But, if you think keeping the Saturn 1B would have served better in the post Apollo years, then there might have been a strong case to develop the S-1F to replace the S-1B. Or I suppose you could have creatd the Saturn 1B "Heavy with 3 cores.
Quote from: Lobo on 06/05/2012 06:09 pmBut, if you think keeping the Saturn 1B would have served better in the post Apollo years, then there might have been a strong case to develop the S-1F to replace the S-1B. Or I suppose you could have creatd the Saturn 1B "Heavy with 3 cores. In my view, NASA didn't have money to develop anything new. It would have simply flown what it had: Saturn IB, which was an adequately capable launcher. The Agency would have tweaked the design as time passed, to cut costs and improve performance, but it would have retained everything that already worked, for years or decades. If I understand this hypothetical "S-1F" that you mention, it would have used F-1 engines. In order to cut costs, NASA would have dropped F-1 entirely (which it did). H-1 could be retained because it shared much in common with the Delta and Atlas engines, helping cut costs for all. Under this scenario, NASA would likely have sought to gradually improve H-1, which would have been an interesting path. - Ed Kyle
Everybody seems obsessed with the S-IB's multi-tank structure. It certainly wasn't optimal, but I'm have a hard time seeing how completely redesigning the stage would have been cost-effective. As I showed previously in this thread, the payload benefit of switching to a mono-tank S-IB would have been small. With the S-IB stage being cheaper than the S-IVB anyway, modest cost reductions of the S-IB wouldn't have had a big impact on vehicle costs anyway. Documents I've posted previously in this thread put the cost of the multi-tank stage about even with that of the S-IVB, assuming a substantial production rate of S-IVBs for both Saturn IBs and for Saturn Vs. In a scenario with just a few Saturn IBs and no Saturn Vs produced every year, the S-IVB surely would have been quite a bit more expensive than the S-IB.
Maybe a triple-core Saturn IB would have required sufficient redesign of the first stage as to make going to a mono-tank design sensible. Anyway, without cross-feed I get 43,700 kg to a 100-nautical-mile orbit due east from KSC for a three-core Saturn IB with a J-2S upper stage and SA-217 weight reductions. I removed four engines from the core S-IB to keep the thrust-to-weight ratio down to about where it was for the plain vanilla Saturn IB (doing so also increases the payload, by making the vehicle more like a three-stager). With cross-feed, the payload rises slightly to 45,100 kg (I'm wondering why the difference is so small). For comparison, the payload of the triple-core Saturn IB is in between the payloads with two or 4 UA-1207 SRMs strapped on (about 37,000 kg and 48,000 kg, respectively).Just for the fun of it, I attach a 1970 paper presented by Jack Swigert that briefly compares Shuttle- and Saturn-IB-boosted space-station programs.P.S. Streamlining the S-IB so that it has the same structural efficiency as the Atlas V (dry mass is 7.4% of propellant mass) boosts the payload capability of the triple-core Saturn IB with cross feed to 47,200 kg.
Quote from: Proponent on 06/06/2012 05:21 amMaybe a triple-core Saturn IB would have required sufficient redesign of the first stage as to make going to a mono-tank design sensible. Anyway, without cross-feed I get 43,700 kg to a 100-nautical-mile orbit due east from KSC for a three-core Saturn IB with a J-2S upper stage and SA-217 weight reductions. I removed four engines from the core S-IB to keep the thrust-to-weight ratio down to about where it was for the plain vanilla Saturn IB (doing so also increases the payload, by making the vehicle more like a three-stager). With cross-feed, the payload rises slightly to 45,100 kg (I'm wondering why the difference is so small). For comparison, the payload of the triple-core Saturn IB is in between the payloads with two or 4 UA-1207 SRMs strapped on (about 37,000 kg and 48,000 kg, respectively).Just for the fun of it, I attach a 1970 paper presented by Jack Swigert that briefly compares Shuttle- and Saturn-IB-boosted space-station programs.P.S. Streamlining the S-IB so that it has the same structural efficiency as the Atlas V (dry mass is 7.4% of propellant mass) boosts the payload capability of the triple-core Saturn IB with cross feed to 47,200 kg.Very interesting. Thanks for running the numbers.
Huh? They apparently had the money to develop a brand new bleeding edge Space Plane and integrated HLV to launch it, as well as major modifications to the mobile launchers, and pads. I would think an S-1F stage would have been a drop in the bucket compared to that development project.
Actually, I’m not obsessed with the mult-tank structure per se. But more thinking that they wouldn’t be building the Redstone and Jupiter tanks indefinitely. According to Wikipedia (for what it’s worth), Redstone’s were in service until 1964, and Jupiter was in service until 1961. As I understood, the S-IB stage was basically Chrysler using their production lines and stores of those tanks they made for Redstone and Jupiter. A pretty cost-effective solution really. You just make a new larger stage our of your existing products. But, once those rockets are not long in service with the military, then you are producing those tanks soley for the S-1B, does it become not as cost effective then? Maybe, maybe not, I don’t know. But I’d think it might make the cost metrics less appealing as it went on.
And maybe Chrysler (if they were to keep the contract) would like to develop a new tank a little more optimally suited if that role, rather than one that was sort of thrown together out of spare parts. Maybe with some upgrades to the H-1, some minor weight reductions of the monotank, and a little large tank volume, that could have boosted the Saturn 1B to a little better performance. Maybe around 25mt. If it was still going to be cheaper to keep rolling the Jupiter and Redstone tanks off the assembly lines, then so be it, it could have just stayed with that. But a competition could have been done after an original contract was given to Chrysler for X number of S-1B stages to keep NASA flying for several years. And that competition could have competed whatever Chrysler wanted to offer with an offering from Douglas, who could have offered an S-IVB stage derived mono-tank stage, using the same barrel and tank-caps. Might have been able to use the same LH2 tank, and just have a new RP-1 tank with no common bulkhead. And let the best supplier win. If Douglas won, they could still use a cluster of H-1’s, since those were Rocketdyne engines and not Chrysler owned hardware. Or maybe Chrysler would win if they could keep their production costs down with their Redstone and Jupiter tanks, since they wouldn’t need any new development funds. Or they may want to bid a new stage with a monotank? Would have been a good competition I think.
The most obvious improvement would be precisely what did happen when they improved the H-1's to go on Delta, we call the resulting engines the RS-27. An extra 5% in thrust, an extra 10s impulse....
Quote from: Downix on 06/07/2012 07:51 pmThe most obvious improvement would be precisely what did happen when they improved the H-1's to go on Delta, we call the resulting engines the RS-27. An extra 5% in thrust, an extra 10s impulse....Are you sure about that? The SA-217 paper I attached previously gives sea-level and vacuum thrusts of 205,000 lb and 229,000 lb, respectively, for the H-1, the sea-level specific impulse being 263.4 s. Judging by what's on astronautix.com (maybe you have better info), it looks like the RS-27 had a chamber pressure 1 bar higher, a thrust 800 lb higher, and a specific impulse a fraction of a second higher. The RS-27A looks like it was an RS-27 with a longer nozzle, giving lower sea-level performance and higher vacuum performance, but not to the tune of 5%.That's not to say that the H-1 couldn't have been improved to that degree, but I wasn't aware that it had been.
STS cost much more than expected to develop. NASA paid the money only because it had to pay.And the Agency had the money, in part, because it was not flying Saturns or Apollos for most of the 1970s. The scenario here is "what if ... never .... cancelled? If Saturn IB/Apollo had continued to fly, NASA would have been paying large annual sums simply to keep the program running. There would have been no money for a brand new Saturn stage development effort.
This got me to thinking, so I ran some more based on this. Adding the Titan-3M Centaur as a third stage, or as an EDS rather, it could easily push a good sized load into Lunar orbit, about 16 metric tons, enough for a cargo automated LEM using 1960's technology.
A heavily upgraded Atlas Centaur could have, for example, matched Soyuz capability to LEO.
Quote from: edkyle99 on 06/08/2012 12:23 amSTS cost much more than expected to develop. NASA paid the money only because it had to pay.And the Agency had the money, in part, because it was not flying Saturns or Apollos for most of the 1970s. The scenario here is "what if ... never .... cancelled? If Saturn IB/Apollo had continued to fly, NASA would have been paying large annual sums simply to keep the program running. There would have been no money for a brand new Saturn stage development effort.Um, yes it was. The last Apollo didn't fly until 1975, with ASTP. And unless you consider the four years 1976-1979 "most of the decade," then NASA was flying Saturn/Apollos during the majority of the 1970s, or at least needed to maintain a good chunk of the infrastructure to do so. There's no reason some kind of similar "fly out the old hardware, but don't bother making any more" couldn't apply here. This would lead to a gap probably starting sometime around when our gap was (since there were only two or three more Saturn IBs left, together with one Saturn V, at that time). Hopefully it would be shorter, though.Anyways, the big advantage to monoblock is that you can use an F-1A instead of the H-1 cluster. It would actually be cheaper (based on Downix's numbers, $4.8 million for the one F-1A versus $7.2 million for the eight RS-27s), and for a 3% increase in weight you get a 12% increase in thrust and some degree of improvement in specific impulse (I'm not sure how much, perhaps as much as 20 seconds vacuum). That should significantly improve your performance compared to the RS-27 cluster, especially if you stretch the monoblock stage to maintain the same thrust/weight ratio overall. If, say, you wanted to save the F-1 for later, this would be a great choice. OTOH, if improvements in the RS-27 could get the sea-level thrust up to about 225,000 lbf, boost vacuum and sea level ISP maybe 10 seconds, and reduce the costs to only $600,000 per, then the RS-27 cluster would be equivalent to an F-1A. But that does seem a bit riskier to bet on.Whatever hypothetical weight savings you get from going to a monoblock might also be used for recovery equipment, parachutes and so forth. Maybe you could sell it as gradually progressing up to the Shuttle--now we develop the big booster stage and prove our ability to recover it, next we'll design a reusable spaceplane for the upper stage. Might be tricky, but people did consider similar designs historically, so...Alternatively, since they're continuing with Saturn anyways, they might just skip any further Saturn IB missions (ie., Skylab, ASTP) until their new vehicle came around. I'm not saying this is likely, but then they considered cancelling all of the J-class missions IOTL, so clearly people were a little cancel-happy in the early decade. The more pertinent problem would be designing a new block of Apollos that would be better optimized for the new low Earth orbit/space station role than the Block II, this could very well derail any attempt at developing a S-IF. That would be nice, maybe, "Block III" is required.
Quote from: DownixThis got me to thinking, so I ran some more based on this. Adding the Titan-3M Centaur as a third stage, or as an EDS rather, it could easily push a good sized load into Lunar orbit, about 16 metric tons, enough for a cargo automated LEM using 1960's technology. Ah, Saturn-Centaur. It was supposed to go on the IB originally, not the Titan...
Quote from: DownixA heavily upgraded Atlas Centaur could have, for example, matched Soyuz capability to LEO.Soyuz, though, was a little undersized--not much, but it definitely wasn't close to Saturn IB/Apollo in most aspects (the famous difference in pressurized volume aside). In the 1970s, at least, it had some definite maximum altitude limits, for example, that controlled some of how ASTP was planned.
Quote from: edkyle99 on 06/08/2012 12:23 amAnd the Agency had the money, in part, because it was not flying Saturns or Apollos for most of the 1970s. The scenario here is "what if ... never .... cancelled? If Saturn IB/Apollo had continued to fly, NASA would have been paying large annual sums simply to keep the program running. There would have been no money for a brand new Saturn stage development effort.Um, yes it was. The last Apollo didn't fly until 1975, with ASTP. And unless you consider the four years 1976-1979 "most of the decade," then NASA was flying Saturn/Apollos during the majority of the 1970s, or at least needed to maintain a good chunk of the infrastructure to do so.
And the Agency had the money, in part, because it was not flying Saturns or Apollos for most of the 1970s. The scenario here is "what if ... never .... cancelled? If Saturn IB/Apollo had continued to fly, NASA would have been paying large annual sums simply to keep the program running. There would have been no money for a brand new Saturn stage development effort.
The Saturn IB used for that 1975 ASTP mission was manufactured in 1967. The Agency was not funding new Saturn or Apollo construction during the 1970s, except for the final bits and pieces of production closeout at the beginning of the decade. The "never cancelled" scenario assumes constant production of rockets and spacecraft beyond that authorized in 1968, when new production funding was stopped. - Ed Kyle
Hence, by the time any of the cost estimates appearing in this thread were produced, the Saturn program must already have been bearing the full cost of the 70-inch and 105-inch tank tooling.
Building a mono-tank first stage would not be just a matter of stretching an S-IVB, moving the bulkheads and attaching eight engines instead of one. The loads would be different and it would be a new stage, which would have to be designed and tested. (Just look at SLS. Even ignoring the money being spent to upgrade the SRBs to five segments, it's going to cost over $10 billion to re-arrange the Shuttle's engines and tanks into SLS block 1). On top of that, as the attachments to previous posts show, the S-IVB cost more than the S-IB, despite having many fewer engines. That suggests it would not have been a great starting point for a new low-cost first stage. Weight is critical on an upper stage, and the cost of the S-IVB reflects that. Design objectives for a lower stage are different.
Quote from: Lobo on 06/07/2012 11:11 pmHuh? They apparently had the money to develop a brand new bleeding edge Space Plane and integrated HLV to launch it, as well as major modifications to the mobile launchers, and pads. I would think an S-1F stage would have been a drop in the bucket compared to that development project.STS cost much more than expected to develop. NASA paid the money only because it had to pay.And the Agency had the money, in part, because it was not flying Saturns or Apollos for most of the 1970s. The scenario here is "what if ... never .... cancelled? If Saturn IB/Apollo had continued to fly, NASA would have been paying large annual sums simply to keep the program running. There would have been no money for a brand new Saturn stage development effort.There was no money for anything during the 1970s. Saturn/Apollo ended. The SST cancelled. It was the post-Vietnam U.S. austerity decade. Gerald Ford, Jimmy Carter, hyper-inflation, gas lines, the start of the rust belt, and so forth. We are on the cusp of a repeat of that era in our own time, though not necessarily with the same effect on NASA. - Ed Kyle
Quote from: edkyle99 on 06/08/2012 12:23 amQuote from: Lobo on 06/07/2012 11:11 pmHuh? They apparently had the money to develop a brand new bleeding edge Space Plane and integrated HLV to launch it, as well as major modifications to the mobile launchers, and pads. I would think an S-1F stage would have been a drop in the bucket compared to that development project.STS cost much more than expected to develop. NASA paid the money only because it had to pay.And the Agency had the money, in part, because it was not flying Saturns or Apollos for most of the 1970s. The scenario here is "what if ... never .... cancelled? If Saturn IB/Apollo had continued to fly, NASA would have been paying large annual sums simply to keep the program running. There would have been no money for a brand new Saturn stage development effort.There was no money for anything during the 1970s. Saturn/Apollo ended. The SST cancelled. It was the post-Vietnam U.S. austerity decade. Gerald Ford, Jimmy Carter, hyper-inflation, gas lines, the start of the rust belt, and so forth. We are on the cusp of a repeat of that era in our own time, though not necessarily with the same effect on NASA. - Ed KyleI understand that, but the same could have been said for any continuing space station program using Apollo components. Costs may have went up more than expected, and NASA would have paid the money only because it had to. And that’s discounting the inevitable cost saving measures that would have likely taken place when transitioning from the hardware that was taking Apollo to the moon, to the “standard” hardware that was the PoR going forward. Once there were contracts and a new PoR established, than the contractors could make investments to bring down costs and raise quality and reliability. Once they knew they’d be making more than just the original X number of components for missions through Apollo 20. All of the hardware was made under two criteria that would have changed post Apollo. 1) Money was no object (not much of an object), 2) we had to hurry to beat the Soviets and get it done by the end of the decade. And what I imagine that lead to, is a lot of 1-off tools and components, and a lot of over design because streamlining and efficiency took a back seat to speed. So don’t take too long to see how much weight you can trim off, or how you might be able to consolidate parts, or tools, or production lines. Just increase the margin and safety factor and get it built!Once those two conditions didn’t exist any more, then there could have been a more involved process on how to shave weight and cost off the hardware, as well as retiring some hardware that wasn’t necessary for the new space station centric PoR. So again, as the title of the thread says, what if Saturn/Apollo hadn’t been cancelled. That assumes that the lunar program WAS cancelled, but that the decision was made to optimize existing development, infrastructure, and hardware for a post Apollo PoR. So, I’m not sure when the last Apollo CSM or Saturn V was actually built, if it was before Apollo 11, then once Apollo 11 had been finished and we made it to the Moon, and it was a done deal the lunar program would be terminated, then would have been the time to be evaluating contracts and figuring out what was going to be kept and what was going to be retired, while NASA was flying out the existing hardware. Maybe it would be decided to only keep S-1B, S-IVB, and Apollo CSM, and to start working on a space station architecture, which could have started with Skylab as a test bed, just like we actually did, and then take the lessons learned and incorporated them into some sort of Skylab 2. Although they probably couldn’t have used the S-IVB as a hull again, since Skylab massed 75mt and even a Saturn 1B Heavy couldn’t get it to LEO. If S-IC and S-II were retired, they would have been limited to modules of the mass of what a Saturn 1B or Saturn 1B-heavy could loft. But that’s ok, Skylab was sort of a way to reused Apollo leftovers that were already built and paid for. After that, a “Skylab 2” would have likely been a more purpose-built station like the ISS. With 20mt modules being put in place by Saturn 1B, or 45-50mt modules being put in place by Saturn 1B heavy. Crew rotations by Saturn 1B and the Apollo CM with a new cargo trunk instead of the SM so several mt of supplies could go up with each crew rotation. (I picture something like the SM shell with it’s RCS system, but without the SMME and all of it’s fuel tanks. The RCS tanks and other ECLSS would be consolidated into the front of it, leaving new room in the back for cargo racks. S-IVB would put it in LEO, so the SM wouldn’t need to do any cric burn. Similar to Dragon) Or something.Anyway, the point being the changed could have been done incrementally, starting after Apollo 11, and continuing until after Apollo 17, where things could have shifted gears in earnest to start developing a permanent space station, but using Skylab as the test bed that it was to gain information that would have been integrated into the design of the new station. And Skylab itself probably could have been extended if STS hadn’t been in the works and sucking up all the budget, and the S-1B or S-1F and S-IVB stages, as well as new Apollo CM’s would still be in production and available for more crews and resupply missions. While that was going on, the new space station could be under development and designed to use the existing LV. Centaur could be added if a new lunar program was approved down the road, as Downix said.
Of they could have gone wet-lab and still launched it on S-IV for additional modules off of Skylab.
