Apollo: The Case for the Saturn C-3

[Athelstane]

Is it not correct to say that the Saturn V rocket had a 100% safety record but the Apollo capsule did not. The fire in Apollo one could have happened whether it was on to of the 'stack' or not if the same tests were being carried out. That I think is the important differentiation here.

Well, first, there is the case of Apollo 6, discussed just above, which is a little more complicated...it is at least arguable that it was a LOM, and certainly would have been had crew been aboard. Still, it was a test flight, and it showed why we have test flights. On its 11 operational flights, the Saturn V had an excellent record.

As for Apollo, it might be worth distinguishing between the Block 1 and Block II capsules. The Apollo 1 fire happened on a Block 1. The only time a Block II capsule ever had a serious problem was on reentry on the ASTP mission, and even that was really a crew error (though maybe that speaks to a design weakness).

 

[Bureaucromancer]

In principle I have to agree that the C-3 is incredibly attractive... but EOR really doesn't seem likely to have met the deadline.

The timeline I'm playing around with at the moment (with apologies to E of Pi et al for the blatent use of Eyes Turned Skyward concepts while ripping off For All Mankind) is Nixon taking the third path in 68 and choosing a lunar base as the next program. In practice this means the choice of Saturn V as THE manned program going forward, an immediate block buy of a further 12 Saturn V's (taking the ~4/yr production rate from the era that provides V's through to roughly 1975) in essentially a Block II configuration that doesn't change the vehicle much at all; X-24C is also funded as a bone to shuttle advocates. The point for the purposes of this thread is that by the mid to late 70s the Saturn IB fleet is expended, there is no launch vehicle really suitable for crewed operations in LEO and the X-24C is raising a lot of concerns about the viability of a shuttle, all at the same time that NASA is thinking about a LESA like hab and a real second gen Saturn V. Enter a program that merges the Saturn V-23(L) with a Jarvis/C-3 single stick configuration, Titan-III not appealing to a NASA that is more inclined to piggyback what COULD be LEO operations onto Moonlab and advocate for manned planetary flybys than try to build big LEO stations. So essentially, Saturn V and lunar operations continue, but the budget constraints are real and a real obstacle to do much more than flying to the moon a couple times a year (the architecture I envision is actually that around 75/76 the lunar return amounts to a pair of dual launch missions per year, using LM Shelters and a wet lab Moonlab).

tl;dr is that I love the C-3, but Saturn V was the right choice when the mode decision was made. The real shame is that it didn't get revived at some point, be that as an over-sized Saturn IB replacement, shuttle LRB, Jarvis, etc.

 

[Polish Eagle]

In principle I have to agree that the C-3 is incredibly attractive... but EOR really doesn't seem likely to have the deadline.

The timeline I'm playing around with at the moment (with apologies to E of Pi et al for the blatent use of Eyes Turned Skyward concepts while ripping off For All Mankind) is Nixon taking the third path in 68 and choosing a lunar base as the next program. In practice this means the choice of Saturn V as THE manned program going forward, an an immediate block buy of a further 12 Saturn V's (taking the ~4/yr production rate from the era that provides V's through to roughly 1975) in essentially a Block II configuration that doesn't change the vehicle much at all with the X-24C as a bone to shuttle advocates. The point for the purposes of this thread is that by the mid to late 70s the Saturn IB fleet is expended, there is no launch vehicle really suitable for crewed operations in LEO and the X-24C is raising a lot of concerns about the viability of a shuttle, all at the same time that NASA is thinking about a LESA like hab and a real second gen Saturn V. Enter a program that merges the Saturn V-23(L) with a Jarvis/C-3 single stick configuration, Titan-III not appealing to a NASA that is more inclined to piggyback what COULD be LEO operations onto Moonlab and advocate for manned planetary flybys than try to build big LEO stations. So essentially, Saturn V and lunar operations continue, but the budget constraints are real and a real obstacle to do much more than flying to the moon a couple times a year (the architecture I envision is actually that around 75/76 the lunar return amounts to dual launch missions per year, using LM Shelters and a wet lab Moonlab).

tl;dr is that I love the C-3, but Saturn V was the right choice when the mode choices were made. The real shame is that it didn't get revived at some point, be that as an over-sized Saturn IB replacement, shuttle LRB, Jarvis, etc.

If one has the Saturn V production line open, why not use a Saturn INT variant for LEO ops?

 

[Bureaucromancer]

If one has the Saturn V production line open, why not use a Saturn INT variant for LEO ops?

The short version is that the Saturn LRB is absolutely the project lead in this timeline.

Most scenarios I can come up with that use INT (and don't completely change the funding environment in the 70s and 80s) end up with INT-20 and no Saturn V. The concept here is a plausible scenario under which the SV sticks around. The other path I can see this taking reasonably would be to go ahead with Apollo/Titan for LEO, but for that to make sense you need to justify Congress going for both a substantial lunar and LEO program simultaneously in the back half of the 70s, which I have a hard time picturing. The high concept is that Nixon preserves lunar exploration by making Saturn V THE NASA vehicle and the late 70s gets an inversion of the inability to do BLEO missions under STS.

The way I see this playing out is that the Saturn IB fleet is stretched (by producing a couple extra SIVB stages) through Skylab, ASTP, ASTP 2 (Skylab/Salyut, enabled by there being no Saturn V shortage) and a leo test program for Moonlab, with no clear LEO plan beyond that. By which point a few extended duration LM Hab lunar surface missions have flown and a LESA like base is the project for the 80s. The combined Booster/C-3 program looks like a way to piggyback a form of LEO access on Saturn V upgrades for lunar base construction when it becomes clear a shuttle isn't in the cards without giving up on the Moon (with the nice benefit that this twin F-1 booster looks like a very nice platform for unmanned deep space). The equivalent to the shuttle design evolution in this timeline being a fight between thge enhanced Saturn V with a 10m SIV stage lunar base advocates want and a common core Saturn using the dual F-1 260" core that looks like a cost reduction strategy OMB would approve of (how much of a hammerhead do you think a 260" dual F-1 stage with four common core boosters handle?)

I tend to think that Common Core would look very attractive for a while but run into serious cost issues when the reality of redesigning for S-II for increased payload with reduced diameter (and no M-1 engine) hits.

Bear in mind that none of this is a true C-3, in that I'm using the 260" diameter proposed for Saturn V boosters and used on the SIVB rather than the 8.8m that was planned earlier. In other words, it much more closely resembles the 1980s Jarvis proposal than something out of the early 60s.

PS: I didn't mention the Saturn II option for LEO, and frankly my thoughts on that boils down to two threads. On the one hand I don't think there is money for HG-3, and on the other I think that a Saturn II that needs SRB's basically defeats the purpose, given the S-II's price. The bigger issue with this TL IMO is ARJ260 and INT-05 (the Constellation architecture in 1981 anyone?). At the end of the day I don't have a good answer for why an F-1 booster would be the path chosen, frankly all else being equal it wouldn't be. The best answer I can come up with for the moment is common core, and this sort of issue is one of the big reasons this is still something I'm playing with rather than a TL I'm trying to actually write.

 

[Dathi THorfinnsson]

Nixon might have gone with a different space program. But the Saturn V was a Democratic program, and he was highly unlikely to revive it.
If you had a different Republican president, who didn't take things so personally, maybe.

 

[Bureaucromancer]

Nixon might have gone with a different space program. But the Saturn V was a Democratic program, and he was highly unlikely to revive it.
If you had a different Republican president, who didn't take things so personally, maybe.

I'm a long way from convinced of the role that Nixon's grudge keeping played in killing Saturn V, but that is actually an angle I might take for the TL above... It certainly helps to address my questions about a 2xF-1 stage vs ARJ260 and the reasonableness of actually doing Common Core instead of INT-20 and boosters.

So:

Nixon demands common core be chosen as a single rocket for all NASA use in 68 that doesn't have the Democratic heritage... With Saturn still the program of record a couple new SIVBs and additional CSMs become possible and all the Apollo era hardware can be expended. Saturn IB first stages become usable (the two unused Saturn V's aside, there were four IBs with varying levels of first stage completion that either lost their SIVB to Skylab or never had one built). Saturn V SA-515 launches Skylab B as ASTP 2, 514 closes out Apollo with 18 as a polar reconnaissance mission aimed at based location selection with the LM derived observation/polar insertion module funded under the lunar base program. The IBs can be allocated in different ways, but I picture a pair of joint missions to ASTP 2 before the invasion of Afghanistan kills that and another two going to an experimental wet-lab (I'm thinking this gets docked to Skylab).

Single Stick C-3 can probably be flying by the time the IBs are expended, but whether it has much purpose is an open question. I'd think that a lunar return with dual launches by Saturn triple cores is feasible around the time Shuttle started flying historically. Plotting it out this way I'm thinking that LESA, a LEO station and some kind of reusable tug is the original plan and things get cut back to a lunar wet lab with crews delivered by logistics flights carrying LM Shelters and a classic Apollo EOR with the LM Taxi rendezvousing with the shelter on the surface.

In this scenario I do wonder about the S-II stage. Would a twin engine SIVB be enough for a triple core to deliver Saturn V like payloads to the moon? If not, how about a larger number of engines in a stage and a half configuration? Cross feed on the boosters would definitely help, but the potential need for a 260" S-II replacement seems like a pretty big risk to the whole program.