What if Apollo/Saturn Had never been Cancelled?

[Proponent]

I occurs to me to wonder whether, when McDonnell Douglas decided to bid on the EELV program, any engineer there might have considered putting an RL-10-powered upper stage on top of a 3- or 4-meter-diameter first stage powered by five or six RS-27s.  It would simultaneously have been an enlarged Delta II, thus truly earning the name "Delta IV," and smaller Saturn I, say about a Saturn 0.7.  The RS-27 cluster would surely have been less efficient and probably more expensive than the RD-180 used on the rival Atlases III and V, but they would have been American-made and the first stage itself, minus engines, would have been smaller and cheaper than the actual Delta IV's bulky hydrogen-fueled first stage.

[Downix]

I occurs to me to wonder whether, when McDonnell Douglas decided to bid on the EELV program, any engineer there might have considered putting an RL-10-powered upper stage on top of a 3- or 4-meter-diameter first stage powered by five or six RS-27s.  It would simultaneously have been an enlarged Delta II, thus truly earning the name "Delta IV," and smaller Saturn I, say about a Saturn 0.7.  The RS-27 cluster would surely have been less efficient and probably more expensive than the RD-180 used on the rival Atlases III and V, but they would have been American-made and the first stage itself, minus engines, would have been smaller and cheaper than the actual Delta IV's bulky hydrogen-fueled first stage.

McDonnell Douglass did bid on the EELV program, and won.  We call it the Delta IV.  The RS-27 proposed design was an engine for the Atlas family, not the Delta, but it lost out to the RD-180. An upgraded version of the MA-5A, with each chamber upgraded to 1,890 kN, giving the launch vehicle a total of 5,670 kN at lift-off, dropping two of the engines part-way through launch as was done on previous Atlas designs.  An EELV Heavy using such an engine design would be almost exactly half of the total thrust of the Saturn V.

[RanulfC]

And Skylab itself probably could have been extended if STS hadn’t been in the works and sucking up all the budget, and the S-1B or S-1F  and S-IVB stages, as well as new Apollo CM’s would still be in production and available for more crews and resupply missions.

Uhm, need to keep in mind that Skylab was pretty much EOL (End-of-Operational-Lifetime) by the last flight unless you're "assuming" a total re-design it wasn't actually possible to keep it operational.

For one thing the damage done, despite the repairs was a limiting factor, probably more importantly though it was designed with a limited life-time in the first place. (The "garbage-can" LOX tank was nearly full on the last fight and there was no way to extend the equipment lifetime with the way it was built)

Any "Skylab-2" design would probably have opened up the LOX tank and/or installed a larger air-lock and second docking adpater to that section for expansion and upgrade purposes.

As for the whole "wet-lab" idea I know it's been talked about for a long time but the real limiting factor is the needed on-orbit astronaut work-load for the concept. Its just so labor intensive that it doesn't seem "feasable" with current suit technology, and there is/was little incentive to change that towards a more workable design.

Randy

[Jim]

I occurs to me to wonder whether, when McDonnell Douglas decided to bid on the EELV program, any engineer there might have considered putting an RL-10-powered upper stage on top of a 3- or 4-meter-diameter first stage powered by five or six RS-27s.

They proposed this way before the EELV program.

[RocketmanUS]

And Skylab itself probably could have been extended if STS hadn’t been in the works and sucking up all the budget, and the S-1B or S-1F  and S-IVB stages, as well as new Apollo CM’s would still be in production and available for more crews and resupply missions.

Uhm, need to keep in mind that Skylab was pretty much EOL (End-of-Operational-Lifetime) by the last flight unless you're "assuming" a total re-design it wasn't actually possible to keep it operational.

For one thing the damage done, despite the repairs was a limiting factor, probably more importantly though it was designed with a limited life-time in the first place. (The "garbage-can" LOX tank was nearly full on the last fight and there was no way to extend the equipment lifetime with the way it was built)

Any "Skylab-2" design would probably have opened up the LOX tank and/or installed a larger air-lock and second docking adpater to that section for expansion and upgrade purposes.

As for the whole "wet-lab" idea I know it's been talked about for a long time but the real limiting factor is the needed on-orbit astronaut work-load for the concept. Its just so labor intensive that it doesn't seem "feasable" with current suit technology, and there is/was little incentive to change that towards a more workable design.

Randy

They were looking to fly the shuttle in 1979 to save and use Skylab. Shuttle as we know did not fly until 1981.

They could have launched Skylab 5 to save it and use it for added missions.

A new station might have used Skylabs size and some of the tooling to make the new modules. With the 1975 Apollo-Soyuz test project we might have seen Russian docking ports on the new modules. If so our history could have had a different path than it did outside of space flight.

If we kept our heavy lift in place there might have been also a joint Lunar base ( lower cost for both teams ). Followed by a Mars trip. We might have still seen Mir, along with orbital transfer vehicles between stations and free floaters.

What was the yearly overhead for Saturn V even with no flights back in 1970ish dollars? Same for Saturn 1B?

If we would have had added flights in the 70's how might that have had an impact on the economy? Would the Fed seen a greater return on that investment in those years over the shuttle investment?

[RanulfC]

They were looking to fly the shuttle in 1979 to save and use Skylab. Shuttle as we know did not fly until 1981.

From what I could gather it was never actually a "serious" proposal at least not considered such at NASA anyway.

They could have launched Skylab 5 to save it and use it for added missions.

It would not have managed to actually 'save' much as the station itself was not designed for extended use. Which was THE real problem right there. Even if they had managed to save it from de-orbiting, (and they could have used a number of expendable boosters and automated docking to attach the needed re-boost equipment IF they had actually wished to) it didn't change the situation on station life. There was no way to clean out the LOX tank and not much in the way of refurbishing or re-supplying for needed upgrades and repairs.

Skylab just was not designed for extended use and with the additional damage done initially it wasn't seen as an "asset" for future missions. It just could not be made to handle those additional duties.

A new station might have used Skylabs size and some of the tooling to make the new modules. With the 1975 Apollo-Soyuz test project we might have seen Russian docking ports on the new modules. If so our history could have had a different path than it did outside of space flight.

Oh I'm sure it would have, (I've read the Alternate History thread on this "path" and enjoyed it FYI ) the problem is the IDEA was for the "Shuttle" to deploy and support an even bigger and "better" space station than any "puny" Skylabs

If we kept our heavy lift in place there might have been also a joint Lunar base ( lower cost for both teams ). Followed by a Mars trip. We might have still seen Mir, along with orbital transfer vehicles between stations and free floaters.

By 1975 our relations with the USSR were on the wane again and any thoughts of "long-term" cooperation were going to be side-lined by politics in the following years so while it's a "nice" idea, (lest we forget, recall that Kennedy thought of it also ) it just was not going to happen.

I think the major problem with "keeping" our Heavy-Lift capability with the Saturn and Apollo vehicles was two-fold. A reusable, frequent flying shuttle in support of and along with a LEO space station was seen as "the" next thing in space by a majority of folks who had control over and influance with the decision making process which pretty much doomed the Saturn-V early on. Had it not been for the "rush" to get the Lunar Landing done in under 10 years it's probable that a lot more time and effort would have gone into EOR and on-orbit assembly which probably would have negated the very reasoning FOR the Saturn-V itself.

More importantly though the political and economic support for the space program was failing and as far as I can tell the "option" for continuing Saturn/Apollo was not even on the table. I'm sure it could have been 'argued' for had anyone seen the need but the overall consensus AT THE TIME was that the "right" way to do space was a step-by-step progression from one point to another and THE 'next' step was a LEO space station and supporting shuttle craft. So I suspect absent a VERY large change in attitude somewhere high up in NASA the continuation of Saturn/Apollo was just not going to happen.

Which I think was a pity because DESPITE the short-comings of the Saturn-1/1B overall it was a DAMN fine start on an evolution towards a large reusable booster system. (The H-1s despite their performance were DAMN robust engines and they had been "proven" in every way short of actual flight-testing to be reusable despite the worst they would see with in-flight and recovery operations. Had they been paired with a similarly robust booster vehicle....)

What was the yearly overhead for Saturn V even with no flights back in 1970ish dollars? Same for Saturn 1B?

If we would have had added flights in the 70's how might that have had an impact on the economy? Would the Fed seen a greater return on that investment in those years over the shuttle investment?

Oh the Shuttle was SHOWN to be MUCH cheaper to design and operate, just look at all your "historic" data available!

Of course that was part of the problem in that we didn't actually have a CLUE as to how difficult doing the shuttle was going to be. Nor of course did anyone at that time understand how the political and financial realities were going to impact exactly what the shuttle was and how it was going to be designed.

Unfortunatly the overall "tone" of how NASA was to operate and view itself was set by the Apollo-Moon-Landing program and once that mind-set and world-view was "set" as an operating paradigm dealing with fiscal and political reality became very, very difficult.

When given a choice of either a Space Shuttle OR a Space Station the choice was "obvious" because once you HAD the Shuttle you could build the Space Station and resume the step-by-step process of building up a space-faring infrastructure. Or so the theory goes at any rate...

The problem was that wasn't how NASA was "used" to operating and the Shuttle became a "program" rather than JUST a launch vehicle as it was supposed to be. Given that any "Space Station" would also have to be a "program" (and it was) and so on. So instead of a step-by-step process where you build up infrastructure and capability for the next step along the way, it becomes a political and financial "fight" to gain and secure support and funding for each new "project" more often than not at the expense of the previous "project" at some point and time.

We could have regained our "heavy-lift" capability using components of the Shuttle stack to create a new heavy lift vehicle. But that was seen as "competition" to the Shuttle itself, taking away "reasons" for political and financial support.

We could have (and should have) gone through a series of upgrades and improvements over the years on the whole Shuttle system. Not JUST the incrimental stuff that was done but serious upgrades including a new orbiter and other "improvements" to the overall system. But again, this would have taken away support both financial and political from the "Shuttle" (note if you haven't already the fact that it IS the "S"huttle rather than just a "s"huttle) and would have adversly effected continued operations.

And now that's gone too, with little left to "carry-on" in the next system. But that's the way the "system" works since we don't have an overall "program" that is being worked towards, each and every "system" becomes the "reason" by and of itself in a circular pattern.

And despite a lot of rhetoric about "goals" and "visions" the reality is that the "system" is justified by goals and visions rather than goals and visions defining the "systems" as it should be. The system is geared to defining "program" where a "system" is designed, built and supported with specific "missions" in mind but no overall goal or vision beyond getting the "system" built and into operation.

Apollo/Saturn had ONE specific "goal" and once that was accomplished it no longer had a justification or reason for being. Similarly the Shuttle had only one "goal" and that was to exist and operate. Nothing more, as everything else became secondary to that specific goal. My suspicion is that the SLS is going to be the same way, focused simply on existing and operating until it too is discarded but I may be being cynical

I don't think NASA can operate any other way. I'm quite sure that that the poltics currently won't allow any such change and I'm not sure that such a sweeping change is even possible given the circumstances and history of how NASA was born and raised. But I could be wrong....

Randy

[Lobo]

It would not have managed to actually 'save' much as the station itself was not designed for extended use. Which was THE real problem right there. Even if they had managed to save it from de-orbiting, (and they could have used a number of expendable boosters and automated docking to attach the needed re-boost equipment IF they had actually wished to) it didn't change the situation on station life. There was no way to clean out the LOX tank and not much in the way of refurbishing or re-supplying for needed upgrades and repairs.

Skylab just was not designed for extended use and with the additional damage done initially it wasn't seen as an "asset" for future missions. It just could not be made to handle those additional duties.

I agree with this.  In my little pretend alternate history, I am assuming Skylab would have happened just like it did.  An application use of leftover hardware from Apollo 18-20.  It was our first stab at a space station, so nothing wrong with using leftovers as a test bed.  And nothing wrong with letting it be just what it was.  If we’d downsized Saturn in the post-Apollo era, and just baselined on the Apollo CM, a LEO SM, and the Saturn 1B, with perhaps a Saturn 1B-Heavy variant, then Skylab would have been probably the last heavy Saturn launch.  The S-IC and S-II would have never continued production like the S-IB and S-IVB. 
The important information learned from Skylab could have went into the next station design.  Especially the lessons of needing to be able to get rid of garbage (rather than stuffing it into the LOX tank), the needs for reboost, the needs to service external parts of the station, and the needs for future expansion.  Basically, I think Space Station Freedom was such a station, utilizing lessons learned from Skylab, but designed to be constructed by the Shuttle.  If we didn’t have the Shuttle, but had Saturn 1B and Saturn 1B-Heavy, then we could have designed larger modules to be launched on Saturn 1B-Heavy (or smaller ones launched on Saturn 1B, but I think it would be advantageous to go larger modules with less in orbit construction, especially as we didn’t have the Shuttle).  And set in place by the S-IVB stage which has it’s own RCS system and could put payloads directly into the necessary orbit (it maybe have requires a few upgrades to make it a good “tug” though).  If Saturn IB-Heavy put a 45mt-ish base module up, with hub connections, a shuttle-like robotic arm, ECLSS system, airlock, etc, that could support a crew of 3 for a period of time.  Then they could be there when the next Saturn 1B-Heavy brought the next module up.  And they could have used the robotic arm and even to EVA’s to assist in mating the new module.  And so on.  Since the S-IVB could act as a tug, each module wouldn’t have needed it’s own RCS system like I believe the Mir modules had.  If you put four 45-50mt modules up there, all mated to a central “dumb” structural hub, then you’d have a pretty sizable next station, and each module could be removed and deorbited and replaced when/if necessary.  Saturn 1B with Apollo CSM could do crew rotations, and Saturn 1B with a MPLM could bring a large amount of supplies to the station, and then act as a garbage can the way Progress, HTV and ATV are with the ISS.  If a reboost was needed, it could either be done by Apollo SM (depending on how the LEO version was build, if they included SMME and enough propellant to do it.), or even perhaps the S-IVB could do it.  Launch a Saturn 1B with mating adaptor rather than the payload on the S-IVB, dock it with the station, and let it do  the reboost.  The concern there might be that the J2S would have too much thrust to do that.  So it might be better to just design the LEO Apollo SM to have a smaller SMME and enough propellant that it could give the station a small reboost every crew rotation, as the SMME wouldn’t need needed to fire otherwise as the S-IVB would put it right on target with the space station.  The Apollo CM was about 6mt, so if you could have modified the existing SM, or built a new smaller one, that was around 12mt with a smaller SMME and fuel, that could launch with the LAS tower on Saturn 1B and perform a reboost each crew rotation. 

I think the major problem with "keeping" our Heavy-Lift capability with the Saturn and Apollo vehicles was two-fold. A reusable, frequent flying shuttle in support of and along with a LEO space station was seen as "the" next thing in space by a majority of folks who had control over and influance with the decision making process which pretty much doomed the Saturn-V early on. Had it not been for the "rush" to get the Lunar Landing done in under 10 years it's probable that a lot more time and effort would have gone into EOR and on-orbit assembly which probably would have negated the very reasoning FOR the Saturn-V itself.

More importantly though the political and economic support for the space program was failing and as far as I can tell the "option" for continuing Saturn/Apollo was not even on the table. I'm sure it could have been 'argued' for had anyone seen the need but the overall consensus AT THE TIME was that the "right" way to do space was a step-by-step progression from one point to another and THE 'next' step was a LEO space station and supporting shuttle craft. So I suspect absent a VERY large change in attitude somewhere high up in NASA the continuation of Saturn/Apollo was just not going to happen.

The point of this thread is that the option to keep Saturn V hardware and shelve the idea of a Shuttle was there, and that there was enough foresight to see the oncoming problems with the Shuttle, and to have not gone that route.  Obviously the conditions at the time were such that the Shuttle –was- chosen, and Saturn/Apollo hardware –was- cancelled.  Although, I still maintain that some of the brains at NASA should have known better, and should have known that they wouldn’t get Space Race level funding ever again, and that throwing away all of that high dollar and high tech development and starting over on something that was even more bleeding edge, just wouldn’t be fiscally sound.  Even if many at NASA felt invincible after Apollo and thought they could do anything for any price.  These geniuses should have known better.  And never even put the concept of the shuttle out there for politicians to be attracted to.  If NASA had just kept a unified front that a reusable space plane and the brand new LV needed to launch it, which would have no Saturn heritage, would just be too expensive given projected NASA budgets Post-Apollo.  And that they recommend utilizing as much of that great Saturn/Apollo development and hardware as possible for the next program.  Evolving it into reusable systems as feasible (reusable S-1B, reusable Apollo CM, etc) 
I think that path –could- have been taken, that these brains –should- have known better, even given the post-Apollo euphoria, and this thread just explores that.

Oh the Shuttle was SHOWN to be MUCH cheaper to design and operate, just look at all your "historic" data available!

Of course that was part of the problem in that we didn't actually have a CLUE as to how difficult doing the shuttle was going to be. Nor of course did anyone at that time understand how the political and financial realities were going to impact exactly what the shuttle was and how it was going to be designed.

Again, I’m sure there were very optimistic proposals.  But just a little common sense should have shown these big brains that something was very fishy with that.  They all knew how expensive a bleeding edge program like Apollo was. And that they’d have nowhere NEAR that funding or political support.  STS was the next level bleeding edge after Apollo, and they weren’t going to get any benefit of the money sunk into Apollo.  I’m just a simple applications engineer in the pneumatics industry, and if I was sitting in on a similar meeting, I’d be sure as heck raising my hand and pointing out the obvious.  That’s just engineering economics 101, space industry or not.

We could have regained our "heavy-lift" capability using components of the Shuttle stack to create a new heavy lift vehicle. But that was seen as "competition" to the Shuttle itself, taking away "reasons" for political and financial support.

Yes, this would have been much better than the Shuttle only.  It would have been good to have done this up front, to have designed STS to launch with or without the Shuttle, like Buran.  So it wouldn’t have been seen as competition later on.  There were concepts to do just that, and have a Jupiter-130 like HLV right from the get go, but with STS running so expensive, I imagine they never had the extra money for it. 

As discussed earlier in this thread, I think even if NASA and Congress was fixated on a reusable space plane, they could have used INT-21 to launch it, and save themselves a TON of development costs in developing the ET, SRB’s, and all of the extensive pad and mobile launcher modifications.  They could have put in an upgrade path for a reusable S-IC (as was an Apollo Applications concept already), and could have had a modified S-II stage that would have been an “ET” basically, with five J2S engines on the Shuttle instead of the 3 brand newly developed RS-25’s.  North American could have developed this variant for a fraction of what the ET cost to develop I imagine.   (I maintain that it would have been cheaper in the long run to launch a Buran-like Shuttle on top of the INT-21, and not had engines on it, and just mass produce the J2S and standard S-II, and over time that would have made those cheaper than trying to reuse five J2S engines….but, if people had to have more reusability, side-mounting Shuttle on the S-II and having the J2S engines on the Shuttle would have been a way)  And they could have retained their original S-II with thrust structure and mounted engines for launching INT-21 as a heavy lift stack.  S-IVB could have been retired as we weren’t going back to BLEO for a decade or more.  Then INT-21 could have been used to launch large modules for a permanent space station, and the Shuttle could have been used to service that space station.  Upmass, downmass, crew rotation, and all of the other things they wanted a Shuttle for. 

So, now you have your thought of the Shuttle stack, with a HLV derived from the Shuttle stack, but you have it without any of the development costs of the shuttle stack.  Just Shuttle development only.  I mean yea, now you are launching a HLV every time you want to put the Shuttle up, but we have been anyway with the STS stack, so that wouldn’t change any.  And I think the S-IC/F-1A could have been made to be as refurbishable/reusable as the SRB’s were.  And over time the S-IC and S-II are streamlined with more mass savings, more efficiency, and more automation as we get through the 80’s.  And, if there were money for a new BLEO program say in the late 80’s or something.  All we need is a new Apollo CSM, and a new EDS to put on top of the INT-21 stack, which would be much cheaper than having to develop all of that, plus a new stand along HLV, which is what we have to do now.  So we probably wouldn’t have been stuck in LEO for 30 years.

[RocketmanUS]

Skylab extension to me should have only been done with three added flight of Apollo for up to 30 days each till 1977. Flights to experiment with in space assemble and other things needed for the new station. And possible add propulsion to the station for deorbit. So only for a short use. They had enough water and oxygen for the added missions.


If NASA had gone with the smaller Shuttle for crew ( around 7 ) and some cargo ( maybe up to 10klb ) instead of the Shuttle we got with Air Force then we might of had a cost effective replacement for LEO over Apollo CSM. Taking small steps over time to experiment on heat shield for such a shuttle and other problem areas. Then fund the Shuttle to first flight if it still looked like it would have save money over the CSM. Sized for a Saturn 1B or a 70klb lifter. It should have been more commercial based.

Space Shuttle would have needed Shuttle Z with both using engines with less cost than what we had. Say an engine that could have been used 5 time and if only used once would have been cost effective. Cost per engine around $25M.

So even if they had kept Saturn they were looking into reusing the 1st stage of the Saturn V. It would have needed to later be upgraded to reusable engines too. That a an INT-20 might have been a better option with the smaller Shuttle.

As far as Russia with a new station back then we don't know. If We had gone with what I posted above then we might of had a different President and or Congress. lots of things might have changed because of a possible joint use space station. No matter what America needed it's own version of Progress.

Shuttle cost over other. Why did they ever believe it would be cheaper? The fact is they did not care as long as It looked like they were doing something good for the public ( Congressmen wanted votes ).

So what would a INT-20 with four F-1A's and a J-2S be able to bring to LEO over the F-1 and J-2? How much lighter back in the 70's could they have made the 1st stage? With a lighter 1st stage what mass would they have been able to get to LEO? Could they have gotten enough increase to send just the CSM to LLO and back?

Edit:
If we had used Saturn to launch a shuttle then we only had to spend money on a top mount shuttle over a side mount. We then could have latter improved or replace the Saturn as the launcher for such a shuttle as needed or cancel the shuttle if it were to cost to much.

[RanulfC]

The point of this thread is that the option to keep Saturn V hardware and shelve the idea of a Shuttle was there, and that there was enough foresight to see the oncoming problems with the Shuttle, and to have not gone that route.

Oh I understand the "point" of the thread and even agree with it somewhat I just think an "understanding" of the POV of the participants is somewhat helpful

While I'm pretty sure there was a lot of "foresight" on building a bleeding edge vehicle from pretty much scratch was around inside and outside NASA at the time I still stand by my point: The numbers were there, the data could be seen and understood but the "attitude" was such that any "retreat" into using the Saturn/Apollo systems was seen as an admission that "space" just wasn't going to ever be the priority it was again.

Hence the "shuttle" system turns into the "Shuttle" program...

Obviously the conditions at the time were such that the Shuttle –was- chosen, and Saturn/Apollo hardware –was- cancelled.  Although, I still maintain that some of the brains at NASA should have known better, and should have known that they wouldn’t get Space Race level funding ever again, and that throwing away all of that high dollar and high tech development and starting over on something that was even more bleeding edge, just wouldn’t be fiscally sound.  Even if many at NASA felt invincible after Apollo and thought they could do anything for any price.  These geniuses should have known better.  And never even put the concept of the shuttle out there for politicians to be attracted to.  If NASA had just kept a unified front that a reusable space plane and the brand new LV needed to launch it, which would have no Saturn heritage, would just be too expensive given projected NASA budgets Post-Apollo.

Until Von Braun "caved" NASA couldn't even present a "united-front" on how we were going to reach the Moon! EOR was the last 'vestige' of the original "space-program" around and when LOR was choosen it pretty much put paid to a "sensible" space development program in favor of "waste-anything-but-time" mission programing.

Part of the overall issue that has to be taken in context is that at the time the "Shuttle" wasn't the "Shuttle" but only a "shuttle" for construction and support of a LEO "Space Station" which in and of itself was only part of a larger and CONTINUING space program.

Large LEO space stations, continued Lunar landings, a manned Lunar base and eventual missions to Mars and beyond were ALL presented to the administration and fully backed by everyone at NASA as the "follow-on" to Apollo. Heck the Presidents OWN VP and "blue-ribbon" panel recommended it ALL to be funded, so it wasn't even just NASA having those rose-colored glasses. But when the choices were finally laid on the table in front of NASA there was A choice: Either a Space Shuttle OR a Space Station as the follow on, and even those would have restricted funding.

I suspect that if Von Braun had stuck to his guns and insisted on EOR but with the prevision that it would NOT be tied to "direct" lunar landing (landing the whole S-IVB stack on the lunar surface really) concept. That's probably when it would have been possible to "save" the Saturn/Apollo system from being eventually canceled. Anytime after that you're locked into the Saturn-V and LOR mission, but before that the choice was seen as being between direct or orbital rendevous schemes.

And that they recommend utilizing as much of that great Saturn/Apollo development and hardware as possible for the next program.  Evolving it into reusable systems as feasible (reusable S-1B, reusable Apollo CM, etc) 
I think that path –could- have been taken, that these brains –should- have known better, even given the post-Apollo euphoria, and this thread just explores that.

Yep got that
But I don't think it was ever really an either/or decision between Shuttle and Saturn/Apollo. I think the "decsion" point was earlier than that as I noted above and I DO actually think that IF that route had been taken we would not have even developed the Saturn-V. I'm just not so sure that doing so would have gotten us to the Moon by the deadline and that seems to have been the main thinking at the time also.

Again, I’m sure there were very optimistic proposals.  But just a little common sense should have shown these big brains that something was very fishy with that.  They all knew how expensive a bleeding edge program like Apollo was. And that they’d have nowhere NEAR that funding or political support.  STS was the next level bleeding edge after Apollo, and they weren’t going to get any benefit of the money sunk into Apollo.  I’m just a simple applications engineer in the pneumatics industry, and if I was sitting in on a similar meeting, I’d be sure as heck raising my hand and pointing out the obvious.  That’s just engineering economics 101, space industry or not.

The problem is I can't actually find anything that shows that kind of thinking WAS going on at the time

Part of it was the reasoning behind how NASA did the Moon program and part of it was the "culture" of, well, of "space" at the time. NASA HAD to get to the Moon by 1970 and that was that so they did and that colored the thinking. But at the same time everyone "knew" how space was supposed to be done and that was step-by-step in logical, self supporting stages that started with a reusable "shuttle" vehicle. (Not the "STS note)

But if you can step back and look at the "logic" of the situation it's pretty clear that a "reusable" space vehicle is a pretty major step in and of itself let alone NOT using any already developed and paid for technology. Yet there is a certain arrogance and willfulness that is pretty obvious once you look for it in the "space" minded folks of that time and despite being "rocket scientists" people are people and not immune from believing their personal bias' are "obvious" truths.

The biggest most powerful rocket engine in the world used LOX/RP-1 and was an amazing feat of engineering but it was seen as being to "low-tech" and "inefficent" for a REAL rocket. Nothing could hold a candle to LOX/LH2 as it was the most powerful chemical propellant that was available and everyone KNEW that once you had LOX/LH2 rockets that the performance would be enough to REALLY open up space travel. This wasn't a "belief" either, it was a "known" fact and anyone who suggested a reusable rocket shuttle should use anything else simply didn't understand basic chemistry!
(And the sad part is that's pretty much paraphrasing a Von Braun statement!)

And this "attitude" was pretty endemic all through the "space" brains big-and-small at the time. So this colored the thinking about the whole Saturn/Apollo system. While it had it's "high" points it was simply a "get-the-job-done-then-move-on" system rather than something to base the NEXT system on, or worse yet "burden" yourself with when it was "common-sense" that the NEXT system would be even better!

I see this kind of attitude and bias all through the writing and thinking of the time period and its pretty much why I take anything presented as "truth" in such statements with a HUGE grain of salt

As discussed earlier in this thread, I think even if NASA and Congress was fixated on a reusable space plane, they could have used INT-21 to launch it, and save themselves a TON of development costs in developing the ET, SRB’s, and all of the extensive pad and mobile launcher modifications.  They could have put in an upgrade path for a reusable S-IC (as was an Apollo Applications concept already), and could have had a modified S-II stage that would have been an “ET” basically, with five J2S engines on the Shuttle instead of the 3 brand newly developed RS-25’s.  North American could have developed this variant for a fraction of what the ET cost to develop I imagine.   (I maintain that it would have been cheaper in the long run to launch a Buran-like Shuttle on top of the INT-21, and not had engines on it, and just mass produce the J2S and standard S-II, and over time that would have made those cheaper than trying to reuse five J2S engines….but, if people had to have more reusability, side-mounting Shuttle on the S-II and having the J2S engines on the Shuttle would have been a way)  And they could have retained their original S-II with thrust structure and mounted engines for launching INT-21 as a heavy lift stack.  S-IVB could have been retired as we weren’t going back to BLEO for a decade or more.  Then INT-21 could have been used to launch large modules for a permanent space station, and the Shuttle could have been used to service that space station.  Upmass, downmass, crew rotation, and all of the other things they wanted a Shuttle for.

Which if I may say so is quite logical and sound thinking... And utterly UNTHINKABLE by the best "minds" of the time because of that very reasoning

They didn't think "Shuttle" after all they thought of it as "shuttle" and even then it was only a small part of a larger and more diverse program. Unfortunatly when it came time to "do" that very thing it had gone from "shuttle" to "Shuttle" and it WAS the "program" and there was no political or financial benift with re-using "old" technology. In fact there was incentive AGAINST such an idea because it was more politically supportable to "spread" the development around and spend money on changing and refurbishing the "old" infrastructure for the "new" program.

Unfortunatly.
 

So, now you have your thought of the Shuttle stack, with a HLV derived from the Shuttle stack, but you have it without any of the development costs of the shuttle stack.  Just Shuttle development only.

But that would have been "shuttle" development, not "Shuttle" development

Not that I don't agree with you

I mean yea, now you are launching a HLV every time you want to put the Shuttle up, but we have been anyway with the STS stack, so that wouldn’t change any.  And I think the S-IC/F-1A could have been made to be as refurbishable/reusable as the SRB’s were.  And over time the S-IC and S-II are streamlined with more mass savings, more efficiency, and more automation as we get through the 80’s.  And, if there were money for a new BLEO program say in the late 80’s or something.  All we need is a new Apollo CSM, and a new EDS to put on top of the INT-21 stack, which would be much cheaper than having to develop all of that, plus a new stand along HLV, which is what we have to do now.

Again, I don't and won't fault the logic and clear thinking behind this

I will however point out it simply wasn't "common" sense at the time.

So we probably wouldn’t have been stuck in LEO for 30 years.

THIS I have 'issues' with as despite any changes in the way NASA worked for the past 30+ years being "stuck" was much more a political than technology problem. We shouldn't forget this was also the time period of Proxmire and the "Golden Fleece" awards among other anti-technology and specifically anti-expanded NASA programs attitudes.

(Among others at the time one Rep. Rohrabacher was QUITE vehment about NO NASA Lunar or Mars plans or projects )

That attitude is still pretty prevelent in Washington especially among the Congress critters who control NASA budget and spending so my "hopes" of a near-term solution to this issue are a bit dim.

Randy

[RanulfC]

Skylab extension to me should have only been done with three added flight of Apollo for up to 30 days each till 1977. Flights to experiment with in space assemble and other things needed for the new station. And possible add propulsion to the station for deorbit. So only for a short use. They had enough water and oxygen for the added missions.

Possibly though by that time it was pretty "clear" that on-orbit assembly and work was going to be difficult at best. The "Shuttle" suits were supposed to greatly help with that issue but instead ended up being worse.

Even so any follow-on station had been pushed back due to lack of political support and funding cuts so I doubt any "interest" could have been generated at that time. I'm "assuming" of course that such an overall attitude would have been similar in an "alternate" time line of course.

If NASA had gone with the smaller Shuttle for crew ( around 7 ) and some cargo ( maybe up to 10klb ) instead of the Shuttle we got with Air Force then we might of had a cost effective replacement for LEO over Apollo CSM.

While I'd agree that a smaller, less expansive (and expensive) "general purpose" shuttle would probably have been better, again, by that time it had morphed into the "Shuttle" and was seen the "goal" of the "program" instead of simply a step. At that point nothing short of the "Shuttle" we got was going to be enough to justify the costs.

Taking small steps over time to experiment on heat shield for such a shuttle and other problem areas. Then fund the Shuttle to first flight if it still looked like it would have save money over the CSM. Sized for a Saturn 1B or a 70klb lifter. It should have been more commercial based.

Logical of course and clear but not politically supportable given the difference in "programs" that the CSM and Shuttle represented. One was simply a vehicle to get the "job" done, the other WAS the "job" to be done and "program" in and of itself.

Politically this is why we could never get a serious "upgrade" to the Shuttle. It would have been "admitting" that it wasn't perfect and fine as it was. Concepts for "Shuttle-II" kept smashing into the same political "reef" over the years. Why do you need to "improve" on what you have when you spent so much on getting it in the first place?

An unfortunate "trend" in aerospace over the decades really. We keep getting better and better equipment that we can't afford to actually buy

So even if they had kept Saturn they were looking into reusing the 1st stage of the Saturn V. It would have needed to later be upgraded to reusable engines too. That a an INT-20 might have been a better option with the smaller Shuttle.

I think the Saturn-V was "history" the day Apollo-11 landed no matter what path was followed. There were a lot of ideas on ways and means to recover and re-use the S-1C stage but it was really, really going to be difficult at best. And there was such a huge capability gap between the Saturn-1B and the Saturn-V I don't see how they could have justified keeping Saturn-V production going without a continuous Lunar program going. And that in and of itself was going to be almost impossible to defend. They may have continued with a Saturn-1 with F-1 engine(s) vehicle but the F-1 had a LONG way to go to get to the point of being as robust as the H-1 was already.

The 4-engine INT-20 was probably possible but I'd be surprised if that would have "flown" (pardon the pun) in that fiscal environment. And as I noted in my response to Lobo the "thinking" just wasn't there for that kind of program. Still you're correct that it would have both leveraged already existant ability and equipment and allowed for incremental upgrading of the system as finances and politics allowed.

Shuttle cost over other. Why did they ever believe it would be cheaper? The fact is they did not care as long as It looked like they were doing something good for the public ( Congressmen wanted votes ).

This hasn't changed I'll point out

"Looks" over "substance" is still the way Congess tends to operate if they can at all get "away" with it

So what would a INT-20 with four F-1A's and a J-2S be able to bring to LEO over the F-1 and J-2? How much lighter back in the 70's could they have made the 1st stage? With a lighter 1st stage what mass would they have been able to get to LEO? Could they have gotten enough increase to send just the CSM to LLO and back?

Well we're getting back into politics rather than technology but it was probably possible. I'd imagine that it would have been possible to "prove" out on-orbit propellant transfer with this set up an think what possibities THAT would have opened up

Edit:
If we had used Saturn to launch a shuttle then we only had to spend money on a top mount shuttle over a side mount. We then could have latter improved or replace the Saturn as the launcher for such a shuttle as needed or cancel the shuttle if it were to cost to much.

Well that's the whole point I was making about "shuttle" versus "Shuttle" in the first place

But you need to keep in mind that even if we had "recovered" and reused the S-1C stage in some manner it wouldn't be considered really "reusable" in the thinking of the day until they stuck wings on it and landing gear and brought it back for a landing at Kennedy. So imagine trying to get THAT as an "upgrade" program over the last 30 years.

You have a "perfectly" working system already, why are you coming before Congress (read that as "Lords-and-Masters" for the proper attitude ) and asking for "billions" to change a working system into something it's not? And what are you going to use it for anyway? Don't forget your arguing AGAINST cheese-subsidies here... 

Randy

[mike robel]

I think if the shuttle had not been developed, we would have retreated to LEO anyway.  Whether the Saturn IB would have survived, much less any other versions of Saturn hardware is doubtful.

Probably we would not have continued going to the moon.

A plausible course of action would have seen Saturn Is flown to expenditure and manned flight would have moved to the Titan IIIC which could have put Apollo Capsules into orbit, albeit shortfueled or better yet, with a smaller SM.

As an adjunct, Saturn Vs could have been also flown to expenditure, orbiting a new Skylab designed for long term continiuous operation and expandability.  There were two V's left over after all post Skylan, and they could have put up a sizeable station.

The ironic thing to me is that Titan III/IV could have orbited current ISS sized modules that were carried by the shuttle.  These could have been configured in such a way as to require minimum orbital assembly - just dock them.

Perhaps in this world, Dyna-Soar could have been resurrected or morphed into a reusable vehicle launched by Titan and, in a flight of fancy, the Titan Boosters made recoverable, though I doubt that would have been a cost saving, but may have been good public relations...

With 4 high bays in the VIB and two pads, USAF and NASA payloads could have flown without much interfering with each other.

We then could have flown a very Russion-like program in which Apollo and Titan III were continuously upgraded as was the Soyuz booster and spacecraft.

Perhaps then we would also have perfected the ability to use EOR to return to the moon.

Just one man's opinion.

[RocketmanUS]

Lets say they did go with INT-20 , INT-21 , and the new three core Skylab like space station ( with or without Russia ). ( no shuttle )

With that lift capacity ( mass and volume ) per flight we would not need that many flights per year. 3 for crew rotation ( INT-20 three F-1 engine model ) and 3 for supplies ( INT type based on mass and volume ) to the station.

The largest INT-21 could have launched four shuttle ( or Titan IV ) payloads to LEO for LEO, GTO, or BEO. Each with their own US.

They then could have made a larger capsule to land in S. Cal. desert for reuse ( crew or cargo ), cargo return. Land on land or water as a backup.

From another thread they could have used a hypergolic EDS ( or other space storable propellant ). BEO capsule/crew or cargo at station, depart when ready, no weather problems for launch window and have a greater mass to BEO compared to a single launch. This could have lead to great Lunar missions and flexible. Added advantages for fuel storage as we know is to have satellites launch to station and then with a space tug sent to it's needed orbit. For BEO probes launch it with an empty ( or almost empty ) EDS , fuel it at the station and launch when the window opens up ( no weather problem for launch window ), greater mass or faster traveling probe(s).

Hubble repair and upgrades would have been easier with a orbital transfer vehicle with EVA.

The advantages were to great and the risk to throw it away for the unknown was even greater, as we all know.

 

[RocketmanUS]

I think if the shuttle had not been developed, we would have retreated to LEO anyway.  Whether the Saturn IB would have survived, much less any other versions of Saturn hardware is doubtful.

Probably we would not have continued going to the moon.

A plausible course of action would have seen Saturn Is flown to expenditure and manned flight would have moved to the Titan IIIC which could have put Apollo Capsules into orbit, albeit shortfueled or better yet, with a smaller SM.

As an adjunct, Saturn Vs could have been also flown to expenditure, orbiting a new Skylab designed for long term continiuous operation and expandability.  There were two V's left over after all post Skylan, and they could have put up a sizeable station.

The ironic thing to me is that Titan III/IV could have orbited current ISS sized modules that were carried by the shuttle.  These could have been configured in such a way as to require minimum orbital assembly - just dock them.

Perhaps in this world, Dyna-Soar could have been resurrected or morphed into a reusable vehicle launched by Titan and, in a flight of fancy, the Titan Boosters made recoverable, though I doubt that would have been a cost saving, but may have been good public relations...

With 4 high bays in the VIB and two pads, USAF and NASA payloads could have flown without much interfering with each other.

We then could have flown a very Russion-like program in which Apollo and Titan III were continuously upgraded as was the Soyuz booster and spacecraft.

Perhaps then we would also have perfected the ability to use EOR to return to the moon.

Just one man's opinion.

Titan used solids, smaller volume payloads, less mass to orbit compared to INT-20 and INT-21 ( INT-21 up to 255klb to LEO ).

http://www.astronautix.com/data/satvint.pdf
Am I reading page 15 ( PDF counter , page 7 on bottom of page ) right that a three engine INT-20 cost $60M to launch back in the later 60's.

So what did A Titan IIIC cost? To compare.

[Downix]

I think if the shuttle had not been developed, we would have retreated to LEO anyway.  Whether the Saturn IB would have survived, much less any other versions of Saturn hardware is doubtful.

Probably we would not have continued going to the moon.

A plausible course of action would have seen Saturn Is flown to expenditure and manned flight would have moved to the Titan IIIC which could have put Apollo Capsules into orbit, albeit shortfueled or better yet, with a smaller SM.

As an adjunct, Saturn Vs could have been also flown to expenditure, orbiting a new Skylab designed for long term continiuous operation and expandability.  There were two V's left over after all post Skylan, and they could have put up a sizeable station.

The ironic thing to me is that Titan III/IV could have orbited current ISS sized modules that were carried by the shuttle.  These could have been configured in such a way as to require minimum orbital assembly - just dock them.

Perhaps in this world, Dyna-Soar could have been resurrected or morphed into a reusable vehicle launched by Titan and, in a flight of fancy, the Titan Boosters made recoverable, though I doubt that would have been a cost saving, but may have been good public relations...

With 4 high bays in the VIB and two pads, USAF and NASA payloads could have flown without much interfering with each other.

We then could have flown a very Russion-like program in which Apollo and Titan III were continuously upgraded as was the Soyuz booster and spacecraft.

Perhaps then we would also have perfected the ability to use EOR to return to the moon.

Just one man's opinion.

Titan used solids, smaller volume payloads, less mass to orbit compared to INT-20 and INT-21 ( INT-21 up to 255klb to LEO ).

http://www.astronautix.com/data/satvint.pdf
Am I reading page 15 ( PDF counter , page 7 on bottom of page ) right that a three engine INT-20 cost $60M to launch back in the later 60's.

So what did A Titan IIIC cost? To compare.

$72 million in 1969 according to the documents I have.

The CR INT-20 would have had its cost reduced to $55 million, thanks to the reduced costs of the F-1A and J-2S along with other cost reduction methods.  Alternatively, a CR Saturn IB would be under $40 million.

[Proponent]

Surely those figures depend strongly on the production rate.

[RocketmanUS]

I think if the shuttle had not been developed, we would have retreated to LEO anyway.  Whether the Saturn IB would have survived, much less any other versions of Saturn hardware is doubtful.

Probably we would not have continued going to the moon.

A plausible course of action would have seen Saturn Is flown to expenditure and manned flight would have moved to the Titan IIIC which could have put Apollo Capsules into orbit, albeit shortfueled or better yet, with a smaller SM.

As an adjunct, Saturn Vs could have been also flown to expenditure, orbiting a new Skylab designed for long term continiuous operation and expandability.  There were two V's left over after all post Skylan, and they could have put up a sizeable station.

The ironic thing to me is that Titan III/IV could have orbited current ISS sized modules that were carried by the shuttle.  These could have been configured in such a way as to require minimum orbital assembly - just dock them.

Perhaps in this world, Dyna-Soar could have been resurrected or morphed into a reusable vehicle launched by Titan and, in a flight of fancy, the Titan Boosters made recoverable, though I doubt that would have been a cost saving, but may have been good public relations...

With 4 high bays in the VIB and two pads, USAF and NASA payloads could have flown without much interfering with each other.

We then could have flown a very Russion-like program in which Apollo and Titan III were continuously upgraded as was the Soyuz booster and spacecraft.

Perhaps then we would also have perfected the ability to use EOR to return to the moon.

Just one man's opinion.

Titan used solids, smaller volume payloads, less mass to orbit compared to INT-20 and INT-21 ( INT-21 up to 255klb to LEO ).

http://www.astronautix.com/data/satvint.pdf
Am I reading page 15 ( PDF counter , page 7 on bottom of page ) right that a three engine INT-20 cost $60M to launch back in the later 60's.

So what did A Titan IIIC cost? To compare.

$72 million in 1969 according to the documents I have.

The CR INT-20 would have had its cost reduced to $55 million, thanks to the reduced costs of the F-1A and J-2S along with other cost reduction methods.  Alternatively, a CR Saturn IB would be under $40 million.

So for GTO or BEO add a third stage to INT-20. That would still be better than Titan and no solids.

And the yearly fixed overhead in the late 60's?

It seems to me that the Saturn INT would have been better to stick with , less of a gap in space travel and research.

Lower cost would be seen with higher flight rates per year? Say at least 12 flights per year.



If we had kept Saturn then public might have pushed for it's use.

[Lobo]

So for GTO or BEO add a third stage to INT-20. That would still be better than Titan and no solids.

And the yearly fixed overhead in the late 60's?

It seems to me that the Saturn INT would have been better to stick with , less of a gap in space travel and research.

Lower cost would be seen with higher flight rates per year? Say at least 12 flights per year.

If we had kept Saturn then public might have pushed for it's use.

The thought of communizing is still a good one.  That was part of my thoughts earlier in this thread, which is for USAF/DoD to switch to whatever ELV rocket system NASA would have chosen in place of STS for the purposes of this thread.  Obviously Reagan mandated USAF/DoD would fly all of their payloads on the Shuttle to communize on it, which is why SLC-6 was converted for Shuttle launch at VAFB.  So something similar could have been done for Saturn derived ELV’s.  Except that if there was a problem with the Apollo capsule it wouldn’t have grounded the DoD launches too. If there was some flaw in the launcher, it might have grounded it for awhile, but since DoD didn’t have to launch their payloads with people on it like they would have had to with STS, they really could still launch if they needed to if they felt reasonably sure they’d solved the problem. Obviously they wouldn’t want to risk high dollar payloads if they didn’t trust the launcher.  But the Saturn hardware was well proven.  No reason USAF/DoD couldn’t launch their payloads on INT-20.  If there’d been some mass trimmings, and depending on the ultimate power of the F-1A, and how heavy the payload was, DoD might have been able to get it’s (typically Titan-sized) payloads into orbit with a 2XF-1A INT-20. (anyone know what the performance of a 2XF-1A INT-20 would be?  OR if it could even get itself off the ground?) 

The same if Saturn 1B had been chosen.  A 3rd stage, like a centaur, could have been added to either INT-20 or Saturn 1B when necessary for DoD payloads too.  SLC-6 could have been converted from Titan to INT-20 or Saturn 1B instead of to STS for polar launches.  INT-20 was over powered for most DoD playload which were launching on Titan.  Saturn 1B probably would have been a better fit for them.  But, Titan was pretty expensive if I understand correctly?  Part of the reason is was replaced by Atlas V and Delta 4?  And if communizing and streamlining could get INT-20 down near the price of a Titan, then would it matter much if it was over powered?

[RocketmanUS]

http://www.astronautix.com/lvs/satint20.htm

(2) F-1 engine on INT ~36klb to LEO

The site mixed up kg for lb on their chart.

1st stage S-1C would launch part fueled, less than the 3 engine. 4 engine would have launched with more fuel than three engine model.

For smaller payloads Delta II or launch multiple payloads at same time on the INT-20/21. Other option is to launch smaller payload and send extra fuel to a depot if it were available.

````````````
We needed to launch a space station so we had a place to go to. Then they could have justified making shuttle or at least a space program.

Saturn/Apollo with Air Force using the hardware to along with commercial launches ( as shuttle was to launch ) would have given us this opportunity. Commercial and international partners could have utilized the launch ability in the 70's and not waited for shuttle in the 80's or ISS after 2000.

Apollo CSM
Widen and stretch the SM with smaller main engine to use as a payload bay for cargo ( different masses on different INT models ). Might have used the LEM main engine, throttleable.

For Lunar, add another main engine and lengthen SM for added fuel to be it's own EDS, no S-IVB needed, launch on the 5/5 INT-21. Use the stretched SM for an EDS for the Lunar lander ( crew or cargo version ).

Later make an LEO 7 person capsule ( reusable ) and a 4 person Lunar capsule to use with the new SM. Done in stages, not all at once. Capsule needed more modern tech so best to do that part later as tech evolved. New for main propulsion and power, the rest to be on the reusable capsule to lower cost.   

[Downix]

Surely those figures depend strongly on the production rate.

That is based on existing production rates, no increases for either.

Also, is not including the overhead.  Titan had about $380 million in overhead to Saturn's $440, but Saturn is for both boosters and Titan is for the entire Titan family.

[Lobo]

http://www.astronautix.com/lvs/satint20.htm

(2) F-1 engine on INT ~36klb to LEO

The site mixed up kg for lb on their chart.

1st stage S-1C would launch part fueled, less than the 3 engine. 4 engine would have launched with more fuel than three engine model.

For smaller payloads Delta II or launch multiple payloads at same time on the INT-20/21. Other option is to launch smaller payload and send extra fuel to a depot if it were available.

````````````
We needed to launch a space station so we had a place to go to. Then they could have justified making shuttle or at least a space program.

Saturn/Apollo with Air Force using the hardware to along with commercial launches ( as shuttle was to launch ) would have given us this opportunity. Commercial and international partners could have utilized the launch ability in the 70's and not waited for shuttle in the 80's or ISS after 2000.

Apollo CSM
Widen and stretch the SM with smaller main engine to use as a payload bay for cargo ( different masses on different INT models ). Might have used the LEM main engine, throttleable.

For Lunar, add another main engine and lengthen SM for added fuel to be it's own EDS, no S-IVB needed, launch on the 5/5 INT-21. Use the stretched SM for an EDS for the Lunar lander ( crew or cargo version ).

Later make an LEO 7 person capsule ( reusable ) and a 4 person Lunar capsule to use with the new SM. Done in stages, not all at once. Capsule needed more modern tech so best to do that part later as tech evolved. New for main propulsion and power, the rest to be on the reusable capsule to lower cost.   

Ok, that’s right, I’d seen that somewhere and forgot where.  That’s about 16.2mt to LEO, roughly the same as Saturn 1B.  With two F-1A’s, I imagine that would be more like around 20mt, with less propellant short load.  I wonder what the S-IC with 2X F-1A would cost vs. the S-1B?  If having just two engines would get it closer to the S-1B cost per stage? 

The S-IC thrust structure could be modified and lightened to have the center engine mount and associated plumbing removed completely.  As INT-20 it wouldn’t launch with more than 4 engines, and four F-1A engines put out about the same power as five F-1’s. 
Or it could just be left as is with no modifications (cheaper with no development at all), then a 3-engine variant would have 3 engines across and be centerlined, rather than having the 4 corners minus 1.  But with gimballing engines, I would think they could counter the slightly off-line thrust in that configuration, so I don’t think that would be a problem. (look at how off-centerline the thrust of STS and Energyia/Buran were).

I’m sorta liking that vs. Saturn 1B in our hypothetical post Apollo alterative history.
The four engine version could get 60mt to LEO.   We could build a great Space Station with that, (60mt modules) send a LEO Apollo there on the 2 engine variant.  Work on refurbishing/reusing the S-IC.  And when we’re ready to go back BLEO, we could do it with A two launch scenario.  If it were a lunar mission, then launch the CSM and Lander on one launch put into orbit by the spend S-IVB.  Then launch a full S-IVB on another launch (less some propellant for the stage to get itself into LEO), EOR, then burn for the Moon.  With the two clean pads at KSC, the launches could be done in short order of each other so the S-IVB EDS didn’t need to loiter in LEO very long before doing the TLI burn. 

If we developed a LEO version of the Apollo SM, make it more like Orion’s, large enough to get itself back from the Moon, but that it wouldn’t be tasked with performing the LOI burn any more.  So when/if a new lunar program came around, the same smaller SM could be used that had being used for years as a space station Taxi.  (the CM would have to be modified back to BLEO flight).  The smaller engine and propellant load could be used to boost the space station on every crew rotation.  Or perform TEI during BLEO missions.