Quote from: butters on 02/20/2011 09:34 pmHow central did the NASA consider the shuttle to be to the agency's post-Apollo future?Initially, not very. In the circa-1969 documents, the Space Shuttle is really only ever mentioned as an afterthought, with a ~7 tonne payload. The big push was to a post-Skylab "Space Base" with a reusable "Nuclear Shuttle" for ferrying stuff to/from GEO and lunar orbit (and as a basis for the Mars vehicle). Without DoD support for Shuttle, NASA may very well have followed a path closer to the Soviet's strategy of the era, with LEO space station(s) and capsules. One (of many) ways to do that would be to fly Skylab as was historically done, but with a fourth mission that reboosts it in 1977-78. Then, in the 1980s, modules are added Mir-style (launched on Saturn IC/Fs). So, by the end of the Cold War, the US has a large (6-person) but aging space station serviced by capsules. In other words, precisely the situation that we'll have in four years' time.
How central did the NASA consider the shuttle to be to the agency's post-Apollo future?
1x J-2 on 1x F-1 would have been an excellent TSTO. Of course you'd want a monolithic 6.6m tankset on the first stage.Quote from: simonbp on 02/20/2011 06:45 pmBut for either of these concepts to have flown, it would have required NASA deciding to make its post-Apollo direction be in large space stations, not Shuttle.I'm still confused about this part NASA history even after watching the Dale Myers presentation on MIT OpenCourseware. I know that George Mueller and Tom Paine wanted a large space station in LEO as the next step toward Mars, I know that he'd hoped the post-Apollo budget would leave room for both a large space station launched on Saturn Vs and a reusable "space shuttle" for crew and provisions, and I get the sense that they were envisioning a considerably smaller shuttle than the DoD requested.But in alternative history mode: once Myers comes in and the budget cuts come down and it becomes clear that they won't be able to afford a space station along with the DoD-spec shuttle even if they cancel Saturn V and launch the station on the shuttle, would it have been unthinkable for NASA to prioritize the station over the shuttle? After all, the station was the desired end, and the shuttle was just one arguably ambitious means to that end. If they'd scrapped the shuttle and pursued the station instead, the Saturn family would remain relevant, and I think that the DoD would have been happy to see the shuttle fall by the wayside.How central did the NASA consider the shuttle to be to the agency's post-Apollo future? Were they operating in the hope that the budget cuts were temporary and that they'd have more funding in the future to get their space station?
But for either of these concepts to have flown, it would have required NASA deciding to make its post-Apollo direction be in large space stations, not Shuttle.
Keep in mind F9 does achieve it's payload with a hydrocarbon upper stage.With a hydrogen upper stage it likely would be similar to Atlas V still smaller but over all it is a more flexible system due to the fact it is a modular LV.A modular vehicle like F9 can do both Titian IIs and the IB's jobs depending on its configuration.
As for growth potential the only way I can think of to really increase the IB's payload past something easily reached by F9-H or even existing EELV variants such as the Delta IV-H would be a complete redesign the first stage to use monolithic tanks.I'm not sure if SRBs or even multi cores were an option with the cluster tank.No provisions for attachment etc....
Delta 4 Heavy hasn't turned out to be as modular as one might think, due to differences required in the CBCs for Heavy versus Medium configurations.
the design decision to go with one mirrored booster.
Part of the reason that the original S-I stage was so heavy was that it had to support the huge bending loads that would have been imposed on it when launching the winged Dyna-Soar (I've never understood how the more slender Titan III-C was going to cope with those loads).
Quote from: edkyle99 on 02/21/2011 06:12 pmDelta 4 Heavy hasn't turned out to be as modular as one might think, due to differences required in the CBCs for Heavy versus Medium configurations. Of course, you realize that has nothing to do with the viability of the concept, but more to do with engine performance shortcomings and the design decision to go with one mirrored booster.
Are you suggesting the cost of Atlas would jump through the roof as well if the Heavy was fielded?
Quote from: ugordan on 02/21/2011 06:49 pmAre you suggesting the cost of Atlas would jump through the roof as well if the Heavy was fielded?*That* is a very good question! - Ed Kyle
Quote from: ugordan on 02/21/2011 06:49 pmAre you suggesting the cost of Atlas would jump through the roof as well if the Heavy was fielded?*That* is a very good question!
Quote from: edkyle99 on 02/21/2011 07:37 pmQuote from: ugordan on 02/21/2011 06:49 pmAre you suggesting the cost of Atlas would jump through the roof as well if the Heavy was fielded?*That* is a very good question! Why would it? The cores themselves, MLP, pad, and VIF are (supposedly) ready to go, except for (IIRC Jim has observed) adding the other tail service masts -- which hardly seems like a major engineering challenge. I ran across a quote from ULA that at least 95% of the hardware has already flown. In the absence of other information, would not one assume that the costs to bring the last elements from CDR to flight would be borne by the first customer ordering the minor variant, as for example happened with Atlas V 551 and New Horizons, no? What would the additional ongoing costs to keep the Heavy in service, borne (perhaps) by all A-V customers? -Alex
Atlas would not have to modified the cores for a heavy.
When Dyna-Soar was looking for a launch vehicle, Martin proposed something called "Titan C" (not "IIIC"). At the time Titan was only what we know today as "Titan I" (Martin did not get a contract for Titan II until 1960, a couple of years after the Titan versus Saturn consideration was underway). "Titan C" would have been a fat Titan powered by four Titan I LOX/RP engines, topped by a fat second stage powered by a pair of the same engines, with longer nozzles. See http://history.nasa.gov/SP-4404/ch12-3.htm for details.
I'm not sure if SRBs or even multi cores were an option with the cluster tank.No provisions for attachment etc.
Quote from: Jim on 02/21/2011 07:49 pmAtlas would not have to modified the cores for a heavy. Why does Atlas not have to modify its cores for the heavy version, whereas Delta does?
Isn't the nozzle of an F-1 wider than the tank on Redstone?!?