If NERVA hadn't been cancelled, then a nuclear second stage on the Saturn IB could have produced a LV capable of Energia-level performance with 80-100 tonnes to LEO.
There is a definite moment when Saturn IB lost to Titan III, but it is not related to manned spaceflight but to robotic exploration. *snip*One can ask why didn't they brought back Saturn IB Centaur for Viking, the answer was that by 67-68 Saturn production had been frozen (not cancelled, just frozen) so they went for Titan III instead.
During Voyager 1.0 NASA considered Titan III for the first time, but back then they disliked military boosters because of bad experiences, notably with Atlas and Titan.
The official start of the space shuttle program was between december 1967 and july 1968, Voyager had already been cancelled (July 1967) and Viking was on very early planning stages.
What is sure is that there was a large number of Saturn IB left by Apollo (SA-209 to SA-216, minus ASTP, AS-210 in the end that's SEVEN rockets, not all them complete). But as you said, they crucially lacked the Centaur stage. Bringing back the Saturn-Centaur in 1968 would have duplicated Titan IIID-Centaur (that was the name back them, it become III-E later) but also probably the future Space Shuttle, as you noted. Surely, during its funding quest for the shuttle, NASA had very hard times proving OMB and Congress the Shuttle would bring any cost improvement compared to the Titan, so imagine if the Saturn IB was there, too. More generally, by 1968 Saturn IB was already a relic of the past, at least in NASA eyes.
I would say first scrap the shuttle and get Big Gemini as NASA space station logistic vehicle. The funny thing, Big Gemini is superficially similar to the MOL, maybe NASA and the Air Force could get a kind of hybrid of the two spacecrafts, launched by a Titan III-M.
It would be pretty easy for Martin Marietta to tweak a Titan II to replace both Atlas and Delta. The end result ? having slained the shuttle, Saturn IB, Atlas and Delta the Titan family would achieve total domination of U.S launch systems, something the Space Shuttle tried to achieve but failed. Then the Titan could try to pull a Falcon 9 - mass production to drop cost, followed by (partial) reusability to drop cost further. I would say - start from the enlarged core, four engine Titan III-L without SRMs but scrap the storable propellants and return to the Titan I kerolox LR-87. Four kerolox LR-87 topped by one kerolox LR-91, and then goes full Falcon 9, if that's ever doable in the 80's. By the way, Big Gemini makes an honest-to-god Dragon 2...
I would say first scrap the shuttle and get Big Gemini as NASA space station logistic vehicle.
Would Big Gemini have had any chance of winning out over some sort of reusable space plane during this era? I'm no expert on it, but wasn't it still basically an expendable capsule? I know there was a pretty palpable push for reusability and going "futuristic" at the time. That's why I mention an HL-20/42 style mini shuttle at the time. Or something like a larger Dyna-Soar perhaps.
1. (note: Big Gemini was a serious project, up to a full-size mockup, but only between 1967 and 1969, after what it was only OMB prefered option to scare the hell out of NASA into cutting Shuttle development costs) 2. Big Gemini crew module was to land on an airstrip, using X-15 -like skids and a parafoil or parasail. On paper it could be refurbished and reused, but that's very, very uncertain and probably not worth it. Maybe just scavenging the spent modules for cheap spares, as NAR planned to do for future Apollo CMs.
Anyway, the attached is courtesy of Dr. Logsdon.
Lobo asked for an "Alternate Joint NASA/USAF "STS" system and I totally forgot about the 'fact' they actually DID have one... But timing is everything after all USAF "SLS" (Space Launching System) of 1960:http://www.astronautix.com/s/sls.html
NASA "Almost-SLS" of 1966/68-ish:https://en.wikipedia.org/wiki/Saturn_IIIf only the 'kids' could play nice with each other Randy
Interesting. I love this site, I always learn something new.
Obviously this was the USAF preferred concept with a whole bunch of big solid boosters. Heh.
In the 50's, solids looked pretty good as big liquid engines were in their early stages. And later it was figured out that when those solids got really big, they weren't all that cheap and easy.
Yea, I was aware of Saturn II. An interesting design.
I never quite liked that it needed Solids to get off the ground with the existing J2 engines (although it could with sea level variants or the HG-3). Also, hydrolox is difficult and just not a good booster propellant.
There's a case to be made for it in STS (Or Ariane 5) where it's basically a ground lit 2nd stage/sustainer stage all the way to orbit. But Saturn II would have the hydrolox S-IVB as the 2nd stage anyway. The S-II is itself a 2nd stage rather than a sustainer stage.
It probably could have been modified into a sustainer stage with the help of a lot of solid booster assistance, then it'd basically have been a smaller, fatter 1970's SLS. heh.
With 20/20 hindsight, I still think having a kerolox booster that could get the stack off the ground efficiently would have been preferable.
With maybe small Minuteman solids (shared with other LV, small, easy to handle) that can augment it for heavier payloads. But I think SpaceX has shown, just simple kerolox, of a size to cover your whole payload range without solids is a good concept and perfectly economical (even without any reusability).
Don't over think it, keep it simple and reliable, which gas generator kerolox was in the 60's and 70's.
That's why I kind of like the "1970's Falcon 9" concept, with H-1C engines on a mono core booster, with then a single vacuum H-1 for a kerolox 2nd stage. Add the Centaur 3rd stage for BLEO payloads, and it'd have been a perfectly fine shared launcher for USAF as well, with engine family shared with Delta and Atlas for smaller payload needs.
Well there was that "Titan-variant" called Arcturus back around 1959
Kind of depends on what assumptions you're using since Aerojet could actually 'show' the math working for a big solid built IN Florida, (rather than say Utah or Colorado ) at least cost-wise. Operationally however...
QuoteYea, I was aware of Saturn II. An interesting design.I knew that YOU knew, that "I" knew, that you knew, but then again what's new?
Seriously, it was and it showed that NASA was willing to consider, (not for long but...) using such components. The main thing was the "Saturn-II" obviously being based on existing Saturn hardware whereas SLS...
True but being the 'uber-propellant' (in theory) kept it in the running on math alone Nobody 'liked' the need for solids or dense liquid boosters because they always brought the overall performance numbers down, but, (as we've seen with the Delta-IV) anything else is a bit wasteful. Despite being flaky as heck over design, propulsion, performance, and mission the one thing the AF got right from the start was hydrolox was best for anything OTHER than boosters.
QuoteThere's a case to be made for it in STS (Or Ariane 5) where it's basically a ground lit 2nd stage/sustainer stage all the way to orbit. But Saturn II would have the hydrolox S-IVB as the 2nd stage anyway. The S-II is itself a 2nd stage rather than a sustainer stage.Eh, check that. The SLS air-light the J2s once the SRBs burned out. Oddly enough it seems to be where Martin got the idea for the Titan-III and later because running the numbers showed much better performance, (with less vehicle stressing) by air-starting the liquid stages after the SRBs lifted the vehicle to altitude. There was by design no 'sustainer' stage.
QuoteIt probably could have been modified into a sustainer stage with the help of a lot of solid booster assistance, then it'd basically have been a smaller, fatter 1970's SLS. heh.You mean "SLS" not "SLS" right?
QuoteWith 20/20 hindsight, I still think having a kerolox booster that could get the stack off the ground efficiently would have been preferable.Again the answer you get depends on what answer you were looking for in the first place In the Air Force mind of the time the segmented solids had a pretty sweet draw in that by varying the number of segments AND boosters you could launch a wide variety of payloads on the same 'upper' stages. Especially if you varied the propellant load as well.
As per 'standard' planning of the time they were looking at several launches a month up to a couple a week in some cases of various mission payloads. Quite obviously everyone noted you ran into problems with 'big' boosters in that they required very specialized, and extensive, (not to mention expensive) infrastructure. As the flight rate went up some infrastructure would end up pretty much the same, (propellant production, handling and storage come to mind) for small/medium and big boosters but you didn't have to have It all right away. Having said that another 'obvious' conclusion was you eventually wanted to go with reusable, (the AF had "Astrorocket" studies going on around the same time-frame I think) but at the same time you had significantly different payload missions that were often not as 'suited' to a single launch system or design.
And a launcher that big, like the current Falcon-9 is not going to be able to service the vast amount of different payloads developed and designed between the 60s and the 80s. It will be vastly too large for some, (most actually early on) and need additional upper stages or boost assists for others. And then there's the difference between what NASA and the Air Force 'wanted' at any one time. If the USAF doesn't have a 'manned' mission to support they won't want anything over about the Titan, (10 to say 12 feet) whereas NASA who are running a manned mission
A lesson we learned again from the Shuttle. Monlithic systems tend to lead to fixed designs which don't scale well or at all whereas 'modular' can be scaled in any direction at an economic cost.
And actually I have to point out that SpaceX didn't in fact 'prove' this at all since the good-old R7 was doing it long before Elon Musk got the space bug.
The problem is a full kerolox LV is NOT efficient and the only way it stays relevant is if you can make it vastly cheaper. Which arguably SpaceX does but, in truth anyone with a more efficient upper stage and similar costs would eat their lunch.
There's a reason they are moving to methalox after all
QuoteThat's why I kind of like the "1970's Falcon 9" concept, with H-1C engines on a mono core booster, with then a single vacuum H-1 for a kerolox 2nd stage. Add the Centaur 3rd stage for BLEO payloads, and it'd have been a perfectly fine shared launcher for USAF as well, with engine family shared with Delta and Atlas for smaller payload needs.You're mixing your metaphors there buster The only reason the US had 'any' decent LVs at the time, (talking early 60s) was because they invested in LH2 upper stages and engines.