What if Apollo/Saturn Had never been Cancelled?

[mike robel]

Here from Astronautix.com are the cost figures for the Saturn IB vs several Titan variants.  I am too lazy today to search out the calculator that woiuld convert them to constant dollars, but it provides the idea.

I was surprised that the Titan IIIC did not match the Saturn IBs load and note that it took to the Titan IVB to pretty much match it.

Still, a smaller service module - maybe even the Titan IIIC Transtage - could have made the difference for LEO.

Saturn IB:  LEO Payload: 18,600 kg (41,000 lb) to a 185 km orbit at 28.00 degrees. Development Cost $: 1,002.200 million. Launch Price $: 107.000 million in 1965 dollars in 1967 dollars.

Titan IIIC:  LEO Payload: 13,100 kg (28,800 lb) to a 185 km orbit. Payload: 3,000 kg (6,600 lb) to a GTO. Failures: 5. Success Rate: 86.11%. First Fail Date: 1965-10-15. Last Fail Date: 1978-03-25. Launch Price $: 18.000 million in 1985 dollars. Flyaway Unit Cost $: 66.700 million in 1965 dollars.

Titan IIIM:  LEO Payload: 17,000 kg (37,000 lb) to a 185 km orbit. Launch Price $: 22.000 million in 1965 dollars.

Titan 34D:  LEO Payload: 14,515 kg (32,000 lb) to a 185 km orbit. Payload: 5,000 kg (11,000 lb) to a GTO. Failures: 2. First Fail Date: 1985-08-28. Last Fail Date: 1986-04-18. Launch Price $: 150.000 million in 1985 dollars. Flyaway Unit Cost $: 126.550 million in 1994 dollars.

Titan IVA:  LEO Payload: 17,700 kg (39,000 lb) to a 185 km orbit. Payload: 6,350 kg (13,990 lb) to a GTO. Launch Price $: 400.000 million in 1985 dollars. Flyaway Unit Cost $: 89.360 million in 1997 dollars.

Titan IVB:  LEO Payload: 21,680 kg (47,790 lb) to a 150 km orbit at 28.60 degrees. Payload: 5,760 kg (12,690 lb) to a GEO. Development Cost $: 15,800.000 million. Launch Price $: 432.000 million in 1985 dollars. Flyaway Unit Cost $: 84.300 million in 1996 dollars in 1999 dollars.

[RocketmanUS]

INT-20 with two engines would not be that much cheaper. INT-20 in the above posts above was said $55M and Saturn 1B $40M without overhead cost.

Page 13 reply #187 by Downix
Quote
"F-1 was roughly $6 mil each, H-1 was $1.1 mil each from the numbers I read.  F-1A would reduce the cost to $4.8 mil each and the H-1's replaced with their evolved form, the RS-27, dropped it to $900k, roughly."

So for the added mass to orbit why not just use the 3 engine INT-20, launch two or more things at once.

For BLEO ( Lunar ) replace the S-IVB with a hypergolic EDS ( an enlarged SM with 2 engines ). Either launch crew to LLO and back towards Earth or a LEM to TLI with it. The new LEM would not to much mass for a larger SM being the new EDS to place the LEM to TLI. From their the LEM would bring it's self to LLO then the Lunar surface ( max 15klb cargo or ascent module to surface ). Launch on INT-21 5/5.

Keep in mind that there would be more cargo landings than crew landings for Lunar. So better to just have them launch separately. Crew capsule would do a LOR with the crew version LEM.

The new capsules LEO and BEO would need to be able to fly automated full flight.

All hypergolic, no boil off problems. Plus we know we can transfer that propellant in space from one craft to another if needed.

[mike robel]

Another direction could have led to "On To Mars" as Spiro Agnew said in the firing room after the launch of Apollo 11.  These pages show the Launch Campaign for a Mission to Mars including the spacecraft launch, the 5 Nerva stages for the orbital cluster, and Saturn IBs to assemble the thing.

From Interplanetary Manned Spacecraft Concept Definition Volume II, which is available on the Nasa Technical Reports Server.  There are 6 volumes in the entire report.

Contrast this to Stephan Baxter's Book Voyage in which Lunar program is shut down after Apollo 14, Nerva fails, and an all chemical option is followed with an orbital cluster of 1 SII with 4 J2s, 2 SII derived External Tanks, and SIVB, and a mission module based on Skylab. which would have taken 5 Saturn V Launces for the modules and several more for the fuel delivers.

Along with this there are Skylab missions, a Moonlab (Skylab in lunar orbit) with which the Soviets send a Soyuz to dock with, having finalliy perfected the N-1, before a short program of about 5 manned launchs culminates in a single manned flight to Mars, landing in 1986,

[Lobo]

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

*snip*

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.
 
 

They should have had me making the decisions then.  With my magical “hindsight is 20/20” glasses on, all of this would have been so obvious.  ;-)

Yea, I can’t disagree that you are probably right on the money on all of this.  Just because people –should- have known better, doesn’t mean they did.  Even the same brains who put a man on the moon, even as absurd as that sounds when you say it out loud.

Kerolox maybe have seemed like “old tech”, and hydrolox as the way forward, but the Shuttle had to have high-powered boosters to get it’s shiny new and high performance hydrolox stage core off the ground.  That part was evident even in early concepts of a shuttle.  And they already had one.   But they ended up with the most “old-school” tech there was in solids.  They already had a large hydrolox external tank/stage in the S-II.  And the concept was explored because I’ve seen it’s concept art.  Somehow a brand new core with brand new boosters and brand new hydrolox engines won out.  Seems absurd looking back, but obviously they had their reasons, real or imagined, for STS turning out the way it did. 

As for your comments about a reusable space vehicle, I think it was more they –really- wanted a fully reusable SSTO vehicle.  When that showed to be too far beyond capability, then they went down from there.  I think the LV itself being at least partially reusable was as ingrained as the spacecraft itself being reusable.  Otherwise they could have just put a shuttle on top of an INT-20 (smaller), or INT-21 (STS sized), and been done with it.  And like I said, they did explore that.  I’m assuming it didn’t seem reusable enough, which is why they went with what they did.  And why they didn’t some better kerolox LRB’s instead of the SRB’s.  And chasing that LV reusability Dragon spiraled STS out of control.  Once they had SRB’s, then suddenly the CT wasn’t powerful enough to transport it plus mobile launchers with UT’s on them like Saturn.  So the pads had to be modified to have fixed towers, which then prevented them from launching anything else other that STS.  A sad spiral.  The whole clean pad and ML concept of KSC was such a great design.  The final blow I imagine was when the RS-25’s proved to need far more refub time between flights than they thought, and same with the SRB’s.  They probably expected the Shuttle to just roll into the OPF, get an inspection.  Some minor repairs were applicable, then rolled right to the VAB for restacking.  Same with the SRB’s.   
Too bad someone in power didn’t take a good long look at that Apollo CM after it’d been fished out of the sea after reentry, and scratched their head, and though, “hey…maybe reentry and a dip in the ocean isn’t going to be as marginal of events as we are thinking.  What if the SRB’s need a lot of refub work between launches?  What if the Shuttle and RS-25’s need a lot of refub work between flights?  What then?

As I’ve said previously in this thread, it’s also too bad someone didn’t take a look at the misconception that a winged space plane that looked like and airplane, and think that that HUGE TPS system, wings, tail, etc, doesn’t do any darn good until the very last little bit of each mission.   And that maybe a large reusable capsule would have been better?  Something like Big Gemini.  Something about the size of the Shuttle cabin, with a 20 deg. Wall slope like Dragon (I think Gemini has something like that too).  It could have a robotic arm, even a small payload bay for limited unpressurized downmass.  It could landed with a parafoil or parasail like Gemini was originally intended.  A ‘soft wing’ that wouldn’t be a detriment to the mission prior to it being needed for landing.  Could also do a propulsive landing like a larger version of Dragon.  We could have had a reusable spacecraft that pretty much did much of what the Shuttle did, but would have been much more simple and cheap. 

I know you are probably right on your overall analysis, but stop raining on my little parade!
;-)

Good comments though…

[RocketmanUS]

I'll go with a large Dragon like capsule over Big Gemini.

There is also the Kistler K-1 upper stage. Develop something like that for cargo up and down and crew to launch on a separate model. Have it be in  the US on top of the S-1C 4 or 5 engine model. No wings, forward section down for reentry and a land-landing for reuse. Like the K-1 the top part is separated on the ground , cargo or crew version. Crew version to have a pusher escape system. If not used then fuel for station and or in orbit use.

Mars better in the 90's for better tech ( life support ). INT-21 to launch to LEO assemble platform ( also used for satellites to BLEO or other assemble ). Propulsion hypergolic for long term reliable in space use, no boil off, and low cost development. Able to transfer propellant from one propulsion stage to another as needed. All stages fire at LEO for max thrust and transfer unused propellant to the stages that would be used later in the mission. Also give time to develop a lander and ascender, probes first and need equipment. Unused fuel from landers could be used by an extra ascender ( back up ). U.S pay for lander and ascender, international could pay for and make probes and habitats.

[Archibald]

So what did A Titan IIIC cost? To compare.

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

Astronautix is not that reliable - payload and cost wise. It is better to check the figures in the original documents 

I have rather different numbers... $12 million to $24 million for a Titan III.

http://www.secretprojects.co.uk/forum/index.php/topic,2881.msg140868.html#msg140868
(where Ryan Crierie did a rather fine compilation of Saturn cost numbers)

http://books.google.fr/books?id=pQ1Q9ylf818C&q=%22Titan+IIIC+costs%22&dq=%22Titan+IIIC+costs%22&hl=fr&sa=X&ei=5vfaT-K_CciG0AXvnfjNCg&ved=0CDkQ6AEwAA

http://www.google.fr/#sclient=psy-ab&hl=fr&prmdo=1&tbm=bks&source=hp&q=%22Titan+IIIC%22%22cost%22%22million%22&pbx=1&oq=%22Titan+IIIC%22%22cost%22%22million%22&aq=f&aqi=&aql=&gs_sm=e&gs_upl=27609l27609l3l27967l1l1l0l0l0l0l0l0ll0l0&prmdo=1&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=4e867ff6f8b4df97&biw=1024&bih=598

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

The site mixed up kg for lb on their chart.

Now that's interesting. For a long time I had issue with the 2*F-1 INT-20. The maths just doesn't worked ! The S-IC alone was 2000 tons+ fully loaded... now a F-1 is 700 tons of thrust; three of them, fine; but two of them ?!! 1400 tons of thrust to lift a 2000 ton stage ?
Admittedly, one could unload propellants but still - what a waste.

Astronautix numbers for the INT-20 can be traced back to three original documents (all three easily available on the web... I have them on my HD)
- a) page 8 of "selected methods for uprating Saturn vehicles"
- b) page 5 of "Saturn V derivatives"
- c) page 23 of "studies of improved Saturn V vehicles and intermediate payload vehicles"

Interestingly, a) and c) only mentions 3, 4 and 5* F-1s Saturn INT-20.
b) mentions a 2*F-1 INT-20 (that's were Mark Wade got the pounds wrong !)
- 36 000 pounds when limited to 4.68 G... too light for Apollo.
- 60 000 pounds if acceleration limited to 6G... harsh for the astronauts.

Sure, a 2*F-1 INT-20 could fly, but by offloading so much propellants, the thrust / payload / acceleration ratios were rather poor...

And that maybe a large reusable capsule would have been better?  Something like Big Gemini.  Something about the size of the Shuttle cabin

Bingo. I tend to see Big Gemini as a "fly alone" shuttle cockpit.

[RocketmanUS]

A 2 F-1 INT would not be a good launcher over the 3 or 4 engine version.

Replace Saturn 1B with INT-20 3/1 or 4/1 with new throttleable F-1A engines and J-2S. 4/1 to be used with a second payload or enlarged SM with payload in it.

With 3 MLP they should have had no problem in launching 6 INT's per year with the 2 launch pads.

If that cost is true for Titan IIIC it still has less mass to orbit per launch and smaller fairing over an INT. It would have been good for the smaller payloads ( non space station payloads ). Keep INT and Titan IIIC with upgrades over the years.

That order of 30 launchers of INT version would have given 8 extra launchers from what we needed from my earlier post for a follow on station from Skylab. With the larger SM to carry supplies ( a Cygnus like pressurized container would have reduce the amount of flights needed , use a robotic arm to attach it to the station ). That could of helped support for another station, one used for storage and space assemble. Man tended only when needed to be. Crew to transfer between stations in an orbital transfer vehicle based on a Apollo CSM, only used in space by crew ( crew not launch on ), not heat shield, cabin stretched ( CM ) back to add more room for crew and small engines to replace the large main engine for LEO operation.

With added funding to NASA back in the 70's and spend domestically would that not have helped the U.S. economy and had a greater return to the Federal revenue for the next year?

With an earlier permanent space station that should of help with education as far as kids wanting to learn. Giving them a place to put their education to work. 

[RanulfC]

I know you are probably right on your overall analysis, but stop raining on my little parade!
;-)

Good comments though…

Hey as long as I'm "right" I'll be happy

Seriously I'm not MEANING to rain on the parade, I really do find the thread and alternative fascinating. But by the same token I find the "mentality" of a lot of the early Space Program and even before that with the people who were "just" doing theory, as much if not more fascinating!

You're very much correct about the mentality "wanting" SSTO, staging was something we'd "have" to do until we got those wonderous Atomic Rockets up and running. When that didn't work out as well as had been hoped the same mental track started running around using LOX/LH2 despite the real and practical problems that propellant combinationi had.

It was in evidence even as recently as the 1990s when the idea of a LOX/RP-1 or (horrors!) H2O2/JP8 SSTO came out. Why the very idea you could even consider SSTO without the blessed combination of LOX/LH2! Blasphmy! or worse

Worse yet the "biases" were passed down by the "big" names in rockets as "fact" with usually no argument or even discussion. Reading the histories, the reports, the studies, even comments and opinion pieces you see so much infighting, back-stabbing, and down-right meanness it's amazing we got ANYTHING done at all

There are examples from one letter sent by a founder of JPL to the Department of War claiming that anyone who suggested spending money on "Liquid Rocket" development was out to sabatoge the war effort and should be shot! (Everyone knows solids are safer and much easier to develop, he said so! )

One of my favorites where some "big" names were asked to evaluate H2O2 as a rocket propellant by the government since the British were working that angle and seeming to have a lot of success.

Well these folks all "knew" that H2O2 was just nasty stuff and that the US government shouldn't be fooling with it, (beyond THAT they tended to get into fist fights over what type of rocket and which propellant they DID need to be developing but... ) so they simply made a request that the Army build them a tank to store the H2O2 in first.

They specified a simple stainless steel tank surrounded by a protective revetment in the middle of an empty field. Once delivered they had the vent valve removed and the opening welded shut and filled it with H2O2 and then went to "study" how to go about working with the stuff.

Good sized tank, open field, hot sun, no vent.... So when the tank blew up a couple of days later they wrote up a nice concise report on the obvious and numerous dangers of H2O2 as a propellant and recommended that the government NOT fund development of motors or rockets using it. (This is of course AFTER it's been used for a decade or so and has powered the X-1 for several flights)
Obviously the Brits were just CRAZY people

But keep going! Don't let me slow you down

Randy

[Archibald]

You're very much correct about the mentality "wanting" SSTO, staging was something we'd "have" to do until we got those wonderous Atomic Rockets up and running.

When that didn't work out as well as had been hoped the same mental track started running around using LOX/LH2 despite the real and practical problems that propellant combinationi had.

It was in evidence even as recently as the 1990s when the idea of a LOX/RP-1 or (horrors!) H2O2/JP8 SSTO came out. Why the very idea you could even consider SSTO without the blessed combination of LOX/LH2! Blasphmy! or worse

Worse yet the "biases" were passed down by the "big" names in rockets as "fact" with usually no argument or even discussion.

 Reading the histories, the reports, the studies, even comments and opinion pieces you see so much infighting, back-stabbing, and down-right meanness it's amazing we got ANYTHING done at all

I did some research about H2O2 because I found Mitchell Burnside Clapp "Black Horse" and other concepts very interesting.
And your post is just spot on !

I found that in 1975 in-flight refueling of a space plane was studied by Boeing and Martin Marietta, under a contract from Langley.
But the spaceplane was to be shuttle derivative, hence it had to use SSME, hence LOX/LH2... cryogens that are a pain in the b*tt to transfer.
Unsurprisingly, the study concluded IFR was not worth the pain.
The only non-LOX/LH2 space plane I'm aware of is Martin Astrorocket of 1965, which ran on hypergols.

Burnside Clapp himself got interested in H2O2 through David Andrews, a british engineer that had worked on the Black Arrow. In 1990 Andrews wrote a seminal paper based on his Black Arrow experience

Advantages of Hydrogen Peroxide and a Rocket Oxidant

I think Burnside Clapp interest for H2O2 started there.

[M_Puckett]

Titan had one HUGE cost advantage during the late 60's that helped it over Saturn. 

It shared an actual production line with the ICBM that was being mass-produced.

[mike robel]

Been looking for this for a while.  From the Space Shuttle Decision.

It seems clear that the Saturn IB line was dead in favor of Titan IIIC and its derivatives, as seems clear by this quote from below:

"The Titan III brought the prospect of wasteful duplication, for it competed directly with NASA's Saturn I-B. This Saturn carried over 36,000 pounds to low orbit. The Titan III-C, the first operational version, had a rated payload of 23,000 pounds; its immediate successor, the Titan III-D, raised this to 30,000. In addition to this, the projected Titan III-M promised to carry as much as 38,000. Nevertheless, as early as 1967, the President's Science Advisory Committee noted that "the launch costs of the [Saturn I-B] are about double those of the Titan III-M." [NASA SP-4012, Vol. III, pp. 27, 39; Thompson, ed., Space Log, Vol. 27 (1991), p. 125; Quest, Fall 1995, p. 18; Long, chairman, Space Program, p. 36.]"

While manned operations are not discusses, the agreement surely seems to spell doom for the Saturn IB.  One coiuld infer then, that while Saturn IB woiuld most likely be replaced by Titan IIIC, D, or M for lofting Apollo to LEO, the Saturn V in our little alternate timeline could have perhaps been sustained for use by NASA had we decided not to both abandon the moon and develop the Space Shuttle.

Interestingly, there is concept art of DynaSoar being lofted by Saturn I Block II.

http://www.nss.org/resources/library/shuttledecision/chapter05.htm

The Air Force and NASA
In 1494, the Treaty of Tordesillas divided up the New World by drawing a line down the Atlantic, with Spain claiming lands to the west of this line and Portugal claiming lands to the east [Durant, Reformation, p. 264]. The activities of NASA and the Air Force lent themselves to similar demarcation. With NASA emphasizing Apollo while the Air Force dealt largely with satellite reconnaissance in low orbit, there was little overlap between their concerns. However, these two agencies did not run independent programs; there was a great deal of cooperation.

This cooperation was particularly strong in the realm of launch vehicles. In launching automated spacecraft, the most important such vehicles were derived from the Thor, Atlas, and Titan ballistic missiles; both NASA and the Air Force used these rockets repeatedly, and procured them from the same contractors. They also shared in ongoing developments that increased their payload capacities.

As early as February 1961, an agreement between NASA's James Webb and the Pentagon's Roswell Gilpatric stipulated that neither agency would initiate the development of a new launch vehicle without first seeking the consent of the other. Then in 1962, a joint NASA-DoD Large Launch Vehicle Planning Group issued a report that contained a recommendation: "The 120-inch diameter solid motor and the Titan III launch vehicle should be developed by the Department of Defense to meet DOD and NASA needs, as appropriate in the payload range of 5000 to 30,000 pounds, low earth orbit equivalent." [NASA SP-4102, p. 218; NASA SP-4407, Vol. II, pp. 318, 323.]

The Titan III brought the prospect of wasteful duplication, for it competed directly with NASA's Saturn I-B. This Saturn carried over 36,000 pounds to low orbit. The Titan III-C, the first operational version, had a rated payload of 23,000 pounds; its immediate successor, the Titan III-D, raised this to 30,000. In addition to this, the projected Titan III-M promised to carry as much as 38,000. Nevertheless, as early as 1967, the President's Science Advisory Committee noted that "the launch costs of the [Saturn I-B] are about double those of the Titan III-M." [NASA SP-4012, Vol. III, pp. 27, 39; Thompson, ed., Space Log, Vol. 27 (1991), p. 125; Quest, Fall 1995, p. 18; Long, chairman, Space Program, p. 36.]

Because NASA was accustomed to receiving launch vehicles that the Air Force had developed, it yielded gracefully when the Saturn I-B came under pressure. NASA had conducted the initial flight test of a Saturn-class first stage as early as October 1961, at a time when the Titan III was still at the level of preliminary study. In view of this early start, and because the Saturn I-B was essential for Apollo, NASA went on to build 14 of them, though George Mueller hoped for more as he pursued Apollo Applications. When budget cuts hit home, however, NASA abandoned the Saturn I-B and turned to the Titan III-E Centaur. It had the energy to launch large payloads on missions to Mars and the outer planets, and did so repeatedly. [NASA SP-4012, Vol. II, pp. 54-57; Vol. III, pp. 40-41; Aviation Week, August 3, 1970, p. 45.]
 

[Lobo]

Now that's interesting. For a long time I had issue with the 2*F-1 INT-20. The maths just doesn't worked ! The S-IC alone was 2000 tons+ fully loaded... now a F-1 is 700 tons of thrust; three of them, fine; but two of them ?!! 1400 tons of thrust to lift a 2000 ton stage ?
Admittedly, one could unload propellants but still - what a waste.

Astronautix numbers for the INT-20 can be traced back to three original documents (all three easily available on the web... I have them on my HD)
- a) page 8 of "selected methods for uprating Saturn vehicles"
- b) page 5 of "Saturn V derivatives"
- c) page 23 of "studies of improved Saturn V vehicles and intermediate payload vehicles"

Interestingly, a) and c) only mentions 3, 4 and 5* F-1s Saturn INT-20.
b) mentions a 2*F-1 INT-20 (that's were Mark Wade got the pounds wrong !)
- 36 000 pounds when limited to 4.68 G... too light for Apollo.
- 60 000 pounds if acceleration limited to 6G... harsh for the astronauts.

Sure, a 2*F-1 INT-20 could fly, but by offloading so much propellants, the thrust / payload / acceleration ratios were rather poor...

If INT-20 had been kept, it would have been flying with F-1A, would would have been at least 17% more thrust each, if not more in the final production model.  (I’ve heard it could have been more than the spec’d 1.8Mlb).   So flying with two F-1A’s would have been a more viable LV.

Also, with two F-1’s, if 36,000lbs when limited to 4.68G, too light for Apollo?
How so?  That’s right about the performance of the Saturn 1B.  (16.23mt)  Saturn 1B usually gets listed at about 20-21mt, but according to Steve Peirtrobon (whom I spoken with about this), aparntly the real numbers were a little above 16mt actually payload delivered to LEO.  I think the extra 4mt was the LAS tower, so the weight on the pad was 20mt, but as that was jettisoned part way up, it doesn’t really count.
Got to remember, the fully fueled Apollo CSM was about 30mt, but (if my math is correct), about 18.6mt of that was propellant for the SMME.  That leaves about 11.4mt left.  Obviously Apollo 7, Skylab 2, 3, 4, and Apollo-Soyuz were all short loaded on fuel to get up on the Saturn 1B, but they left some SMME propellant in there.  Maybe the RCS system (which had it’s own propellant tanks I believe) didn’t have enough thrust to for retro burn.  But Dragon’s do, so I dunno for sure.  Like Dragon, the Apollo SM probably could have actually been launched with no SMME or SMME propellant.  Some modified SM without those systems could have flown on it.  Maybe with a trunk like Dragon?  The S-IVB could put it into orbit without the need for any SMME burn, and then it would deobirt itself with it’s ullage motors.
So I think INT-20, even with only F-1 engines, would have been fine to launch Apollo to a space station, and for LEO operations.  F-1A engines would increase performance somewhat as well, maybe to get a legitimate 20mt to LEO.  Hopefully S-IC could go through some streamlining and cost reductions to, so it wouldn’t be such an expensive over-kill stage for INT-20 in the 2 engine variant.

And that maybe a large reusable capsule would have been better?  Something like Big Gemini.  Something about the size of the Shuttle cabin

Bingo. I tend to see Big Gemini as a "fly alone" shuttle cockpit.

Yes!  Make the payload bay something cheap and expendable.  A payload fairing at the rear of the big capsule.  Like a Shuttle, but just the cabin and payload bay.  A robotic arm could be stowed in a compartment in the aft sidewall of the large capsule, and could be extended to reach back and manipulate cargo, just like the shuttle’s, just that instead of being in the payload bay, it would be on the Capsule and reach back into the bay.  The large capsule would have a robust enough RCS system to be able to maneuver with the “payload bay” and cargo attached.  It’d have an airlock to for EVA’s,  The “payload bay” would be jettisoned prior to reentry and the robotic arm stowed and hatch closed.  The large capsule would have a good amount of internal room to bring back pressurized downmass.  It would have a simple dish TPS like any capsule that would be protected during the mission.  Then it could land either like Dragon Rider will, propulsively using it’s LAS pusher system to land.  Or it could land like was planned for Gemini, on landing gear and a parasail. 

I think it would have cost just a small fraction of what the Shuttle Orbiter did, and weighed just a fraction of what it did.  Could have launched it on a MLV like INT-20, (3 or 4 engine variant)  and still got a Space Shuttle class payload into LEO.  It could have fulfilled every role that the Shuttle did except large unpressurized downmass.  Which turns out wasn’t all that important anyway.
And INT-20 could have put satellites by itself when the Large Capsule wasn’t necessary.  The capsule would only need to launch when doing manned LEO work, like servicing a space station, satellite repair, etc.  Unlike STS where a crew needed to go up on every mission. 

[RocketmanUS]

So I think INT-20, even with only F-1 engines, would have been fine to launch Apollo to a space station, and for LEO operations.  F-1A engines would increase performance somewhat as well, maybe to get a legitimate 20mt to LEO.  Hopefully S-IC could go through some streamlining and cost reductions to, so it wouldn’t be such an expensive over-kill stage for INT-20 in the 2 engine variant.

I don't believe so as 1st stage has to much dry mass. Better to just launch INT-20 3/1 with performance estimated at around 78,000lb to LEO. Bring up fuel or second payload with the launch.

[Archibald]

From memory, the S-IC weighed 140 metric tons, dry, and 2000 tons+ fully fueled.
And yes, about Apollo too light, I tend to reason with the damn SM fully fuelled. Sure, on Skylab they emptied it - and the Block III was to have a lighter one more adapted to LEO duties, with a smaller LM engine.

I had not realised that the INT-20 could have launched so "little" payloads - 36 000, 60 000 or 78 000 pounds to orbit.

I have to say - it changes a lot of things. I can now see two ways of building a space station.

INT-20 3/1 + Apollo + space station module, single launch. Manual docking of the modules, shuttle style, by Apollo.

Or a mix of Titan III for crew and space station modules, with an automated tug for automated dockings.

Sure enough, the INT-20 (or S-IC / S-IVB) looks like a missed opportunity.
EDIT
http://nix.nasa.gov/search.jsp?R=19730033222&qs=N%3D4294957355%2B4294948255%2B4294963040

A grand tour launched atop a Saturn INT-20 / Centaur. How about that ?

[Lobo]

From memory, the S-IC weighed 140 metric tons, dry, and 2000 tons+ fully fueled.
And yes, about Apollo too light, I tend to reason with the damn SM fully fuelled. Sure, on Skylab they emptied it - and the Block III was to have a lighter one more adapted to LEO duties, with a smaller LM engine.

I had not realised that the INT-20 could have launched so "little" payloads - 36 000, 60 000 or 78 000 pounds to orbit.

I have to say - it changes a lot of things. I can now see two ways of building a space station.

INT-20 3/1 + Apollo + space station module, single launch. Manual docking of the modules, shuttle style, by Apollo.

Or a mix of Titan III for crew and space station modules, with an automated tug for automated dockings.

Sure enough, the INT-20 (or S-IC / S-IVB) looks like a missed opportunity.
EDIT
http://nix.nasa.gov/search.jsp?R=19730033222&qs=N%3D4294957355%2B4294948255%2B4294963040

A grand tour launched atop a Saturn INT-20 / Centaur. How about that ?

If Titan III wa really 1/2 the price of Saturn 1B, and it could have been made to carry a LEO verson of the Apollo CSM, then it would have made sense to go with that as the crew launcher, and then keep INT-20 for a medium lift LV, for payloads like Space Station modules.  The USAF in a sense would have been covering the overhead to produce and fly Titan (for payloads and as an ICBM), so NASA would only need to have kept the S-IC and S-IVB lines going. 

[Lobo]

Interesting.  All of this Titan talk has got me considering some things I previously had not.  I only looked at things in terms of NASA hardware.  But obviously prior to Apollo, NASA was using USAF missiles.  And I imagine that kept the cost way down as much of the overhead was paid for by the USAF.  The USAF had nothing that could go to the moon however, and so Saturn V was necessary to get it done in Kennedy’s timeline.  Once that was done, there really wasn’t much need for the Saturn V hardware, if we were just going to be hanging out in LEO for awhile.  So there would have been incentive to go back to USAF rockets, and NASA could save that rocket overhead, and build payloads instead.
However, the Saturn V hardware –did- existing, with it’s expensive development already having been paid for.  And the problem with the USAF rockets, is they weren’t all that high performance because they used solids and hypergolics.   They used a hypergolic core obviously because they were based on ICBM’s, which needed to be fueled quickly with storable propellants.  (or to be solid only, like Minuteman).  So USAF rockets were less than ideal for NASA’s needs.  And NASA’s rockets were less than ideal for USAF’s needs.  Later, the USAF splintered off their payload launching business from their ICBM business in the EELV program.  Which used rockets that wouldn’t have been good ICBM’s. 
But, that wasn’t until later.  In the 70’s, the USAF used ICBM’s and ICBM derivatives for their payload launching, and that’s what NASA would have had to choose from had they wanted to cost share with USAF.

Am I getting all of that correct?

So, their options were to keep Saturn, with it’s high overhead, and oversized (for LEO) segments, or to be restricted to the USAF’s hypergolic/solid ICBM derived rockets, or to create a new, cheap reusable Space Transportation System, that would suit their needs better than the USAF hardware, but be affordable enough to maintain themselves.

Wow, the latter really does seem like a good idea, huh?  Too bad everyone so horribly miscalculated.  Either of the first two options would have been far cheaper as it turns out than STS.

If a reusable shuttle was on the brain, apparently there was a concept to use Titan as the Shuttle booster by Martin Marietta.

http://www.pmview.com/spaceodysseytwo/spacelvs/sld036.htm

I don’t really like their drop tank concept though, but maybe it would have worked.  Might have been better to put J2S engines on the orbiter, with a smaller ET-like hydrolox drop tank.   Or perhaps NASA could have kept the S-IVB line, and modified it to be the Orbiter in-line upper stage, and expended the J2S.   It was more expendable then they probably wanted, but most of the booster would have had it’s overhead paid for by USAF.  And instead of developing the new segmented STS SRB’s, they would have been using the existing Titan SRB’s.  Perhaps they cold have actually sandwiched a pair of Titan IIIM cores with boosters together as the 1st stage booster. 

Still, It would have been better to modify Apollo for LEO operations, and to be reusable.  With a smaller/lighter/cheaper SM, so that Titan III could have carried it.  Maybe they should have cancelled all the Saturn V hardware, taken ALL of the budget to build new Space station segments building off of lessons learned in Skylab.  And then launched them on the Titan III family.  If it could get 20mt to LEO, then we could have built a station with segments the size of the ISS.  But on rockets who’s cost of operation was paid for by USAF.  Kind of sad to see the Saturn hardware go that way, but maybe that would have been the way to go?  The shuttle cost so much, it was forever before we could think about really doing something big with it like the ISS. 
Then NASA could have transitioned to EELV’s along with the USAF.

Which brings up the more recent point of SLS.  As much as I like it, I really think we could have done now, what we could have done in the 70’s with Titan.  Except the EELV family is much better suited for payloads.  Really the only trade study that should have been done was the cost of evolving EELV’s up to the Atlas VP2 variants, or AJAX, and just have used existing AV boosters in various combinations.  Either way, NASA would have had to pay for some overhead, unless USAF had a need for AVP2, which I don’t think they do.  AJAX probably would have gotten a lunar class program going faster, although evolved EELV’s might have been the most cost effective in the long run, with the maximum amount of cost sharing.

[mike robel]

There was also Titan IIIL2 and Titan IIIL4 vehicles which used 15 foot cores, each with 4 engines + 2 or 4 SRBs.

http://www.aerospaceprojectsreview.com/blog/?p=66

[Archibald]

If a reusable shuttle was on the brain, apparently there was a concept to use Titan as the Shuttle booster by Martin Marietta.

http://www.pmview.com/spaceodysseytwo/spacelvs/sld036.htm

I don’t really like their drop tank concept though, but maybe it would have worked.  Might have been better to put J2S engines on the orbiter, with a smaller ET-like hydrolox drop tank.   Or perhaps NASA could have kept the S-IVB line, and modified it to be the Orbiter in-line upper stage, and expended the J2S.   It was more expendable then they probably wanted, but most of the booster would have had it’s overhead paid for by USAF.  And instead of developing the new segmented STS SRB’s, they would have been using the existing Titan SRB’s.  Perhaps they cold have actually sandwiched a pair of Titan IIIM cores with boosters together as the 1st stage booster. 

Through Denis Jenkins landmark shuttle books, I've learned of something strange about the shuttle.
That the orbiter design was frozen months before everything else - the engines, the external tank, the booster.
From mid-71 NASA knew their orbiter would have a delta wing and a 15*60 ft payload bay... and that was it.
Still there variants of that orbiter with three J-2S, four J-2S, three SSME... and no engine at all, truly an american Buran (boosted by the Titan III-L)

Maybe they should have cancelled all the Saturn V hardware, taken ALL of the budget to build new Space station segments building off of lessons learned in Skylab.  And then launched them on the Titan III family.  If it could get 20mt to LEO, then we could have built a station with segments the size of the ISS

There was a nice middleground between the two options: the leftover Saturns !
Saturn IB: -209, -211, -213, 214
Saturn V: -514, - 515
(if Skylab B gets killed, after all there's a better station coming, no ?)

They used a hypergolic core obviously because they were based on ICBM’s, which needed to be fueled quickly with storable propellants.

Minor nitpicking: in the 70's the hypergols were not a problem, not yet. On Titan Gemini, the hypergols were even a kind bonanza - an eventual fireball would be smaller than a kerosene / hydrogen / oxygen one, leaving more room to save the astronauts.

[Downix]

There was also Titan IIIL2 and Titan IIIL4 vehicles which used 15 foot cores, each with 4 engines + 2 or 4 SRBs.

http://www.aerospaceprojectsreview.com/blog/?p=66

No, two engines, not four.  The LR-87 had dual nozzles, much like the RD-180 on the Atlas V does.

[mike robel]

Huh.  Thanks.  I always assumed two engines