

We now know that the Shuttle never delivered on its promises, but I don't think it can be called a red herring.  As far as I can tell, NASA was enthusiastic about the Shuttle, and there were not many doubters (though there certainly were some -- like this board's very own dbaker -- and they should have been listened to).  I don't think Congress insisted on a Shuttle; it just insisted on a low budget.  Had I been in the loop, I'm sure I would have been an enthusiastic Shuttle supporter.  After all, suppose you were skeptical and believed the Shuttle would deliver only half the promised reduction in  dollars-per-pound to orbit and only half the promised flight rate.  It still would have been great investment.  With a budget that supports either Apollo Applications or the Shuttle but not both, I'd say it would  have been hard to make a case for Apollo Applications, given NASA's projections and its reputation at the time (how difficult could a better ride to orbit be for the agency that had just been to the moon?).

[Lobo]

Shuttle was sold as moving beyond exploration to the commercial exploitation of space. The vision, as it was sold, was that whole new constellations of military and commercial satellites would be launched cheaply by the shuttle. "Blacken the sky" and such. In retrospect, the launch of the TDRS satellites were all that was needed to sell the Shuttle.

The key phrase you had there is "as it was sold".

Which begs the questions, "why was it sold like that?"  "Who sold it?"  And "Why didn't they KNOW better?"  Who's at fault for the false bill of goods?
It wasn't demanded by Congress or the President, it was "sold" to them by someone else...

Yea, I know hindsight is 20/20  I get that they wouldn't have known -all- of the problems that woudl come along with the Shuttle.  But hey, these are the guys who put a friggin man on the moon!  They should have been able to come up with some realistic development and annual cost projects...even back then....

Also, back then, is there really any way they wouldn't have known that TDRS satellites could be launched just as well on ELV's?  The shuttle was in no way necessary to launch them?
So again, a false bill of goods....someone (or someones) who knew better are guilty of that...if they weren't "selling" it like that, and if they were "selling" Apollo Applications, what's the reason they couldn't have "sold" that just as well instead of STS?]

[Lobo]

In a non-Shuttle alternative history, I'd guess that had any Saturns survived, they'd have been with minor modifications, namely upgrading the J-2 to the J-2S and the F-1 to the F-1A, and making opportunistic weight reductions.

My guess would be that in that alternative history, NASA would have been able to keep only one of the two Saturns.  Saturn IB maybe.  J-2S would likely have been adopted at some point, and NASA would have needed to create some type of upper stage or tug to bolt atop S-IVB.  The Agency could have run a long-term space station program with those "Proton-like" tools, though it really could have used an even smaller launch vehicle for crew/cargo.  A heavily upgraded Atlas Centaur could have, for example, matched Soyuz capability to LEO.

 - Ed Kyle

I'm pretty sure they would have wanted to down select to just one, but I imagine the Saturn V could have survived.  I mean, they had funding for a brand new HLV with cutting edge reusable orbiter in the Post Apollo years, so I'm pretty sure they could have kept Saturn V very easily.  They would have been typically launching the INT configs, rathan than the full Saturn V.

But, if you think keeping the Saturn 1B would have served better in the post Apollo years, then there might have been a strong case to develop the S-1F to replace the S-1B.  Or I suppose you could have creatd the Saturn 1B "Heavy with 3 cores. 

The nice thing about the S-IVB stage is it already had an RCS system. So it actually could have put in place Space Station segments, and then deorbited itself.  It might have needed a bit of an upgrade to make it the most useful in that capacity, but that would have been a nice capability of it.  You really wouldn’t have needed the Apollo CSM to go up to in order to place payloads where precision was required, like in construction of a space station. 

The S-1F vs. the S-1B could have been a trade study.  The S-1F would offer advantages, like better volumetric efficiency of a mono tank vs. tank cluster.  And if used with an F-1, then the plumbing would be significantly cheaper/easier than the S-1B, which had 9 tanks and 8 engines.
However, the S-1B was already developed and flying.  And it could have gone through some evolutions to get a little better performance out of it.   In which case, the F-1 could have been retired, and the H-1 ramped up in production per the SpaceX model.  Smaller engines with a high production rate.  I’d heard that 8X H-1 engines were lighter and cheaper than 1XF-1?  Is that true does anyone know?
Maybe it could have gone through a latter evolution of a switch to an S-IVB derived monotank (two tanks rather than a common bulkhead probably though), if the Jupiter and Redstone tanks became unavailable (any one know when those rockets were finally retired and they weren’t making tanks for them any more?).  If those tanks were being built –only- for S-1B, then it sort of takes away part of it’s cost advantage.  So a new mono tank might have been a logical upgrade then.  It would have needed to have a load-bearing barrel too then rather than the cluster structure.  But again, that could be derived from the S-IVB.  The two stages really could be consolidated onto the same line.  Since the F-1 would have been retired, it could still fly with the H-1 engines. 
The Heavy version should get around 60mt to LEO.  Since the S-IVB was the more expensive stage, a Saturn 1B-Heavy wouldn’t be a whole lot more expensive than a Saturn 1B I wouldn’t think. 

[Lobo]

We now know that the Shuttle never delivered on its promises, but I don't think it can be called a red herring.  As far as I can tell, NASA was enthusiastic about the Shuttle, and there were not many doubters (though there certainly were some -- like this board's very own dbaker -- and they should have been listened to).  I don't think Congress insisted on a Shuttle; it just insisted on a low budget.  Had I been in the loop, I'm sure I would have been an enthusiastic Shuttle supporter.  After all, suppose you were skeptical and believed the Shuttle would deliver only half the promised reduction in  dollars-per-pound to orbit and only half the promised flight rate.  It still would have been great investment.  With a budget that supports either Apollo Applications or the Shuttle but not both, I'd say it would  have been hard to make a case for Apollo Applications, given NASA's projections and its reputation at the time (how difficult could a better ride to orbit be for the agency that had just been to the moon?).

Well, I suppose I mean red herring in hind sight.  But even then, like I said, these were the brains that put a man on the moon.  They should have known better.
I understand the attraction of the next greatest thing.  So I understand how having an “airplane” flying to space would have seemed pretty exciting.

But, these are the best minds on the planet, not a kid wanting a new toy for Christmas.  Mercury, Gemini, and Apollo were all projects that started without existing capability to do the objective.  Mercury started with nothing, and wanted to put a man in space.  So they had to develop that capsule from scratch.  Redstone and Atlas existed, so they were used as an LV.  Gemini was to do something in space, not just get there.  Mercury was no capable of that, so Gemini was built.  Titan already existed, so it was used as an LV.  Then we wanted to go to the Moon.  There was no rocket big enough, so a new one needed to be built.  There was no capsule or lander that could do it, so those had to be built new as well.  (although the Gemini capsule actually might have been able to do direct ascent, but there would be no way it could do EOR or LOR as there was no way to transfer the crew to a lander other than an EVA.  So it really wasn’t a good choice once EOR or LOR was chosen over Direct Ascent. ).   
So in each case, we actually did use existing hardware where it existed, and built new where it didn’t to achieve the goal.
After Apollo, what was the goal?  Originally I think it was to put up a space station and live and work in LEO for a prolong time, and to reduce costs to get there.  A reusable space plane was one way to do that, and after it was selected, I think the Space station was scrapped because the Shuttle could put a crew in space for a few weeks and there probably wasn’t enough money for a space station with the Shuttle’s enormous development costs.
However, if the goal was to put a space station up, and live and work in space, and to reduce costs, the difference was existing hardware –did- exist, and could do the job quite well, as we proved with Skylab.  The Shuttle was a way to do it, but not the only way, and not necessarily even the best way.  With a space station, you don’t need that huge space ship that takes a Saturn V class LV to get into LEO.  All you need is a small taxi like Saturn 1B and Apollo. 
The airliner/truck concept –seems- like a good idea, but again, these are the beset minds in the world.  They should have understood space flight is not air flight nor ground transit.  When you aren’t overcoming gravity, you don’t need a “truck”.  All you need is an RCS system.  You aren’t fighting gravity in orbit.  You don’t need to “lift” a payload out of a “truck bed”.  You don’t need to “roll out” a payload from a cargo airplane’s cargo deck.  All you need to do is jettison the PLF, and have a way to maneuver it into position. 
Hindsight or not, these uber-brain all –must- have understood this back then.  There were two options to achieve the goals of a space station and cheaper space flight.  Utilizing the existing technology and hardware which was –still- bleeding edge tech only developed and built a few years prior, or scrapping all of that and going with a brand new capitol project, with even more bleeding edge tech, that ultimately will only do what your existing hardware will do.  Hindsight or no, what capabilities did they think STS gave them over Apollo Applications, other than downmass?
Even if they really thought at a high enough flight rate the Shuttle would be economical, they had to know there would never be a budget to get that flight rate where it needed to be…even if they thought the Shuttle could be turned around and reprocessed that cheaply/quickly. 

And finally, even if all of these uber-brains missed all of the obvious rules of economics of engineering that even this humble applications engineer with no experience in Aerospace can see, the fact they didn’t even use the existing hardware for the Shuttle booster was borderline nuts.  I know, lots of politics and all of that.  And the Saturn V components were looked at.  But that they chose to develop a brand new HLV for the Shuttle (and yes, I understand that the shuttle is part of the LV) when they could have used their existing INT-21, just boggles the mine.  So not only did they want a shuttle, seems like they really wanted to make it’s development as expensive as possible. 
A Buran-like Orbiter with payload could have sat just fine on top of an INT-21, and been no taller than the full Saturn V stack (including Apollo LAS tower), it could have used existing Saturn V Mobile Launchers (with a modified crew access tunnel for the different crew hatch location), so the ML towers wouldn’t have had to be relocated and fixed to the pads.  A clean pad system could have been kept.  The pads and ML’s were already set up to fuel the S-IC and S-II, and the flame ports and trench were already set up for the the S-IC, so minimal changes there.  There probably would have had to be a major modification to the MSS, or a new one built specifically to cover the Shuttle payload bay like the RSS did, but that would be less than the remodeling of both pads and all 3 ML’s which was needed for STS. 
If my math is correct, the fully fueled S-IVB massed 115mt, the Apollo CSM was 30mt, and the LEM was 25mt.  So by taking all of that off the S-IC/S-II stack, that’s 170mt fully fueled, or 65mt with a dry S-IVB during rollout.  So a 70mt Shuttle with a 20mt payload should have been only about 25mt more at rollout than the full Saturn V stack.  So I’ll assume the existing CT could have handled that?  And once on the pad, then the INT-21/Shuttle stack would have been around 80mt less than the fully fuelled Saturn V stack.
There could have been upgrade paths for a reusable S-IC stage which could parachute down like the SRB’s did, and be refurbished down the road, if having that reusability was that important to them. I believe part of the reason for SRB’s was that they’d be recovered and “reusable”.  But that could have been an upgrade later after the Shuttle was flying. 
That would have saved the development of the SRB’s, of the 8.4 ET, and of the SSME’s. 

I know there was a Shuttle concept which side mounted it on the S-II stage and basically used that as the “ET”, with five J2 engines on the Shuttle.  But that has it’s own problems.  A new S-II stage development for one.  Probably J2 upgrades to make them reusable (I am assuming they weren’t designed for reuse?) And a pretty significant off-center load while the stack is sitting on the ML.  Probably an entirely new ML tower design to support that overhung mass 42m above the base of the ML.  So it’s hard to say if keeping those five J2 engine would be worth all of that extra difficulty.  I’d guess not.  Better to upgrade to the more simple and cheap J2S and just mass produce them to get costs down.  Then the S-II stage wouldn’t have to be changed like that, nor the tower or ML.
The S-IC stage could probably be converted from 5 F-1’s to 4 F-1A’s, which would trim some more cost.

Seems if that “red herring” attraction of  a reusable space plane was that great, then that would have been the obvious booster choice.  And it would keep the components for a BLEO LV in production if/when a BLEO mission was funded.
I’m not sure what you do with S-IVB or Apollo CSM.  Development of the orbiter would probably suck up all available funds so they might want to trim anything not directly related to that.  So I’m not sure if S-IVB or Apollo CSM would survive that.  Ideally they would, so we’d retain our BLEO capabilities, but I sort of doubt it.  However, if a BLEO mission was green lighted down the road, only a new 3rd stage and a new capsule would need to be developed.  You’d already have your 1st and 2nd stages ready to go.  Would have been a much easier thing than going from STS to CxP or SLS. 

Interestingly enough, INT-20 with 4XF-1 engines could get 60mt to LEO.  If they could have gotten away with a smaller shuttle, maybe 45mt with around a 15mt payload, then it could have launched on an INT-20. 

[Proponent]

Well, I suppose I mean red herring in hind sight.  But even then, like I said, these were the brains that put a man on the moon.  They should have known better.
I understand the attraction of the next greatest thing.  So I understand how having an “airplane” flying to space would have seemed pretty exciting.

I suspect one problem was that a reusable spaceplane had been part space cadets' thinking for so long that it was hard for the engineers to analyze it dispassionately.  Von Braun's associate Konrad Dannenberg mentioned this in a mid-1990s interview available on the UAH website (log in as "guest" with password "anonymous").

In retrospect I can see some other problems that a good non-technical manager might have been able to foresee.  First of all, the Shuttle was a vehicle of an entirely new kind; was it really plausible that pretty much the first one off the assembly line would be an operational vehicle, without an experimental or prototype version being built first?

Secondly, NASA had shown that, given a blank check, it could build amazing technology, but it had never shown much of an ability to manage programs to cost.  The Shuttle was all about economics; was NASA really capable of that?

I suspect these questions didn't get asked enough because Apollo's success had bred overconfidence within NASA and overawe outside of it.

[Lobo]

Well, I suppose I mean red herring in hind sight.  But even then, like I said, these were the brains that put a man on the moon.  They should have known better.
I understand the attraction of the next greatest thing.  So I understand how having an “airplane” flying to space would have seemed pretty exciting.

I suspect one problem was that a reusable spaceplane had been part space cadets' thinking for so long that it was hard for the engineers to analyze it dispassionately.  Von Braun's associate Konrad Dannenberg mentioned this in a mid-1990s interview available on the UAH website (log in as "guest" with password "anonymous").

In retrospect I can see some other problems that a good non-technical manager might have been able to foresee.  First of all, the Shuttle was a vehicle of an entirely new kind; was it really plausible that pretty much the first one off the assembly line would be an operational vehicle, without an experimental or prototype version being built first?

Secondly, NASA had shown that, given a blank check, it could build amazing technology, but it had never shown much of an ability to manage programs to cost.  The Shuttle was all about economics; was NASA really capable of that?

I suspect these questions didn't get asked enough because Apollo's success had bred overconfidence within NASA and overawe outside of it.

As unfortunate it is in hindsight, I think your analysis is spot-on.  Heck, I'd have probably be luered to a shiney new space plane too.
And yea, NASA was probably riding on the Apollo high and feeling pretty invincible.  People probaby -did- know better, but there was also probably a mentality that if they could put a man on the moon, they could make a reusable space plane program easy and affordable...even if the little voices in their heads warned of issues with that.  Those same voices in their heads probably warned them that they weren't ready to put men on the moon, and they did that... so....

I still don't get how they didn't just insist on using the Saturn V component to make the Shuttle's booster though.  that seems like just a no brainer.  Even if they wanted a reusable space plane, it had to have a booster to get it into orbit.  They had a booster that could have gotten it into orbit.  INT-20 or INT-21, depending on how big they wanted to make the orbiter. 
even if they cancelled for good the Apollo and Saturn components that wouldn't directly support the Shuttle, like the CSM and S-1B stage, using INT-20 or INT-21 would have meant they only needed one development program, and no new engines, boosters, or new tank diameter.  And almost all of your exisitng launch facilities could have been used with only minor modifications.
I'm sure the anticipated reusability of the SRB's played a part in going that direction, but it seems like it should have been pretty apparent those SRB would be getting a good LONG soak in the ocean, and thus need a fair amount of refurb work.  Not to mention having to go all the way back to Utah to be refueled.  And the major ML and pad mods to accomodate those heavy boosters.  Seems like that long list of "cons" would have very clearly outweighed any "pros". 
And even if they wanted to eventually get to a system that had maximum reusibility, seems they could have started with expendible boosters, then once the orbiter was flying and operational, then a next phase could have been developed of a more reusable booster.  Parachute recovery of the S-IC, or possibly flyback LRB's strapped onto the S-II stage instead of the S-IC stage, etc.

Just seems that even if the leuer of a space plane was too much to resist for an invincible NASA, They should have been a little more realistic on the booster at least the Block 1 model.  Keeping INT-20 or INT-21 would have also kept us with a HLV that could have lofted very large and heavy payloads into LEO, like major space station components.

[Proponent]

The S-1F vs. the S-1B could have been a trade study.  The S-1F would offer advantages, like better volumetric efficiency of a mono tank vs. tank cluster.  And if used with an F-1, then the plumbing would be significantly cheaper/easier than the S-1B, which had 9 tanks and 8 engines.
However, the S-1B was already developed and flying.  And it could have gone through some evolutions to get a little better performance out of it.   In which case, the F-1 could have been retired, and the H-1 ramped up in production per the SpaceX model.  Smaller engines with a high production rate.  I’d heard that 8X H-1 engines were lighter and cheaper than 1XF-1?  Is that true does anyone know?

As for the relative weights of the engines, it wouldn't be too tough for you to look that up, no?   And if you do, you could compare the thrust-to-weight ratios of the H-1 against that of the F-1A, which had a sea-level thrust of 1.8 Mlb and was probably just a bit lighter than the F-1.

As for cost, no doubt one factor would be the production rate of the F-1(A).  Since each IB used eight H-1s and essentially the H-1 was shared with the Delta, I have a pretty strong suspicion that eight H-1s would have been cheaper at any plausible flight rate.  The increased thrust of the F-1A, though, would allow the Saturn IB to be stretched, increasing it's payload capacity, if there were a good reason to do that.

Maybe it could have gone through a latter evolution of a switch to an S-IVB derived monotank (two tanks rather than a common bulkhead probably though), if the Jupiter and Redstone tanks became unavailable (any one know when those rockets were finally retired and they weren’t making tanks for them any more?).  If those tanks were being built –only- for S-1B, then it sort of takes away part of it’s cost advantage.  So a new mono tank might have been a logical upgrade then.  It would have needed to have a load-bearing barrel too then rather than the cluster structure.  But again, that could be derived from the S-IVB.  The two stages really could be consolidated onto the same line.

Everybody seems obsessed with the S-IB's multi-tank structure.  It certainly wasn't optimal, but I'm have a hard time seeing how completely redesigning the stage would have been cost-effective.  As I showed previously in this thread, the payload benefit of switching to a mono-tank S-IB would have been small.  With the S-IB stage being cheaper than the S-IVB anyway, modest cost reductions of the S-IB wouldn't have had a big impact on vehicle costs anyway.  Documents I've posted previously in this thread put the cost of the multi-tank stage about even with that of the S-IVB, assuming a substantial production rate of S-IVBs for both Saturn IBs and for Saturn Vs.  In a scenario with just a few Saturn IBs and no Saturn Vs produced every year, the S-IVB surely would have been quite a bit more expensive than the S-IB.

<snip>

The Heavy version should get around 60mt to LEO.  Since the S-IVB was the more expensive stage, a Saturn 1B-Heavy wouldn’t be a whole lot more expensive than a Saturn 1B I wouldn’t think.

Maybe a triple-core Saturn IB would have required sufficient redesign of the first stage as to make going to a mono-tank design sensible.  Anyway, without cross-feed I get 43,700 kg to a 100-nautical-mile orbit due east from KSC for a three-core Saturn IB with a J-2S upper stage and SA-217 weight reductions.  I removed four engines from the core S-IB to keep the thrust-to-weight ratio down to about where it was for the plain vanilla Saturn IB (doing so also increases the payload, by making the vehicle more like a three-stager).  With cross-feed, the payload rises slightly to 45,100 kg (I'm wondering why the difference is so small).  For comparison, the payload of the triple-core Saturn IB is in between the payloads with two or 4 UA-1207 SRMs strapped on (about 37,000 kg and 48,000 kg, respectively).

Just for the fun of it, I attach a 1970 paper presented by Jack Swigert that briefly compares Shuttle- and Saturn-IB-boosted space-station programs.

P.S.  Streamlining the S-IB so that it has the same structural efficiency as the Atlas V (dry mass is 7.4% of propellant mass) boosts the payload capability of the triple-core Saturn IB with cross feed to 47,200 kg.

[Lars_J]

Ironically the Saturn 1F2, as proposed here, would have been an ideal liquid booster for STS.

[Proponent]

I still don't get how they didn't just insist on using the Saturn V component to make the Shuttle's booster though.  that seems like just a no brainer.  Even if they wanted a reusable space plane, it had to have a booster to get it into orbit.  They had a booster that could have gotten it into orbit.  INT-20 or INT-21, depending on how big they wanted to make the orbiter.

Granted, the INT-21 (though not the INT-20) could have orbited an entire Shuttle Orbiter.  But what would have been the point of orbiting such a huge spaceplane on a large expendable launch vehicle?  The expendable launch would mean giving up even the pretense of drastically reducing the cost of getting a pound to orbit.  The Shuttle Orbiter served as a payload carrier, but if had been boosted to orbit by an INT-21, there would have been little gained by putting the payload inside the Orbiter; the payload could simply have ridden on the INT-21 itself.  The only reason I can think of for such a large Orbiter would be if there were great demand for return of large loads from orbit, and that seems unlikely to justify the cost of an INT-21 for each flight.

In other words, what I'm saying is that if you're going to use an expendable launch vehicle, the orbiter might as well be a small, crew-only craft.  Such a vehicle requires a Saturn-IB-class launch vehicle, not one of the INT-21-class.

[spacenut]

I've see a proposal somewhere where the Saturn V first stage was to have upgraded F-1 engines at 2.2 million lbs thrust each, delivering 11 million total.  The flame trenches were originally built for this at the pads.  Also, the first stage was to have a heat shield attached at top of the stage.  It was to parachute down after boost, shield side down with engines out of the water and towed back to the VAB.  The J-2 engines were to be upgraded to 250,000 lbs thrust each also.  This would have increased the LEO payload to about 150 tons.  The 3rd stage was also to have a heat shield to come back through the atmosphere and land.  One version had pop out landing legs for ground recovery.  Another had a plug nozzle engine based on the J-2 installed on the 3rd stage.  It could have been a single stage to orbit or a reusable 3rd stage.  I haven't seen anything proposed on the 2nd stage. 

The whole reason I think was for a Mars assembly launcher or a 10 meter diameter space station. 

Lots of incremental improvements could have been made to the Saturn V to increase it's payload over time. 

[Lobo]

I still don't get how they didn't just insist on using the Saturn V component to make the Shuttle's booster though.  that seems like just a no brainer.  Even if they wanted a reusable space plane, it had to have a booster to get it into orbit.  They had a booster that could have gotten it into orbit.  INT-20 or INT-21, depending on how big they wanted to make the orbiter.

Granted, the INT-21 (though not the INT-20) could have orbited an entire Shuttle Orbiter.  But what would have been the point of orbiting such a huge spaceplane on a large expendable launch vehicle?  The expendable launch would mean giving up even the pretense of drastically reducing the cost of getting a pound to orbit.  The Shuttle Orbiter served as a payload carrier, but if had been boosted to orbit by an INT-21, there would have been little gained by putting the payload inside the Orbiter; the payload could simply have ridden on the INT-21 itself.  The only reason I can think of for such a large Orbiter would be if there were great demand for return of large loads from orbit, and that seems unlikely to justify the cost of an INT-21 for each flight.

In other words, what I'm saying is that if you're going to use an expendable launch vehicle, the orbiter might as well be a small, crew-only craft.  Such a vehicle requires a Saturn-IB-class launch vehicle, not one of the INT-21-class.

I agree completely, which is my whole argument for keeping Saturn and not having gone with STS.
And if the Orbiter would have ridden uphill on some large booster that took it most of the way and then came down and landed like an airplane or something (as was one of the early concepts), and the Shuttle had an internal upper stage to get it to orbit, or some cheap expendable upper stage to push it to orbit, then I could see.  But what they cam up with was a system no better than sticking the Shuttle on top of INT-21 and launching it!  That’s my point.  They spent billions to develop something that did basically what INT-21 would have done.  Except INT-21 would have had not development costs, and minimal pad and ML upgrade costs.
The ET is basically a new rocket with no MPS.  The SRB’s take a long soak in the ocean, and then need to be carted back to Utah in sections.  That stack required major pad and ML modifications.  Basically, they –did- stick the orbiter on a big expendable stack. 

An INT-21 launched shuttle could have mounted the IU and all the avionics in the Shuttle so those would be reused as they were with STS.  A “Block 2” S-IC could have been made reusable or semi-reusable, but that development cost could have been put off until the orbiter was flying.

I’m just saying, they could have started out by using their existing hardware with plans to evolve it into a partially reusable system, if they wanted to present a partially reusable launche system.   As it was, they developed a partially reusable system at the same time as the Shuttle itself, and incurred all of that development cost all at once.  And in the end, the cost of SSME development and then refurbishment, the ET development and new build every launch, and the SRB development and then refurbishment, really wouldn’t have been any cheaper or easier than INT-21. 

Anyway, I’m sure I’m repeating myself by this point.  ;-)  And I totally get your points, and they are good ones.  Seems like using INT-21 as the booster because it existed and didn’t need to be developed would be an easy call, but I’m sure I’m looking at that with the 20/20 hindsight glasses.  Might not have been so clear back then.  And if it did become clear, it might have been too far along in the process, and the Saturn production lines too long shut down to make going back to that any more feasible than forging ahead.

[Archibald]

if you're going to use an expendable launch vehicle, the orbiter might as well be a small, crew-only craft.  Such a vehicle requires a Saturn-IB-class launch vehicle, not one of the INT-21-class.

Excellent reasonning there. Mind you, that was the conclusion reached by NASA deputy administrator George Low (May 1971), and Nixon PSAC shuttle subcommittee member Eugene Fubini (October 1971).

That crew only shuttle with limited payload was called "the glider" (since it had no SSMEs).

In fact Fubini did such a good job promoting the glider that the OMB endorsed it on October 22, 1971. In turn, the OMB tried to impose it to NASA.
It was Matematica that understood the danger and, on October 28, presented NASA with the shuttle that was actually build - the familiar vehicle we all know.

Yet Matematica and NASA had to battle Nixon PSAC and OMB until January 3, 1972; before that date, the shuttle was nothing more than the glider. It was only two days before Nixon formal announcement that James Fletcher and George Low were sure they would have the full size, Matematica orbiter.