Alternate space shuttles

[Workable Goblin]

On-orbit refueling was in the planning but got tossed when things got tight. And again it's not as clear as people tend to think how it's done is the only way it can be done. A space station of some type was planned, what exactly it would be varied but several layers of on-orbit operations were planned for including orbital satellite servicing and propellant transfer operations. Even with a 'calmer' Space Race there will still be pressure to 'keep up' as long as the Soviets are making the attempt. Where things get REALLY muddy is if they don't...

The Soviets are going to be basically a non-entity, looking at their behavior IOTL. Once they hit those easy firsts they went back to focusing on military needs with lunar flights mostly being a side hustle by Korolev, then ramped up funding later when it became apparent we were serious about going to the Moon to try to avoid looking like they had fallen completely behind. If we're not going to the Moon, they probably focus on getting Soyuz and Almaz or something like it ready. No N-1, no Zond. Why bother? Maybe Lunokhod and sample return because those are "easy," relatively speaking. As the United States program starts going smoothly in '64/'65 when the Soviets aren't really doing that much (the Voskhod flights and that's about it) and people get used to the idea of spaceflight, interest in 'keeping up' will probably drop to about the level it was later IOTL, i.e. minimal. Keep flying, sure, but paying for the Vietnam War or the Great Society or whatever is more important than going to the Moon with men...

The problem was they couldn't GET a flyback stage at that point in time and so they needed to pursue other options and ocean recovery by parachute, (and braking rocket) were the early option.

In 1960, sure. In 1969, the situation is different. At the very least, Congress is probably more amenable to funding a program intended to reduce launch costs now that launches are kind of important. My proposal for replacing the S-IB with a flyback stage wasn't that von Braun would do it that way at the beginning, it was that around 1970 NASA would compromise on a flyback lower stage for the Saturn IB as an effective method of lowering launch costs because they can't get Congressional or Presidential support to build a full-scale reusable launch vehicle and their analysis shows that reusing the lower stage would be much easier and still offer a good benefit relative to reusing the upper stage (especially if they implement upper-stage cost reduction), plus it would offer them a path to move towards the fully-reusable vehicle in the future. Given that they got away with developing Shuttle, a far more technically complex vehicle, at the same time with presumably similar budgets since I am putting a butterfly net around the wider political landscape (i.e., the same people are elected and have the same general priorities), NASA is clearly financially capable of developing a kerolox flyback first stage using some kind of uprated H-1 or similar motor in the 1970s without needing any particularly extraordinary efforts on the author's part (i.e., on my part).

In any case, I'm not even sure on this versus developing an HL-10 (probably) based replacement to Apollo to serve as a station logistics vehicle for "Advanced Spacelab" (basically the American Mir) and just launching it on a cost-shaved Saturn IB, with possible future development of reusable LVs. That offers similar advantages and was something that came up as a recommended idea in some studies as a short-term method of developing reusability.

The Saturn-1/1B was baselined as the 'workhorse' LV since the budget was so tight prior to the Lunar program. It was planned to carry a lot more LEO missions than just Apollo LEO testing which is all it got OTL. The main reason that they studied adding the Centaur to the stack was to move away from the Atlas both because they were looking at new ways to use the Saturn but also to avoid conflicts as the Atlas-Centaur was supposed to be mostly for DoD use. Atlas and Titan for a time shared the cost effectiveness of their respective missile programs but Atlas was initially supposed to be the standard DoD LV especially once Centaur was added. Saturn was actually considered a 'non-military' LV despite its origins as an Army missile project, (along the same vein as the Viking/Vanguard LV) so it was going to be the main "NASA" LV for as much as could be launched on it. Of course there were payloads it couldn't launch both smaller and larger but like Shuttle later it was 'intended' to be the main NASA LV for whatever it COULD do. And like the Shuttle that's going to drive the way many payloads are designed and built which will feed back into what gets launched. (The Proton was actually more a serious "ICBM" than the Saturn and no actual planning on its use as one. It was actually a 'pure' launch vehicle from inception)

Yes, it's going to be the workhorse...for large payloads for a significantly smaller and cheaper program. It might fly more in aggregate simply because there aren't any Saturn Vs or Titan IIs running around, but that does not make a large flight rate. There just weren't that many large payloads to launch in the 1960s. A few more later on if Voyager doesn't go down to its ignoble doom, and more in the 1970s for the Grand Tour spacecraft, whatever they're called, perhaps, and of course those space station missions...but overall, still not that many flights, so it's still going to look pretty expensive.

Uhm, the M1 was actually tested and shown to work as it was an alternate missile reentry body design. (It was supposed to be a "maneuvering" warhead design but they found they couldn't control it due to the reentry plasma, and no way to use a 'sensor' system but it followed a pre-programmed course fine) Unlike the majority of the later designs there was never an attempt to get it to a 'runway' landing and subsonic speeds it was always ONLY a hypersonic lifting body design. Not until much later with the M2 series was any attempt made to have it 'glide' at low-supersonic/subsonic speeds. (At which time the 'aft' body was added to address subsonic drag issues) It was one of the few designs known to be able to use an ablative reentry surface AND still have known lift characteristics and a stable flight pattern.

I am aware that the M-1 is a hypersonic-only lifting body. It was also being abandoned for more advanced lifting designs like the M-2 (directly derived from the M-1, as you note) or the A-3 for exactly the reason that it could not safely operate at subsonic speeds by the late 1950s and early 1960s, i.e. exactly when NASA was designing Apollo. The combination of requiring more R&D, the remaining 'race' mentality, and the gap that's clearly going to exist between Mercury and Apollo operations augurs for them discounting the lifting designs and going for a capsule to save on development time and risk. Besides, Soyuz shows that a mission module is perfectly compatible and not really that difficult to integrate with a capsule design, in any case, if NASA had wanted to go that route.

EDIT: Actually, Jenkins says "By mid-1958 [Faget had basically decided on Mercury's blunt-body design]...This [M-1] concept was first presented [at the same time]...This [M-1] design was further modified in late 1958...creating the M-2 shape". (I apologize for the elisions, but there was a considerable amount of irrelevant text in between; the reference is pg. 33 Jenkins 2001). So the M-2 seems to have come within months of the first presentation of the M-1's concept, if Jenkins' chronology is to be trusted.

Incidentally, my assumption was that Apollo would necessarily incorporate a mission module, but not until a Block II for cost and schedule reasons. Block I would basically replace Gemini in testing (somewhat) longer duration flight, multi-crew operations, EVAs, etc. and basically resemble our Apollo (or, more exactly, Block III from Eyes for obvious reasons), but targeted at launching on a Saturn I. Block II would incorporate the mission module for docking, long-duration (multi week) flight, experimental space stations (based on the mission module), etc., and be targeted on the IB.

I was not aware that the M-1 was tested in-flight. Would you happen to have a source/mission name/etc.?

 

[RanulfC]

If offered, would either ULA or His High Muskness go for a Falcon-Centaur?

Musk has no plans on pushing the Falcon system so probably not. He's concentrating on the ITS and Raptor which isn't, (as designed) compatible with the Falcon. Now if they are actually working on a methane engine compatible with the Falcon that's a different story but I've not heard anything. (Despite it being a major topic over on NSF ) My "take" was probably just about as expensive to develop but I'd suggested getting a Merlin that could run on cryo-propane and LOX as it was the most (space) compatible with RP-1/LOX but had a much higher ISP. (Close to methalox actually but 'fits' in the same space as RP1)

Part of the 'issue' it would seem is a requirement to keep the 'fluids' on the vehicle to a minimum which means kerolox all around, (or methalox in the Raptor engine vehicles) and while both ULA and pretty much everyone else is talking methalox it's really not that much more difficult given the knowledge base to go with hydrolox at that point. (Where the major difference comes in is supposedly making propellant specifically on Mars and despite the "popularity" of methane production I've seen convincing arguments that's not actually the best route. It does however have better PR that most other choices )

It would seem that 'instead' Musk/SpaceX are going to go the multi-body 'reusable/recoverable' route and the Falcon-Heavy to meet the requirements of the market. We'll see how that works out

Randy

 

[marathag]

Since it hasn't been posted to this thread, I think...

Behold-- the Chrysler SERV

 

[RanulfC]

IN some cases, and in some cases not--recall that Agena was not a tug, it was a spacecraft bus that a lot of "working" spacecraft were directly derived from--so there was precedent for a "satellite" contributing on the order of a km/s or two to the insertion to LEO. Indeed historically by the time the first GSO birds were being flown in the early 60s, they had apogee kick capabilities: Syncom's performance cites an apogee kick stage critical to making orbit, and the masses suggest its performance at about 1650 m/s--quite similar to today's standard GTO.

Granted My main point was they didn't TEND to think of it unless they couldn't do it the 'right' way. They mainly saw it as a short-cut

Yes, generally, though more specifically that if a reusable single stage is just barely capable (or just barely shy) of making a certain mission, a two-stage RLV using the same technology is typically fantastic with lots of performance margin. Take SASSTO: it's a classic example of a hydrolox aerospike SSTO, and capable of lofting just barely more than a Gemini despite dry weight figures and specific impulse best described as "optimistic": 3.5 tons from a vehicle which is supposed to mass empty less than half of what the expendable common-bulkead S-IVB massed for a similar propellant load.

Pair it with an expendable off-the-shelf Centaur, though, and that payload jumps to 7.5 tons for only the marginal cost of a Centaur, which grants a lot of room for mass overruns on the first stage, and of course it opens up GTO/BEO launches. If you design a second stage also using SASSTO technology, the payload increases further to something over 11 tons, fully-reusable on both stages. A marginal SSTO has the technology to make a fantastic first-stage-only-reusable or two-stage-reusable.

Ah yes my favorite S-IVB "mod" (50% "slush" hydrogen propellant which a J2 based aerospike could handle... In theory anyway

And you're right of course but it's not the way most people "see" SSTO unfortunately and that's one of those "all-or-nothing" viewpoints that is a peeve of mine.
Compromise is NOT a dirty word and often does a better job, especially when the alternative is nothing at all.

Randy

 

[RanulfC]

Since it hasn't been posted to this thread, I think...

Behold-- the Chrysler SERV

Second favorite SSTO design Literally an "Apollo" capsule on some serious steroids, (so as to use the already known data on reentry and flight characteristics) and again what NASA actually ASKED for but not what they really wanted which is why it never got past Phase A

Randy

 

[Shevek23]

....
e of pi said:

I'm highly skeptical that the S-IB reuse plans would have succeeded. The evidence of later attempts to try to reuse stages through parachute recovery is pretty poor. I'm not saying that the H-1s would have melted in the sea water, but rather that they'd probably have problems with parachute deployment, stage tip-over on water impact, things of that sort. Solvable, perhaps, but the kind of problems that add up and add up until you start wondering why you don't just go for the flyback stage and get something that will be better, anyway.

The problem was they couldn't GET a flyback stage at that point in time and so they needed to pursue other options and ocean recovery by parachute, (and braking rocket) were the early option. While the recovery and reuse planning wasn't perfect it was quite doable at the time it was suggested. I'm not sure how much 'evidence' there is as frankly no one has gone as far as the early planning in the attempt.....they'd determined that the engine bells could actually handle the entry heating and aerodynamic loading and that the stage would actually be stable for entry as far as they could determine. Actual flight showed it was marginally stable and could have used some sort of passive stabilization device but in general the recovery plan should have worked as designed. (Unlike the Saturn-V the Saturn-1 was planned to reentry engines first in a more stable configuration) In general the Saturn-1 stage design was robust enough to handle the stress' of landing and floating till recovery the main question, (which was answered with testing) was how would the engines hold up.

In addition the way the stage was made would have made it rather easy to 'boost' performance as required by adding solid rocket boosters as was planned....

I've managed to find a reference that named the material the Saturn 1B S-1B tanks and other major structural elements were made of--Aluminum alloys mostly of course. I focused on the tank material, Aluminum alloy 5456 and compared its tensile strength and density with that of a steel of the high temperature class suited for fast supersonic vehicles mentioned in an online discussion of such planes (in the SR-17 to X-15 speed ranges) Working from memory on the latter, yield strength is in the ballpark of 1.5 GPascal, and the density about 7.85 that of water. With those figures, I find that to match the strength of the aluminum the steel would need just a bit over 1/5 the thickness--I realize that is not all good by any means! (Thinner gauge means both that it is harder to work with, at least at the low end, and that a sheet would have less inherent resistance to buckling, suggesting that stringers or other built-up methods of resistance would have to be added). However, given the relative densities, I found that the steel could be built up to 1.64 times thicker to match the weights--this still leaves the steel at 1/3 the thickness (about exactly) but at the same weight, would have a 64 percent increased tensile strength! Tensile strength is not an entirely reliable gauge of compressional strength (for thin walled tanks and beams, this relates to buckling) nor to shear strength, but I think this is most instructive.

If in fact reuse of the S-1B after recovery from post burnout descent were practiced in some ATL, the argument of the Saturn 1 design being "expensive" to operate would be weakened, while its utility would be high. Yes, if we assume a stagnant space industry--and all the arguments presented to emphasize the economics of low flight rates seem to me mainly to emphasize that space launch is not really so much a "market" as a state-sponsored enterprise, even in its ostensibly commercial missions so much is determined by state decisions--then the economics of reuse will not show up very strongly, being offset by costs such as the sea recovery operation.

More perversely, for low flight rates, the more successful one is in designing a single article that can be reused many times, the more dysfunctional the market aspects of contractor relations are--for if I can use a single stage 10 or 20 times, but only launch a few times a year, it will be many years before a second article is ever required to replace it; the contractor cannot get any economies from productionizing a design, every article is in effect custom made, and the team that made the first one has long been dispersed to other tasks and may well have left the company with no opportunity should the company even desire taking time off for training to train up a replacement in anything more than paper procedures, no hands on apprenticeship. This greatly multiplies the cost of the single reusable item and also makes contracting for it unattractive for the enterprise that does it. Indeed here is a case where a high flight rate does seem essential to decent economy.

Now OTL, Chrysler only had the chance to make 20 or so S-1 type stages, and the report I read mentioned some significant design changes between the S-1 and S-1B phases too. Each was made essentially ten at a time, maybe more to account for test articles and unlaunched museum pieces, if any.

For these reason, in an ATL where NASA is limping along between 1960 and some later date when Congress relents and lets them move on to the Next Thing at last, even considerable economies in recovering and reusing stages might not seem too apparent. I think though that success in doing this, 4 or more times for each stage in inventory, would lower overall costs below Titan III projections despite the high cost of the upper stage.

Optimistically supposing that this is recognized, both by Congress and by the commercial world interested in launching comsats and so forth, I could envision NASA contemplating making the "next thing" a continuation of the successful 1B design, but further ruggedizing the stage design in order to both allow for attaching solid boosters and for greater confidence that a stage will indeed be used many many times.

Noting then that replacing the aluminum material with a high-temperature steel at zero added weight but with a near 2/3 increase in strength, and that the steel has considerably better strength at high temperature than the aluminum would, I could suggest the next batch of new S-1 type booster stages be made out of such a steel in lieu of aluminum. As an auto firm, I think Chrysler might be better placed than most astronautic firms to adapt to a steel, although of course this is a high grade of high temperature steel probably significantly different than typical auto body steels. (As an Army contractor however they might have some experience with it in tanks and other heavy duty military kit).

Again the problem is, the whole point of going over to steel is to increase the durability of the stage, to multiply its reuses, and even with a very high flight rate, the redesign for steel is going to cost, the processing in manufacturing may be more costly, the material itself might be (but that is a minor factor; even titanium would cost as just raw material a tiny fraction of the total bill to make these) and the number would be limited.

But still consider--let's say NASA cannot envision being funded for more than 4 launches a year. But DoD is, perhaps against their will, instructed to switch over to using Saturn 1 based tech (they might be encouraged to substitute alternative upper stages, to integrate into the standard S-1 shape of course) and their annual launches count too now. Since I am postulating NASA realizes small but still significant savings versus rival all ELV systems, private industry can plan on realizing at least these too if NASA or a spun-off launch consortium may market the booster. They ought then to capture the entire US based commercial industry.

This means higher utilization of the reusable stages, allowing for the order placed with Chrysler to be higher and thus lower unit acquisition costs. That lowers each launch cost, higher annual utilization lowers the cost more due to amortizing other equipment, and also means more orders of whatever S-IV version is now current, lowering their unit costs in turn. What might begin as a small savings versus ELV alternatives for private customers can easily be turned into a bigger one, say 15 percent going down to 30 percent. With a Saturn launch costing only 70 percent of the best value ELV, the industry might be more encouraged to design bigger satellites, that cost more to build but deliver better performance, with they money they save on the launch, as well as I have argued to launch more of them due to getting more service per capital dollar invested, hence higher profits.

Since this is a thread about "shuttles" which I think we can reasonably generalize to mean "launch vehicles attaining superior economy through partial or full reuse of components," I think suggesting such virtuous circles here is not inappropriate.

 

[RanulfC]

The Soviets are going to be basically a non-entity, looking at their behavior IOTL. Once they hit those easy firsts they went back to focusing on military needs with lunar flights mostly being a side hustle by Korolev, then ramped up funding later when it became apparent we were serious about going to the Moon to try to avoid looking like they had fallen completely behind. If we're not going to the Moon, they probably focus on getting Soyuz and Almaz or something like it ready. No N-1, no Zond. Why bother? Maybe Lunokhod and sample return because those are "easy," relatively speaking. As the United States program starts going smoothly in '64/'65 when the Soviets aren't really doing that much (the Voskhod flights and that's about it) and people get used to the idea of spaceflight, interest in 'keeping up' will probably drop to about the level it was later IOTL, i.e. minimal. Keep flying, sure, but paying for the Vietnam War or the Great Society or whatever is more important than going to the Moon with men...

Can't disagree really and because the Soviets are needed to 'drive' the Americans... Competing space stations is possible but it really depends on what can be done within the budget given and IF that budget exists. (BTW: was the 1962 budget before or after the 'supplements' granted for Kennedy's lunar program?)

Really I'll point out I'm one of the ones who has suggested we might STILL have not gone to the Moon in an alt-2017 under without the Sputnik and Gagarin panic

In 1960, sure. In 1969, the situation is different. At the very least, Congress is probably more amenable to funding a program intended to reduce launch costs now that launches are kind of important. My proposal for replacing the S-IB with a flyback stage wasn't that von Braun would do it that way at the beginning, it was that around 1970 NASA would compromise on a flyback lower stage for the Saturn IB as an effective method of lowering launch costs because they can't get Congressional or Presidential support to build a full-scale reusable launch vehicle and their analysis shows that reusing the lower stage would be much easier and still offer a good benefit relative to reusing the upper stage (especially if they implement upper-stage cost reduction), plus it would offer them a path to move towards the fully-reusable vehicle in the future. Given that they got away with developing Shuttle, a far more technically complex vehicle, at the same time with presumably similar budgets since I am putting a butterfly net around the wider political landscape (i.e., the same people are elected and have the same general priorities), NASA is clearly financially capable of developing a kerolox flyback first stage using some kind of uprated H-1 or similar motor in the 1970s without needing any particularly extraordinary efforts on the author's part (i.e., on my part).

My point though was they could already have a 'recoverable/reusable' booster from the start which is what they wanted. And from there it's questionable they'd get the support to change to a fully reusable system or get support to make an reusable upper stage or either, or neither. It could very well end up similar to OTL where they WANT to re-do the whole system and end up with a compromised and flawed design as a result...

And I'd say that 'extraordinary effort' on the authors part is acceptable... Except YOU have written a timeline and all I have is copious notes so point taken

In any case, I'm not even sure on this versus developing an HL-10 (probably) based replacement to Apollo to serve as a station logistics vehicle for "Advanced Spacelab" (basically the American Mir) and just launching it on a cost-shaved Saturn IB, with possible future development of reusable LVs. That offers similar advantages and was something that came up as a recommended idea in some studies as a short-term method of developing reusability.

Or a Dynasoar based vehicle Really it depends on how it's pitched and what is the actual (versus political/idealized) requirements. Most of the general circumstances are comparable to OTL at that point and there's no more guarantee the same basic decisions would be made TTL as OTL. Which is why I tend to push for an earlier attempt at recovery/re-usability is so that there is a more realistic basis for such decisions.

Yes, it's going to be the workhorse...for large payloads for a significantly smaller and cheaper program. It might fly more in aggregate simply because there aren't any Saturn Vs or Titan IIs running around, but that does not make a large flight rate. There just weren't that many large payloads to launch in the 1960s. A few more later on if Voyager doesn't go down to its ignoble doom, and more in the 1970s for the Grand Tour spacecraft, whatever they're called, perhaps, and of course those space station missions...but overall, still not that many flights, so it's still going to look pretty expensive.

"Significantly smaller and cheaper" doesn't have to mean lesser though as it was possible to do more, especially as the original assumption was a 'need' for larger manned system. It rapidly would be obvious that automated is more effective but that hasn't prevented OTL NASA from prioritizing manned over automated where they could do so. OTL the major issue has been we "skipped" over so much initially that trying to go back and re-do the parts we skipped has never really been supported. Granted that it would be more difficult to justify expansion in a far less severe "space race" environment but it would actually be a bit easier to justify/argue as incremental steps rather than 'new' programs. In some cases it will be a 'large' jump, (orbital ops to a space station for example) but it's relatively straight forward and a 'logical' sequence.

Of course it depends a great deal on who's doing the pushing and what they are pushing (A MOL type space lab versus a Von Braun wheel for example )

I am aware that the M-1 is a hypersonic-only lifting body. It was also being abandoned for more advanced lifting designs like the M-2 (directly derived from the M-1, as you note) or the A-3 for exactly the reason that it could not safely operate at subsonic speeds by the late 1950s and early 1960s, i.e. exactly when NASA was designing Apollo. The combination of requiring more R&D, the remaining 'race' mentality, and the gap that's clearly going to exist between Mercury and Apollo operations augurs for them discounting the lifting designs and going for a capsule to save on development time and risk. Besides, Soyuz shows that a mission module is perfectly compatible and not really that difficult to integrate with a capsule design, in any case, if NASA had wanted to go that route.

EDIT: Actually, Jenkins says "By mid-1958 [Faget had basically decided on Mercury's blunt-body design]...This [M-1] concept was first presented [at the same time]...This [M-1] design was further modified in late 1958...creating the M-2 shape". (I apologize for the elisions, but there was a considerable amount of irrelevant text in between; the reference is pg. 33 Jenkins 2001). So the M-2 seems to have come within months of the first presentation of the M-1's concept, if Jenkins' chronology is to be trusted.

I recall seeing the M1 mentioned in missile RV testing but not sure where, (and frankly now that I go back and look my notes are hugely unhelpful as usual, I resolve the only use for time travel is to kick my own butt on NOT taking advantage when I had the chances ) which is why I noted that it was not the M1 that came forward to manned design. And I trust Jenkins on when it came to that point as it makes sense in the timeline. The M2 as noted was specifically to get a design that 'might' be capable of subsonic flight and landing and as I understand it based on work from the original contractor that had added an inflatable section to the M1 design which NASA then tested in a wind tunnel along with a rigid aft section. (The rigid section performed much better hence the move to the M2 instead of an M1 and inflated aft section)
(Ok general question to the thread, someone had an internal magazine called IIRC "Contrails" and I seem to recall seeing the history of the M1 design and the inflatable aft section concept in an article of that magazine. Anyone know which company that was? I want to say Convair but I'm not sure)

Anyway what NASA "asked" for was a fairly simple reentry vehicle with some cross range capability which the M1 was a rather straight forward and simple lifting body vehicle. What they 'needed/wanted' was actually a capsule which is why Martin provided one as a alternative. Again a more recent example is the Orbital Spaceplane Program, NASA specifically required and requested a "spaceplane" but given the parameters what they NEEDED was a capsule and which Boeing provided. Even the eventual 'winner' (LM) noted in their final report, (on their last 'lifting body' design which morphed after winning into a hypersonic lifting body recovered by parachute and retrorockets, sound familar? ) that despite the "spaceplane" designation what best fit the NASA criteria was in fact a capsule design. The only parameter that could not be met with a capsule was the cross-range and in either case it was the least 'graded' requirement but the one deemed initially the most important for 'controlled' landing. It was specified because the recovery of the Mercury was pretty expensive, especially if NASA had to pay for it themselves.

It was one of the three 'options' for a possible "lifting" space craft with the other two being the lenticular design concept and a 'winged-body' that were the origins of the Dynasoar. The M2 had issues even then at low speed, the lenticular had space issues and frankly the winged-body was what the 'concept' was based on so it was little surprise that was the one proceeded with.

Incidentally, my assumption was that Apollo would necessarily incorporate a mission module, but not until a Block II for cost and schedule reasons. Block I would basically replace Gemini in testing (somewhat) longer duration flight, multi-crew operations, EVAs, etc. and basically resemble our Apollo (or, more exactly, Block III from Eyes for obvious reasons), but targeted at launching on a Saturn I. Block II would incorporate the mission module for docking, long-duration (multi week) flight, experimental space stations (based on the mission module), etc., and be targeted on the IB.

Probably but in fact the NAA design was the only one that did NOT incorporate one in the initial design. But since it was the only one that had Faget's preferred capsule design as a baseline concept...

I was not aware that the M-1 was tested in-flight. Would you happen to have a source/mission name/etc.?

My notes say it was a tested RV candidate for maneuvering warhead but not proceeded with. I recall seeing it in line drawing of early RV designs but no idea where though it was, as we've noted, a popular early design for an RV with some cross range and apparently known characteristics. It wasn't dropped until attempts were made to bring it down into the subsonic regime where it had to be significantly modified from the original shape. (And in the end it wasn't as effective in that role anyway so I question why bother?)

Randy

 

[Shevek23]

Regarding the steel version of the S-1...call it S-1S perhaps? S-1F? For "ferrous?"

At 5/3 the strength with the same weight, I figure it could handle another 500 tonnes of sea level thrust in the form of two solids attached to it that deliver that much with very very little modification. After all, it already has a cluster structure, with a "spider" grouping them together to distribute forces, so if the spider can take an extra 65 percent or so, 500 tonnes should not strain it beyond its basic overall design strength, with safety factor similar to the S-1B in normal operation.

Looking at Titan III, the solids for it were about twice this force, and thus could not be used. Something about half the thrust would be desired. I figured with similar mass proportions though we'd be looking at 22.3 tonnes dry, 120 tonnes propellant for each, to make the burn time match that of the core stage closely. With such figures and vacuum Isp of 270 (similar to Shuttle SRB) and the standard S-IV on top I get about 26.4 tonnes to LEO, or nearly 40 percent improvement on the standard S-1B.

Surely there is no need to go to steel structure to enable attaching solids to the aluminum S-1B stage, but the steel allows boosters of this type with no increase of the core dry mass whatsoever. Realistically there would be some, for the actual attachment members I suppose, but it would have to be more to beef up the spiders in an AL stage.

Hasn't it been bruited about that 30 tonnes to LEO is all you really need for a good space program? We'd nearly have it. Actually with a 13/8 improvement in launch thrust, we could make an expanded S-IV type stage, I figure we'd just be on the cusp of wanting to add another J-2S engine so doing so, we can get more tonnage, but not it turns out dramatically more; still I think it just hits the 30 tonne goal, at the cost of having to design and order a special and thus more expensive new stage. But with just the standard mass S-1 (steel or aluminum) and a Centaur stage we could launch very significant tonnages to GTO, the Moon or deep space.

To be honest the big liability here is that one cannot efficiently launch the much smaller payloads typical of the market demand in the 1980s. But if prices come low enough we could always simply scant the propellant load in a standard S-IV for whatever small loads we like.

Interestingly, eliminating the S-IV and putting a Centaur right on top of the S-1 can deliver 9 tonnes to low LEO, 3.5 tonnes to GTO and 2.5 on an escape parabola, which is virtually similar to a hyperbolic Lunar transfer orbit. This would involve the S-1 stage burning out at a higher speed and altitude than with a normal launch burdened by the 140 tonne mass of the upper stack of course, and thus subject it to worse thermal heating when aerobraking, which is something to consider carefully. But hey, stuff like this is why I wanted to make the S-1 stage out of steel!

@RanulfC, reading what you've said about the plans to recover the S-1 stages OTL by parachuting and rocket-braking to a gentle splashdown with the engines down I better appreciate why you so strongly react when people suggest the need to protect the engines. Such a scheme would have left the engines soaking submerged several meters below the sea surface for as long as it took for a ship to hove to and haul it. In fact IIRC you were in favor of just dragging in through the water back to port without even hoisting it onto the deck!

Your confidence that NASA knew what it was doing when estimating that the stage as a whole, being made of aluminum as it is, could be expected to come thorough aerobraking and a tour of the Atlantic or Pacific sea water in reusable condition gives me great confidence in the whole splash-recovery concept, if one works out the aerodynamics for stuff like tumbling properly. Making the stage of steel instead of Al makes me think even more extreme treatment such as high speed burnouts could still leave it more times reusable.

The idea of the engines being submerged still bothers me though, notably the turbo machinery. The nozzle and chamber are probably all right I guess. Mightn't be a good plan though to separate off the turbo machinery and put the systems for each one inside a sealed compartment just above the basic gimbal mounts, with pairs of high pressure LOX and fuel lines going down to the separated chamber-nozzle arrangement now acting as a pressure fed system, with each one having its own turbomachine set rigidly mounted above?

I figure at something just under 40 tonnes dry, the stage will sink a bit under 1/10 its tank length into the water. With engines and thrust structure on the bottom, how stable is this "buoy" from tipping over? Even if it does list of course the engines will not be shifted around much.

 

[Workable Goblin]

Can't disagree really and because the Soviets are needed to 'drive' the Americans... Competing space stations is possible but it really depends on what can be done within the budget given and IF that budget exists. (BTW: was the 1962 budget before or after the 'supplements' granted for Kennedy's lunar program?)

The FY '62 budget would have begun July 1st, 1961 (before 1976, the FY began on the first of July and ended on June 30th) so...maybe, given that Kennedy announced Apollo on May 25th. On the other hand, there really would have been little concrete idea of what the lunar program actually entailed by July 1st (never mind whenever the budget was actually passed), so I doubt it actually was a major factor in FY '62. FY '63 and beyond, yeah, but not FY '62.

My assumption with the budget was that, as I said earlier, it would crest at or a little higher than the historical upper limit on post-Apollo budgets (roughly $20 billion in inflation-adjusted funds) in the mid-'60s, then gradually decrease to '70s levels between then and the mid '70s, then more or less continue as usual. I figured thanks to the residual race mentality there would still be some pressure to pour money into the space program--just not nearly as much as OTL.

And I'd say that 'extraordinary effort' on the authors part is acceptable... Except YOU have written a timeline and all I have is copious notes so point taken

"Extraordinary effort" was meant to refer to justifying how NASA could afford to do whatever program the author wants. Doing so would not really be required for a flyback kerolox stage given OTL events.

Or a Dynasoar based vehicle Really it depends on how it's pitched and what is the actual (versus political/idealized) requirements. Most of the general circumstances are comparable to OTL at that point and there's no more guarantee the same basic decisions would be made TTL as OTL. Which is why I tend to push for an earlier attempt at recovery/re-usability is so that there is a more realistic basis for such decisions.

Trouble is that the Dyna-Soar program is still probably going to be canceled due to the lack of military utility, and there doesn't seem to have been much interest in reviving the design for Shuttle IOTL. There was, on the other hand, considerable interest in using the lifting-body shapes to build a mini-shuttle of some kind or another. So HL-10-based mini-shuttle seems much more likely to me than a Dyna-Soar-based equivalent.

Of course it depends a great deal on who's doing the pushing and what they are pushing (A MOL type space lab versus a Von Braun wheel for example )

I was certainly assuming the former, not the latter. That, at least, was a subject they were realistic on as they began to learn more about spaceflight.

 

[MichaelWest]

Even so, the design team did not initially assume they would get access to or have the budget to build a bigger booster though that rapidly changed as NASA got going.

Note: "I" claim the title of "Saturn-1/1B Fanboi" here and on NASAspaceflight.com, and I'm still in the running for the title concerning the "Big-Atlas"

Seriously I'm hoping for some timelines using both more extensively. Heck for that matter I'm wanting to see someone use the "Flyback Atlas" concept while we're at it:
http://www.aerospaceprojectsreview.com/catalog/spacedoc52.jpg

Randy

I admire both Atlas and Saturn, the first appears to be an elegant exercise in using less for more while Saturn may be a "kludge" but it achieved more with less. In my thoughts these two would likely have been the foundations for military and civilian space launches where the USAF and NASA stay divorced. Without the Apollo push we know I think Saturn V may never be built and a more modest yet hopefully less spasmodic program would see Saturn I/IB and its evolution serve US well. Now in my imaginations for a rather different ATL I use the two (Atlas/Titan vs Redstone/Saturn) conceptually (not so much the as built hardware) to ponder how a German (not Nazi) versus American program might have evolved (I assume the USSR runs about the same). Atlas is grounded in American technology and method just as Saturn shows the influence of Von Braun and its "German" heritage. Saturn shows how a limited budget might force the development to build on what you had just as the A4 formed the basis for the later thoughts on getting bigger. My assumption is that the USA can always out spend, the USSR has more resources but only just and any other "Great Power" is some fraction of the American effort so economy is king if you want to run or win. So I get a three-way (four if the Anglo-French pursue a program too) space race. It makes it fun looking at the paper proposals that might get ground where more programs are competing. So thank you for indulging the queries on Saturn.

 

[fasquardon]

because the Soviets are needed to 'drive' the Americans...

That's a good point. The Soviets really were the ones driving the race.

Maybe the best way to change the US Shuttle is to have the Soviets develop a shuttle as their reaction to Kennedy's moon challenge? So instead of the Proton, N1 and other such elements, they spend the resources on basically an earlier version of the Zenit and LKS for space station operations (and, down in the fine print, to practice the skills needed for building a moon ship from multiple launches). Say one of the influential decision makers in the Soviet program says "we can't catch up to the Americans before they land first, our only hope to stay in the race is to leapfrog them".

Again, that is straying into the 1959-1969 period though, and I'd like to keep focused on the post-1969 period.

I've always been a big fan of the possibilities of the Saturn IB rocket.

As WG says the place for kerolox TSTO is if you're focused on LEO, (which is why Falcon-9 is a 'problem' for SpaceX IMHO) and not higher orbits or BEO. While the original Saturn/Juno-v was planned simply as a booster stage with a 'variable' set of possible upper stages, many based on existing missiles, (Atlas and Titan initially) it really required the LH2 S-IV/B to gain its full potential. Adding SRBs wasn't really 'cost-effective' with anything less than the LH2 upper stages and once it became clear that was the way to go NASA went with it. Similarly Atlas and Titan ended up having to include a Centaur stage to put significant payload to higher orbits and this was realized early on which is why Centaur was developed in the first place

Hmm. It required the SIVB? What I read is that the SIV was forced on Von Braun and his team by the USAF's efforts to stymie to rocket. So they were forced to develop an expensive new stage that they didn't need and had to replace in a few years anyway. The replacement SIVB, naturally was based off the design of the SIV. I strongly question if the upgraded second stage of the SIB would have been LH2/LOX fueled without the USAF's attempt at sabotage.

I've managed to find a reference that named the material the Saturn 1B S-1B tanks and other major structural elements were made of--Aluminum alloys mostly of course. I focused on the tank material, Aluminum alloy 5456 and compared its tensile strength and density with that of a steel of the high temperature class suited for fast supersonic vehicles mentioned in an online discussion of such planes (in the SR-17 to X-15 speed ranges) Working from memory on the latter, yield strength is in the ballpark of 1.5 GPascal, and the density about 7.85 that of water. With those figures, I find that to match the strength of the aluminum the steel would need just a bit over 1/5 the thickness--I realize that is not all good by any means! (Thinner gauge means both that it is harder to work with, at least at the low end, and that a sheet would have less inherent resistance to buckling, suggesting that stringers or other built-up methods of resistance would have to be added). However, given the relative densities, I found that the steel could be built up to 1.64 times thicker to match the weights--this still leaves the steel at 1/3 the thickness (about exactly) but at the same weight, would have a 64 percent increased tensile strength! Tensile strength is not an entirely reliable gauge of compressional strength (for thin walled tanks and beams, this relates to buckling) nor to shear strength, but I think this is most instructive.

This looks wrong. Aluminium has a higher strength/weight ratio than steel. Or at least, this is true when comparing similarly priced equal weights of steel and aluminium alloy. Given that you are talking about steels for the SR-17 and X-15, I wouldn't be surprised if they were using some seriously fancy, expensive stuff.

Hasn't it been bruited about that 30 tonnes to LEO is all you really need for a good space program?

By me, yes. Or at least, that's what I reckon is needed for a good space program that could realistically expect to be funded in the 20th Century. One could construct a moon ship in around 3-5 launches of such a rocket, launch larger space station modules, useful mini-shuttles and interestingly sized probes and scientific satellites without breaking the bank.

Once doing anything beyond robotic exploration of the bodies beyond Lunar orbit, manned flybys of Mars and Venus or building serious infrastructure in Earth orbit (like SPS satellites and BIG space stations), Energia and Saturn V class rockets start looking awfully good.

________

So a general question for folks: has anyone ever seen any discussion of the Saturn IB being considered for use as a launcher in the 70s or beyond after 1968?

And I wonder if the SII stage on the Saturn INT-19 could have been made reuseable? The J-2 apparently showed no signs of wear no matter how long NASA ran it for, if the J-2-SL and the HG-3 showed similar robustness, recovering the expended stage, or at least the engines, might make an INT-19 type vehicle an attractive LV for a mini-shuttle.

fasquardon

 

[Workable Goblin]

Hmm. It required the SIVB? What I read is that the SIV was forced on Von Braun and his team by the USAF's efforts to stymie to rocket. So they were forced to develop an expensive new stage that they didn't need and had to replace in a few years anyway. The replacement SIVB, naturally was based off the design of the SIV. I strongly question if the upgraded second stage of the SIB would have been LH2/LOX fueled without the USAF's attempt at sabotage.

The Silverstein Committee that decided that developing the conventional upper stages for Saturn was a waste of time and money met in late 1959, when the transfer of Marshall to NASA was a foregone conclusion, so I don't see what the Air Force had to do with the decision (yes, analysis of hydrolox stages had begun earlier under the Air Force, but the actual decision to develop them wasn't made until then). Not to mention that the Committee quite conclusively demonstrated that hydrolox stages had massively superior performance to any kerolox stage. They persuaded von Braun of the merits of hydrolox, so it was at least a willing submission.

Once doing anything beyond robotic exploration of the bodies beyond Lunar orbit, manned flybys of Mars and Venus or building serious infrastructure in Earth orbit (like SPS satellites and BIG space stations), Energia and Saturn V class rockets start looking awfully good.

I think improving flight rates is still the better solution there. More exactly, if the program expands past routine orbital operations it would make more sense to replace a Saturn IB or IB+ rocket with a shuttle with similar capabilities but the ability to fly more often for less money than to develop a Saturn V or Energia. You have to go really huge to get much benefit from that size of rocket, and there's little real likelihood of that happening anytime particularly soon. (Needless to say, I think Elon would have been better off working on new Falcon-sized rockets than on BFR)

 

[RanulfC]

So a general question for folks: has anyone ever seen any discussion of the Saturn IB being considered for use as a launcher in the 70s or beyond after 1968?

And I wonder if the SII stage on the Saturn INT-19 could have been made reuseable? The J-2 apparently showed no signs of wear no matter how long NASA ran it for, if the J-2-SL and the HG-3 showed similar robustness, recovering the expended stage, or at least the engines, might make an INT-19 type vehicle an attractive LV for a mini-shuttle.

fasquardon

Saturn-1B? Why when you have the "God-of-all-rockets" the Saturn-V available? We laugh at such pitiful payload... What? That got canceled too? (IIRC the Saturn-1 line was shut down around '65 and the last Saturn-Vs came off the line in the late 60s with no follow on orders) Well we can still use parts of it right? (Hence "Saturn-II" and the "INT" series) Eh, qualified maybe at best? Fine we'll start over with a shuttle, a space station, then back to the Moon and on to Mar... No? What do you mean "no"? That's like stopping after Columbus discovered America... (It's NOT but you'll note they literally used that trope in "Apollo 13" no less ) Fine, a shuttle, space station and the Moon... What? Again? All right a space shuttle and space station.... No again? What it this 'budget' thing you keep going on about and speaking of where's our money... FINE! (Come on guys we've ALL heard that one right? ) A Shuttle to make access cheaper, (muttered) but we're going to Mars as soon as you get over this little 'phase' your in...

Somewhat seriously, one of the things that I think WG and I are talking past each other on is what constitutes 'reusable' and that's actually "time-period" dependent I think. Prior to the Lunar program "reusable" meant a more basic "able to reuse the vehicle" even if it had to be fished out of the ocean. Sure getting the entire vehicle back to the launch site intact and turning it there was a 'better' option once you thought about it seriously but "everyone" already KNEW how this was going to go. "Reusable" was a lot more flexible early on in that hte exact method of getting the stages back wasn't as important as the idea that you would 'recover-and-reuse' to reduce costs. (Because it's silly to throw away such expensive stuff )

Both recovered and flyback were initially suggested, (keep in mind METEOR was proposed in the 54-56 range and METEOR Jr. shortly after but Von Braun's Collier's and Disney was around the same time and the basic concept of "recovery" was as noted baked-into the thinking) what wasn't as clear is if recovery would be as straight forward as assumed. (By this time the "X" vehicles had shown that early assumptions were optimistic to say the least) Still, 'recovery' is the basic idea and whether it's by fishing the stage out of the ocean or flying it back to the launch site it is a requirement of "reuse".

As knowledge grew and the issues became clearer but by the early-to-mid-70s NASA was optimistic (overly so really) the technical challenges could be addressed and 'technically' they weren't "wrong" at any rate, just a bit premature. But worse was the attitudes had significantly changed and flyback was now synonymous with 'recovery' rather than just one option, further the Lunar program had 'baked-in' both an attitude and expectations that weren't quite eye-to-eye with reality shall we say.

Which brings us to the "INT" or Intermediate (also "Interim" as in in-between) booster concepts which essentially tried to cherry-pick keeping parts of the Saturn-V going. Yes it's quite possible the INT-19 could have been ocean recovered if the thinking had been there but it wasn't. Essentially the INT vehicles were considered expendables with "mass-production" and "cheap" components making up for not being recoverable like the "shuttle" would be. They would 'supplement' the "shuttle" not compete with it. But that ran into the rather obvious economics issues and since 'reusable' equaled cost effective any requirement for a non-reusable LV rapidly dissipated. Goodbye Apollo/Saturn legacy...

This is why I tend to NOT focus on the "post-1969 period" as IMHO NASA has been 'ruined' by the Apollo program and the PoD's needed to get to a viable "alternate" shuttle are so significant Yes you might be able to finagle a RSU "Lifter" with the 'proper' thinking the problem is that thinking isn't really what was being thought at the time. You might be able to change course to an ETS outcome using an "expendable" architecture but that needs to drop the recovery concept. But...

To get to an "alternate shuttle" at this time will take several fundamental changes both in direction and thinking but also in the way "recovery/re usability" is defined within thinking and how it all relates to an effective "post-Apollo" space program. As it is once the Apollo/Saturn legacy gets tossed (which as I pointed out is required to get the economics of the flight rate) and "recovery=full-recovery" thinking the assumed "minimum" requirements end up being significantly hefty. And that's where NASA was coming from at that point, so really, regardless of what the Air Force 'officially' wanted NASA was mostly there anyway. (Actual cooperation from the beginning would have been nice but past history meant that didn't happen till much later when the Shuttle was officially "inevitable" anyway. Earlier requires someone to step up and officially be the adult which was NOT either NASA or the Air Force )

And while we're at it lets assume that someone actually puts in the effort to HAVE a "space policy" beyond keeping NASA alive which is probably the crux of the issue. It was all well and good for Nixon to say that NASA had to take it's place among the other priorities of the US. The thing was nobody really held NASA to it so they never really believed it applied to them. (And being honest neither did anyone else in the government be it the military to the park service, some took longer than others ) While I think we can all agree that the IPP was significantly a bridge-to-far nothing but the "shuttle" wasn't the proper answer either and more could have been done with proper guidance from all sides.

Having said that NASA being tasked with reducing the cost of space access needed to NOT happen in a vacuum because that did not take into consideration the needs and responsibilities of the DoD which while complimentary in general are not "really" about cost but about access itself. Not having that required DoD, (NASA read this as "Air Force "which given what they weren't cleared to know made sense but was actually quite obvious to those who DID know, hence the head of the NRO basically telling NASA that the "Air Force" requirements weren't all they'd been told they were) wasn't an option but due to the nature of classified operations that wasn't made clear to NASA nor did anyone really bother to MAKE it clear. (Again the head of the NRO DID in fact try and make that clear but as he was 'only' a Undersecretary of the Air Force...)

And splitting off that 'requirement' would have quickly lead to NASA finding that the required 'economy' wasn't possible as planned so other plans would have had to be made. As I keep saying I have my doubts that would have been an acceptable outcome from the NASA management point-of-view, but it at least is a clear indication that a re-think is required. And from that NASA might have come to an alternative and more capable compromise IF the Administrative and Congressional support could be gained.

In general you're not looking at "full" re usability from the outset, (and frankly that's what we got anyway) but it needed a deeper "goal" as well to build upon.

Here's an idea, (that's been 'done' IIRC ) Have there be no IPP or push for the centers to "think big" but instead have a realistic and in-depth looks at the budget and Congressional limits for the post-Apollo period and make a realistic plan accordingly AND pitch an actual "program" as a follow up to Apollo rather than single goal "Apollo-like" program which, (like Apollo) leaves no room for anything else to be undertaken. Take the long-view instead of the short, ("less than a decade" thinking) view and plan and build support accordingly.

A modest (interim) space station and reliable, inexpensive access within resaonable limits might feel like a huge step down from the Moon but it keeps the door open and offers a sustainable way forward. (Again the problem is pitching it so an organization that sees pretty much anything BUT another Apollo like program as a failure to, well, NOT see it as a failure)

Randy

 

[RanulfC]

That's a good point. The Soviets really were the ones driving the race.

Which is why I'm not favoring not having Sputnik go up first Frankly you can keep some of the momentum if Sheppard goes before Gargarin but keeping the Soviets involved is a key factor.

Maybe the best way to change the US Shuttle is to have the Soviets develop a shuttle as their reaction to Kennedy's moon challenge? So instead of the Proton, N1 and other such elements, they spend the resources on basically an earlier version of the Zenit and LKS for space station operations (and, down in the fine print, to practice the skills needed for building a moon ship from multiple launches). Say one of the influential decision makers in the Soviet program says "we can't catch up to the Americans before they land first, our only hope to stay in the race is to leapfrog them".

"Leapfrogging" is how you don't get as sustained program though as Apollo shows In practice the Soviets run out of low-hanging fruit goals pretty rapidly and changing favor/fortunes drove the N1/Proton. Having said that I can't recall if it was here or NSF but I 'did' point out that if you put a set of delta-wings on the N1's upper stage it looks like the Colliers/Disney/Von-Braun ferry rocket so...

Problem is the Soviets pretty much chose exactly the wrong path to follow by neither committing to the Moon race nor fully choosing to NOT commit. By egging the US into actually putting forth an effort they had painted themselves into a corner that nothing less than commitment on their part was going to be seen as a credible response. Then they didn't commit. Once it's clear they can't actually keep up, (and that was Gemini not Apollo) it was pretty much to late. Hence the idea of a 'closer' race which gives them a chance and makes it a race in more than just name.

And the problem with reducing the cost of access, (a LEO "shuttle" or ferry system) is the same reason that it wasn't viable for Kennedy. At the time it would be too easy for the "other guy" to match you so it's not actually a "leapfrog" event and far to likely to result in a negative result vis-a-vis what had gone before. In the Soviet case it would be pretty obvious that their early success wasn't as much of a 'leap' as was being said it was so the choice boils down to sitting on your laurels and acting like you're 'above' a Moon race or spending the effort to actually participate. At the time the Soviets could actually afford to do neither but no one knew that but them. Committing would have shown how weak their hand was so they sat back and let history play out. (For similar reasons they would not have accepted any idea of a 'joint' mission or space program but they COULD probably parlayed that sort of effort into a delay of the American program. And there's a thought; What if Kennedy lives and manages to convince and get proposed a joint Lunar Mission? How long can the Russians string him along before it falls apart and once it does it the public and political support that drove OTL Apollo going to go with it?)

Again, that is straying into the 1959-1969 period though, and I'd like to keep focused on the post-1969 period.

IMHO the Apollo Lunar decision ruined our best chance of getting a "better" space program which is why I keep drifting back to it. Once the historical forces are at the decision point there's little leeway and once past that point the organizational and programmatic changes involved have a significant moment all their own. But I'll try and cut it back

I've always been a big fan of the possibilities of the Saturn IB rocket.

It had that but was quickly overshadowed by its big brother and the program itself. It had a bit of shot during APP but frankly the moment was to keep what they could of the Saturn-V if they had any choice so it wasn't really an option.

Hmm. It required the SIVB? What I read is that the SIV was forced on Von Braun and his team by the USAF's efforts to stymie to rocket. So they were forced to develop an expensive new stage that they didn't need and had to replace in a few years anyway. The replacement SIVB, naturally was based off the design of the SIV. I strongly question if the upgraded second stage of the SIB would have been LH2/LOX fueled without the USAF's attempt at sabotage.

Not that I've seen really. Both Atlas and Titan, (kerolox) were considered but Titan even then was the more powerful vehicle so it was the default. In general there WAS no 'designed' upper stage for the Saturn at that point only notional ones based on either operational boosters (near term) or more powerful (hydrogen) upper stages at a later date. The main issue for the designers was they had no actual knowledge beyond open sources for hydrogen engines which pretty much meant Centaur and it alone wasn't going to be able to do the job. So an RL10 "upper stage" was assumed with a Centaur on top that. I'm pretty sure Rocketdyne was hinting at the J2 but it was in fact an Air Force engine not an Army one and ARPA wasn't clear on what exactly they planned for the Saturn in the first place. (One of the reasons the Saturn originally had the E1 engine was it was an 'open' ARPA project whereas the F1 was strictly Air Force. The need to have 'something' in the works NOW due to the Sputnik panic pushed a downgrade to the H1s and the E1 was dropped. "Wishes-and-fishes" but someone pointing out the LR87H work would have been nice but I'm not sure it was actually tested by that point)

As it was ARPA kept switching funding for the Saturn off and on due to Air Force pressure, (never mind the Commies we know who the REAL enemy is here right? ) as they kept "suggesting" they could do better with either SLS-1960 or Arcturus neither of which had any actual design work done beyond some art work but having the ear of one of the heads of ARPA was better than an actual design anyway In the end having "something" they could actually show the public became more important what was 'better' down the road so ARPA actually supported Saturn and the Air Force shelved their plans. And then NASA came along...

This looks wrong. Aluminium has a higher strength/weight ratio than steel. Or at least, this is true when comparing similarly priced equal weights of steel and aluminium alloy. Given that you are talking about steels for the SR-17 and X-15, I wouldn't be surprised if they were using some seriously fancy, expensive stuff.

The reason they used aluminum is because that's what the equipment, (originally Jupiter and Redstone) was designed to handle, switching to steel would have required a rebuild. As much as "clusters-last-stand" was derided and dismissed it was a very robust booster due to that fact and why they didn't think it would be an issue to recover. They'd done tests with the Redstone and the Jupiter was tougher and with the spider-beam and thrust structure of the Saturn it was all tougher yet. They were actually surprised at how little needed to be done to fit SRBs to the Saturn-1 once they looked into it. IIRC they turned the stage sideways and tumbled it to ensure it broke up on reentry because they were pretty sure if they didn't it would come down mostly intact without an actual reentry system.

By me, yes. Or at least, that's what I reckon is needed for a good space program that could realistically expect to be funded in the 20th Century. One could construct a moon ship in around 3-5 launches of such a rocket, launch larger space station modules, useful mini-shuttles and interestingly sized probes and scientific satellites without breaking the bank.

Once doing anything beyond robotic exploration of the bodies beyond Lunar orbit, manned flybys of Mars and Venus or building serious infrastructure in Earth orbit (like SPS satellites and BIG space stations), Energia and Saturn V class rockets start looking awfully good.

I'm with Workable Goblin on this one if you don't have Saturn-V/Energia already it doesn't in fact make sense to go for large payloads over cost-effective access. One of the reasons I keep suggesting actually starting recovery/reuse as planned initially for the Saturn because simply put it gives a logical baseline to use to compare later planning and a base to build on which we have lacked OTL. The Shuttle was not a mistake but a step to far with too little prior data/art to draw on.

Randy

 

[RanulfC]

I admire both Atlas and Saturn, the first appears to be an elegant exercise in using less for more while Saturn may be a "kludge" but it achieved more with less. In my thoughts these two would likely have been the foundations for military and civilian space launches where the USAF and NASA stay divorced. Without the Apollo push we know I think Saturn V may never be built and a more modest yet hopefully less spasmodic program would see Saturn I/IB and its evolution serve US well. Now in my imaginations for a rather different ATL I use the two (Atlas/Titan vs Redstone/Saturn) conceptually (not so much the as built hardware) to ponder how a German (not Nazi) versus American program might have evolved (I assume the USSR runs about the same). Atlas is grounded in American technology and method just as Saturn shows the influence of Von Braun and its "German" heritage. Saturn shows how a limited budget might force the development to build on what you had just as the A4 formed the basis for the later thoughts on getting bigger. My assumption is that the USA can always out spend, the USSR has more resources but only just and any other "Great Power" is some fraction of the American effort so economy is king if you want to run or win. So I get a three-way (four if the Anglo-French pursue a program too) space race. It makes it fun looking at the paper proposals that might get ground where more programs are competing. So thank you for indulging the queries on Saturn.

Actually the Atlas was going to be replaced by the Titan for the reasons of payload anyway as it did OTL. Atlas-Centaur and SRBs not withstanding it was peaking pretty fast and Titan had been designed from the start as a 'heavy' lifter in comparison. Funny thing about the Atlas and Von Braun is he never actually questioned the general concept of the 'balloon' tank, just its applications for booster work. Whereas Saturn showed how to 'make-do' with what you have on-hand in fact Titan was closer to a development of the A4 in that it was an internal structure, staged design which is what the A+ missiles were moving towards anyway. While the Atlas balloon tank design could be made bigger, (indeed the original Atlas design was a nice monster) it was inherently limited which was realized at the time. (Even as the "flyback" Atlas was being pitched to the Air Force Convair was studying adding internal structure as the payload margins of the Atlas grew)

If one were to supposed a "three-way" set up a "large" Atlas would be the initial US offering, while the USSR would probably still have an R7 analog and Germany an evolved A4 derived design similar to a Titan-1. Or course I've noted elsewhere that without Von Braun the US is likely caught even MORE off-guard by Soviet missile technology not due to Von Braun's engineering skills but by his managing to popularize space travel as "native" space advocates had failed to do. He managed to use his charisma in the right places so that space travel went from being derided as "Buck Rodgers Science Fiction Fantasy" to plausible in under an generation. One could wish he hadn't been tainted by association with the Nazis but frankly his talents would have been wasted anywhere else and the Nazis were desperate enough to take the chance the rest of the world wouldn't.

Randy

 

[RanulfC]

The FY '62 budget would have begun July 1st, 1961 (before 1976, the FY began on the first of July and ended on June 30th) so...maybe, given that Kennedy announced Apollo on May 25th. On the other hand, there really would have been little concrete idea of what the lunar program actually entailed by July 1st (never mind whenever the budget was actually passed), so I doubt it actually was a major factor in FY '62. FY '63 and beyond, yeah, but not FY '62.

My assumption with the budget was that, as I said earlier, it would crest at or a little higher than the historical upper limit on post-Apollo budgets (roughly $20 billion in inflation-adjusted funds) in the mid-'60s, then gradually decrease to '70s levels between then and the mid '70s, then more or less continue as usual. I figured thanks to the residual race mentality there would still be some pressure to pour money into the space program--just not nearly as much as OTL.

One reason i was wondering is that a lot of the supplement money wasn't for actual technology work but facilities and staffing such as building up Houston which may or may not apply to a less intense space race. You can argue that paying off Johnson, (which is what the Manned Spaceflight Center pretty much was) might not be a priority in such a case and the money might go to other areas. (It was a choice between that or an electronics center initially and they choose both but didn't put near as much money into the electronics center soon shut it down)

"Extraordinary effort" was meant to refer to justifying how NASA could afford to do whatever program the author i wants. Doing so would not really be required for a flyback kerolox stage given OTL events.

I'd argue that it might not be that straight forward as flyback had not yet become synonymous with 'reusable' at the time but one of many options. While it may not turn out to be AS effective as flyback they had a plan in place for ocean recovery and it would be less development time and cost to justify to Congress. (Specifically they wanted the booster back initially to see how it withstood flight and what if anything needed changing incrementally)

Trouble is that the Dyna-Soar program is still probably going to be canceled due to the lack of military utility, and there doesn't seem to have been much interest in reviving the design for Shuttle IOTL. There was, on the other hand, considerable interest in using the lifting-body shapes to build a mini-shuttle of some kind or another. So HL-10-based mini-shuttle seems much more likely to me than a Dyna-Soar-based equivalent.

Probably but in the interests of saving money and alt-NASA might consider picking the program up since at the time it was more advanced than a lot of the lifting bodies. On the other hand the lifting body programs may or may not be as starved for money as they were OTL either so it may be a wash.

I was certainly assuming the former, not the latter. That, at least, was a subject they were realistic on as they began to learn more about spaceflight.

Oddly enough that wasn't all that clear at the time as the design and testing process was a bit scattershot and was simply set aside due to the overwhelming pressure of Apollo. (And partially because as the payload size increased so to did the amount of studies on space stations to USE that payload! If one looks at the trend of the 'self-deploying' stations you may note that while the 'baseline' designs mostly show what looks like a Saturn-1 booster they are actually sized for Saturn-Vs... Or larger! Ya, Marshall wasn't the only group to get a bit carried away at times )

Randy

 

[Workable Goblin]

One reason i was wondering is that a lot of the supplement money wasn't for actual technology work but facilities and staffing such as building up Houston which may or may not apply to a less intense space race. You can argue that paying off Johnson, (which is what the Manned Spaceflight Center pretty much was) might not be a priority in such a case and the money might go to other areas. (It was a choice between that or an electronics center initially and they choose both but didn't put near as much money into the electronics center soon shut it down)

I am really tired of trotting out the actual process for site selection for MSC, so I'm not going to bother this time. All I'm going to say is that it was the Air Force, not NASA, that ultimately determined Johnson would be built in Houston, not Florida.

Leaving that aside, the need for those centers was being determined in parallel to and somewhat independently of the Apollo program, so I would assume that MSC, at least, is created to get the STG out of Langley and give it better facilities.

I'd argue that it might not be that straight forward as flyback had not yet become synonymous with 'reusable' at the time but one of many options. While it may not turn out to be AS effective as flyback they had a plan in place for ocean recovery and it would be less development time and cost to justify to Congress. (Specifically they wanted the booster back initially to see how it withstood flight and what if anything needed changing incrementally)

I mean in terms of "I don't need to figure out how to make Congress give NASA $$$$$, I just need to justify them putting the money they do have into this rather than that". You can see how "persuade Congress to spend the same amount of money differently" is a much easier row to hoe than "persuade Congress to spend lots of extra money," I hope?

And I would dispute that characterization of flyback not being synonymous with reusable, even leaving aside the influences of Apollo. Practically all proposals for reusable spacecraft from 1950 on--not just the von Braun rockets, but things like BoMi, RoBo, Aerospaceplane, and so on--were intended to be flyback or otherwise airplane-like vehicles. There really were not that many proposals for reusing vehicles by parachuting them back into the ocean, and I can't read those as anything other than experiments intended to prove the concept, or at most a compromise with available budgets and scheduling rather than as what anyone actually wanted to do.

Probably but in the interests of saving money and alt-NASA might consider picking the program up since at the time it was more advanced than a lot of the lifting bodies. On the other hand the lifting body programs may or may not be as starved for money as they were OTL either so it may be a wash.

On the gripping hand, Dryden was extremely efficient with money. Not to mention that they do have a limited budget and Dyna-Soar is going to be expensive while they're still working on Apollo...

Oddly enough that wasn't all that clear at the time as the design and testing process was a bit scattershot and was simply set aside due to the overwhelming pressure of Apollo.

Sure, but it's not like they're going to pick the first station design they have and run with it.

 

[Workable Goblin]

In any event, getting back to the actual title of the thread, there were really only four options for an alternate shuttle from OTL (leaving aside changes in details but not the broader outline, e.g. substituting pressure-fed for solid rocket boosters):

• Bigger shuttle
• Smaller shuttle
• Mini-shuttle
• Inverted shuttle

"Bigger shuttle" means the Phase B-type fully reusable vehicles, "smaller shuttle" means OMB-type vehicles resembling our shuttle but with smaller payload bays and payload capacities, "mini-shuttle" means a non-payload-carrying vehicle boosted by an expendable rocket like the HL-20, and "inverted shuttle" means developing a reusable booster instead of a reusable orbiter, i.e. the Right Side Up option.

In terms of plausibility, bigger shuttle is fundamentally unlikely, at best. The OMB correctly pointed out that it simply did not make sense to develop at any reasonable extrapolation of space traffic. Nowadays it might be financially feasible, but not in the 1970s. Combine that with a Congress and Administration that wanted to crack down hard on NASA's budget and it's hard to see any reasonable path towards NASA developing a fully reusable vehicle.

Smaller shuttle, on the other hand, has a pretty high chance of going through, for something that didn't happen. Just give the OMB a bit more political power, and they can probably force NASA to accept some kind of smaller shuttle. The effects of this would be interesting...obviously, it would be harder to sell shuttle as the "do-everything" vehicle if it were smaller, but I bet NASA would still try to get as many payloads as possible on board, and to be honest the vast majority of payloads launched by shuttle IOTL would also fit in a smaller vehicle. Smaller shuttle would still have a lot of the problems of our shuttle, but it would probably be cheaper to operate (if not necessarily by very much), so it might open up room for working on non-shuttle vehicles, especially since it would more obviously be a temporary waypoint. Shuttle II or something like that might actually be developed ITTL, though still probably not due to budget limitations. Development may or may not take less time than IOTL depending on how things work out; the major pacing items of the tiles and the SSME are still likely to be problems here, after all, despite the smaller size of the vehicle.

Mini-shuttle has similar effects, but even more so. After all, unlike smaller shuttle mini-shuttle clearly has no utility as a launch vehicle, so it's going to be limited to conducting a few orbital missions per year. This is also something that's fairly plausible, and perhaps likely in a timeline where NASA goes for a space station program to replace expensive Apollos while still moving towards the dream of a shuttle. Certainly to be very useful a vehicle of this type needs a station to go to, so some of the early/man-tended station proposals from Marshall might get somewhere in this timeline, things like the Power Module and so on. Given the complete absence of Shuttle, refinement of existing launchers like Titan, Atlas, and Saturn IB is going to continue. Supposing that the satellite market continues to grow, there will probably be a desire to replace these legacy launchers by the late 1980s, so it's pretty likely some kind of EELV or RLV program, probably (at least nominally) a joint USAF-NASA program, will pop around then or in the 1990s.

Inverted shuttle...well, read Right Side Up for that. I will add that it's also possible that they develop the hydrolox booster proposed for Phase B instead of modifying Saturn V as part of a phased program, where the simpler (in some ways) booster allows for the development of some of the technology needed for the full Phase B system, which can then be augmented with a reusable upper stage/orbiter later on. However, I suspect that this would end up mostly being a difference of flavor as opposed to creating a significantly different world than Right Side Up, though it might also be...educational. I think David Portree discussed a proposal along those lines somewhere...however, I think this option is also unlikely. Not, perhaps, quite as unlikely as the full Phase B/reusable orbiters, but for whatever reason NASA fixated on the reusable orbiter instead of the booster as what it wanted if it could have only one or the other, so you have to do some pretty good work in justifying why they would go the opposite direction from reality.

 

[fasquardon]

Which brings us to the "INT" or Intermediate (also "Interim" as in in-between) booster concepts which essentially tried to cherry-pick keeping parts of the Saturn-V going. Yes it's quite possible the INT-19 could have been ocean recovered if the thinking had been there but it wasn't. Essentially the INT vehicles were considered expendables with "mass-production" and "cheap" components making up for not being recoverable like the "shuttle" would be. They would 'supplement' the "shuttle" not compete with it. But that ran into the rather obvious economics issues and since 'reusable' equaled cost effective any requirement for a non-reusable LV rapidly dissipated. Goodbye Apollo/Saturn legacy...

I had wondered what the INT stood for.

So there was never any serious interest in pushing for other Saturn V hardware part of a fully or partially reusable system other than Boeing's pushing the fly-back Saturn 1C stage and using the J-2S as the shuttle's engine?

The Silverstein Committee that decided that developing the conventional upper stages for Saturn was a waste of time and money met in late 1959, when the transfer of Marshall to NASA was a foregone conclusion, so I don't see what the Air Force had to do with the decision (yes, analysis of hydrolox stages had begun earlier under the Air Force, but the actual decision to develop them wasn't made until then). Not to mention that the Committee quite conclusively demonstrated that hydrolox stages had massively superior performance to any kerolox stage. They persuaded von Braun of the merits of hydrolox, so it was at least a willing submission.

Not that I've seen really. Both Atlas and Titan, (kerolox) were considered but Titan even then was the more powerful vehicle so it was the default. In general there WAS no 'designed' upper stage for the Saturn at that point only notional ones based on either operational boosters (near term) or more powerful (hydrogen) upper stages at a later date. The main issue for the designers was they had no actual knowledge beyond open sources for hydrogen engines which pretty much meant Centaur and it alone wasn't going to be able to do the job. So an RL10 "upper stage" was assumed with a Centaur on top that. I'm pretty sure Rocketdyne was hinting at the J2 but it was in fact an Air Force engine not an Army one and ARPA wasn't clear on what exactly they planned for the Saturn in the first place. (One of the reasons the Saturn originally had the E1 engine was it was an 'open' ARPA project whereas the F1 was strictly Air Force. The need to have 'something' in the works NOW due to the Sputnik panic pushed a downgrade to the H1s and the E1 was dropped. "Wishes-and-fishes" but someone pointing out the LR87H work would have been nice but I'm not sure it was actually tested by that point)

I am going off of the Astronautix quote of Gen. Medaris' biography here: http://www.astronautix.com/s/saturna-1.html

We had gone through the whole process of selecting upper stages and had made our recommendations to ARPA. We had indicated very clearly that we were willing to accept either the Atlas or Titan as the basis for building the second stage. The real difference was that in one case we would be using the Atlas engines and associated equipment, built by North American, while in the other case, we would be using the Titan power plant built by Aerojet. Largely because of the multitude of different projects that had been saddled on the Atlas, we favor the Titan. Convair builds the Atlas, and we had great confidence in Convair's engineering, but this was over shadowed in our mind by the practical difficulties of getting enough Atlas hardware. However, we assured ARPA that we would take either one.

The time scale was important. In order to get an operational vehicle in the air as soon as possible, and be able to match and possibly exceed Russia's capabilities, we recommended that the first flying vehicle to be made up of Saturn as the first stage and a second stage built with a Titan power plant. We also recommended using the tooling available at Martin for the airframe. We felt that by the time we got through the second-stage tests, the powerful new Centaur oxygen-hydrogen engine would be in good enough shape to become the third stage. We then calculated that a, year afterwards, or perhaps a little later, could begin to come up with a second-generation satellite vehicle that would cluster the Centaur engine for second stage.

Our people made extensive presentations to ARPA and NASA during the late spring of 1959, always taking the position that we could work with either combination that was agreed to by both. We were anxious to have them agree, because it seemed obvious to us that the nation could not afford more than one very large booster project. We believed that the resulting vehicle would be enormously useful both to the Defense Department for advanced defense requirements, and NASA for its scientific and civilian exploration of space.

We finally got a decision. - - We were told that we could begin designing the complete vehicle along the lines that we had recommended, namely, with the Titan as the basis for the second stage. So far there was no sign of trouble. Remembering the difficulties that we had had in connection with our requirements for North American engines for Jupiter, with the North American people largely under control of the Air Force, we knew that if we were to get on with the job properly we had to make our contract direct with Martin for the second stage work, and with the Convair/Pratt & Whitney group for the adaptation of Centaur to the third stage. We asked the Air Force for clearance to negotiate these matters with the companies concerned The Air Force (BMD) refused, and insisted that we let them handle all areas with the contractor. They used the old argument that they as a group could handle the responsibility much better, and that if they didn't handle it, there were bound to be priority problems connected with the military programs for Titan and others. We knew that the Air Force had no technical capacity of their own to put into this project, and that if we gave them the whole job, they would be forced to use the Ramo-Wooldridge organization, now known as the Space Technology Laboratories, as their contract agent to exercise technical supervision and co-ordination. While we knew and respected a few good men in STL, we felt we had ample cause to lack confidence in the organization as such. As a matter of fact, when the House Committee on Government Operations looked askance at STL with respect to their position as a profit-making organization, some of the best men had left the organization. We threw this one out on the table and said that we would not, under any circumstances, tolerate the interference of STL in this project. We knew that we had all the technical capability that was needed to supervise the overall system, and could not stand the delays and arguments that would most assuredly result were that organization to be thrown in also. Both sides presented their arguments to ARPA...Mr. Roy Johnson ruled that we could go ahead and contract directly Martin and others as required. It is understandable that the Air Force took this decision with poor grace. It represented a major setback to the system of absolute control over their own contractors, no matter for whom those contractors happened to be doing work. It also left them pretty much on the side- lines with respect to major participation in or control over any portion of the Saturn as a space vehicle.

With the amount of money still available to us from fiscal year 1960 and with our authorization from ARPA, we proceeded immediately to negotiate engineering contracts with Martin. We thought that since Mr. Johnson had complete control over this program, we had gotten over the last important hurdle and could get on about our business. Little did we realize the hornet's nest that had been stirred up, and less did we realize that winning that battle was finally to mean that we would lose the war, and would lose von Braun's entire organization.

We had only a few weeks of peace and quiet. From events that occurred later, I think I can make a fair estimate of what happened during this short period. Having been overruled by Johnson, the Air Force took a new approach. They decided that in view of the importance and power that was given the Deputy Secretary of Defense for Research and Engineering by the 1958 changes in the defense organization, Dr. York represented their best avenue of approach through which to get back in the war.

For reasons of economy we had recommended, and it had been approved, that in building the second stage, we would use the same diameter as the Titan first stage -- 120 inches. The major costs of tooling for the fabrication of missile tanks and main structure is related to the diameter. Changes in length cost little or nothing in tooling. How the tanks are divided internally, or the structure reinforced inside, or the kind of structural detail that is used at the end in order to attach the structure to a big booster below, or to a different size stage above, have very little effect on tooling problems. However, a change in diameter sets up a major question of tools, costs, and time.

Suddenly, out of the blue came a directive to suspend work on the second stage, and a request for a whole new series of cost and time estimates, including consideration of increasing the second stage diameter to 160 inches. It appeared that Dr. York had entered the scene, and had pointed up the future requirements of Dynasoar as being incompatible with the 120-inch diameter. He had posed the question of whether it was possible for the Saturn to be so designed as to permit it to be the booster for that Air Force project.

We were shocked and stunned. This was no new problem, and we could find no reason why it should not have been considered, if necessary, during the time that the Department of Defense and NASA were debating the whole question of what kind of upper stages we should use. Nevertheless, we very speedily went about the job of estimating the project on the basis of accepting the 160-inch diameter. At the same time it was requested that we submit quotations for a complete operational program to boost the Dynasoar for a given number of flights. As usual, we were given two or three numbers, rather than one fixed quantity, and asked to estimate on each of them.

By this time, my nose was beginning to sniff a strange odor of "fish." I put my bird dogs to work to try to find out what was going on and with whom we had to compete. We discovered that the Air Force had proposed a wholly different and entirely new vehicle as the booster for Dynasoar, using a cluster of Titan engines and upgrading their performance to get the necessary first-stage thrust for take-off. This creature was variously christened the Super Titan, or the Titan C. No work had been done on this vehicle other than a hasty engineering outline. Yet the claim was made that the vehicle in a two-stage or three-stage configuration could be flown more quickly than the Saturn, on which we had already been working hard for many months. Dates and estimates were attached to that proposal which at best ignored many factors of costs, and at worst were strictly propaganda.

With the large diameter SIV stage, the Saturn 1 was able to boost 9 tonnes to LEO, by comparison, depending on the second stage chosen (whether a single Titan 1 derivative, a cluster of Juno rockets or an Atlas derivative), the original Saturn I designs (then the Juno V) would have launched between 6.5-12.5 tonnes. So while the Saturn IB may have needed the SIVB stage, the Saturn I would, I think, have been better without the SIV stage, since even a less capable design with a Titan 1 stage would have been cheaper per payload placed into orbit.

I think improving flight rates is still the better solution there. More exactly, if the program expands past routine orbital operations it would make more sense to replace a Saturn IB or IB+ rocket with a shuttle with similar capabilities but the ability to fly more often for less money than to develop a Saturn V or Energia. You have to go really huge to get much benefit from that size of rocket, and there's little real likelihood of that happening anytime particularly soon. (Needless to say, I think Elon would have been better off working on new Falcon-sized rockets than on BFR)

That was pretty much exactly my point. Saturn Vs and Energias are useful when doing really huge things, but for anything that we've done or seriously considered, the big rockets just don't pay off.

Unless you mean that a 30 tonne to LEO launcher is too big. In that case, well, for routine use, you'd be right. But being able to bolt together a larger and somewhat expensive rocket from routinely used LVs (like the Delta IV approach) is really useful for the sort of "expeditionary" activities in space we spent the 20th Century doing.

I'm with Workable Goblin on this one if you don't have Saturn-V/Energia already it doesn't in fact make sense to go for large payloads over cost-effective access. One of the reasons I keep suggesting actually starting recovery/reuse as planned initially for the Saturn because simply put it gives a logical baseline to use to compare later planning and a base to build on which we have lacked OTL. The Shuttle was not a mistake but a step to far with too little prior data/art to draw on.

I disagree on that. If anyone decides to build a SPS constellation or to colonize Mars, I expect the 100-170 tonne to LEO class of rockets will be the most economical option by a large enough margin that if they don't have such a rocket available, they will develop it.

But of course, building any kind of rocket doesn't pay off unless access is just that valuable or you have the launch rates to spread the development costs effectively.

fasquardon

 

[Workable Goblin]

With the large diameter SIV stage, the Saturn 1 was able to boost 9 tonnes to LEO, by comparison, depending on the second stage chosen (whether a single Titan 1 derivative, a cluster of Juno rockets or an Atlas derivative), the original Saturn I designs (then the Juno V) would have launched between 6.5-12.5 tonnes. So while the Saturn IB may have needed the SIVB stage, the Saturn I would, I think, have been better without the SIV stage, since even a less capable design with a Titan 1 stage would have been cheaper per payload placed into orbit.

If you read the quote carefully, you'll notice Medaris mentions "We then calculated that a, year afterwards, or perhaps a little later, could begin to come up with a second-generation satellite vehicle that would cluster the Centaur engine for second stage," or in other words they were actually planning on introducing something equivalent to the S-IV as a replacement for the Titan upper stage, they just weren't doing it first to get a rocket flying faster. Deciding not to develop the Titan-Saturn was merely a decision not to waste time and money on a rocket with no payloads that was going to quickly be replaced by a new design before they would really do anything with the rocket when they could start with the new design to begin with.

That was pretty much exactly my point. Saturn Vs and Energias are useful when doing really huge things, but for anything that we've done or seriously considered, the big rockets just don't pay off.

But those have to be really huge. Not just "send people to Mars" big, not even "colonize Mars" big, but "build multiple satellites the size of Manhattan" big (and even then you could always go the space-based resources route, and still not need 100 ton rockets). Especially since rockets, unlike other forms of transportation, are automated, so the costs don't scale as much with increasing flight rate as they do for, say, ships (ergo, giant oil tankers and container ships instead of great numbers of them).