Saturn Shuttle gets the go-ahead rather than OTL design

If Saturn Shuttle gets the go-ahead rather than the OTL design, there would be no equivalent of the Challenger and Columbia disasters but what other changes if any could be expected?
 

Thande

Donor
If Saturn Shuttle gets the go-ahead rather than the OTL design, there would be no equivalent of the Challenger and Columbia disasters but what other changes if any could be expected?

Presumably there would be a political impact due to the whole thing about the SRBs being manufactured in Utah, for a start.

I wonder if there would be a move to eventually make the Saturn V first stage engines and Space Shuttle main engines interchangeable?
 
If Saturn Shuttle gets the go-ahead rather than the OTL design, there would be no equivalent of the Challenger and Columbia disasters but what other changes if any could be expected?
The Columbia failure mode would still exist, and is actually quite a probable one.

With the Saturn Shuttle, the bare pad concept remains viable - it was the weight of the SRBs that forced the umbilical tower off the MLP. That gains some things and loses others, but is probably a net positive.

There will probably be problems with the VAB, since I don't think the full wingspan of the Shuttle would fit through the upper part of the doors. This could be expensive to resolve.

SLC-6 would be much easier to design - no hydrogen accumulation in the flame trench - but would have to be a bigger facility and require the ability to handle S-IC stages. That would entail lots more civil engineering, but of a conventional form.

The SSME would be designed for air starting at altitude, so could have a higher expansion ratio and lower thrust. It would actually be feasible to run a Spiral 1 shuttle with J-2S motors whilst the SSME is developed for Spiral 2.

NASA has a more obvious path to an inline HLV if and when the time comes; it's a matter of designing and integrating a new upper stage for the Saturn IC, rather than massively reengineering the entire system.
 
I wonder if there would be a move to eventually make the Saturn V first stage engines and Space Shuttle main engines interchangeable?
That'd be unlikely--the F-1 used kerosene/LOX, while the Shuttle was always going to use hydrogen. Redesign S-IC to use hydrogen, and its a totally different stage, and a kero/LOX Orbiter/ET pair seems...unlikely, for a variety of cultural and technical reasons.

However, it's possible that with a serial-staged Saturn-Shuttle and thus no requirement for high thrust from the Shuttle engines down in the soup of sea level atmosphere, they can stick with J-2S or another gas-generator engine instead of needing the full-flow staged-combustion of OTL SSME. That'd dramatically reduce the design challenges for the engine's turbomachinery, and keep the engine more reusable, compared to the OTl one which ended up needing to be removed and torn down between every flight for inspections.

There will probably be problems with the VAB, since I don't think the full wingspan of the Shuttle would fit through the upper part of the doors. This could be expensive to resolve.
One possibility might be to rotate the orbiter on the stack--hang it so that the left wing comes out the door before the right wing, instead of belly first. It'd still be a serious design constrain for sure.
 
One possibility might be to rotate the orbiter on the stack--hang it so that the left wing comes out the door before the right wing, instead of belly first. It'd still be a serious design constrain for sure.
I thought of that possibility, but I think you'd still have issues with the tail fin height. Probably more manageable (twin fins perhaps?) but a definite challenge.
 
There will probably be problems with the VAB, since I don't think the full wingspan of the Shuttle would fit through the upper part of the doors. This could be expensive to resolve.

One possibility might be to rotate the orbiter on the stack--hang it so that the left wing comes out the door before the right wing, instead of belly first. It'd still be a serious design constrain for sure.

Does the Shuttle even have the same wingspan? If this PoD goes as far back as before the discontinuing of the Saturn V, then the Shuttle may have a very different design, perhaps without such huge wings.

Here's a sketch of a proposed serial design (orbiter design obviously crude):

orbsic1-660x799.gif


That would mean the orbiter engine in such a design doing the rough equivalent of the S-II (part that falls off second), perhaps a bit less. 4 or 5 J-2s would do the job, even if only to minimize the number of engines in production.
 

Archibald

Banned
No SRB mean Challenger disaster can't happens. Still a disaster will happen sooner or later if NASA persists trying to ram 24 shuttle flights into a single year.
Even in Saturn mode, the shuttle won't lacks lethal flaws in its design. Boom goes the SSME is an example. Crack the heatshield is another. There are hundreds of possible failure modes hidden in the shuttle.

For example: the SSME are fed from the tank, and the pipping has to go through the heatshield. When the shuttle drops the tank, it needs to fill the holes left by the tank plumbing. Thus there are folding doors that close the heatshield. If for a reason or another one of the door doesn't close, you have a certain STS-107 burn through.

The issue was that the S-IC was not reusable - it couldn't really be dunked into the sea for reuse
(yes, I know, there were studies where they blowed the top of the oxygen tank so that air got trapped inside, making the S-IC floats upside down, with the pack of F-1s safely bobbing out of the water - NASA doesn't seem to have been interested. There was also the matter of flight rates - reusing a standard S-IC made sense only at low flight rates)

The S-IC two options were either a) expendable or b) manned-winged. There was no in-between.

Late September 1971 NASA administrator James Fletcher send his budget request to the Office of Management and Budget. He proposed a Plan A and a Plan B.

Plan A was the Saturn shuttle with the manned/winged S-IC.
Plan B was a big dumb pressure-fed booster, unpiloted, unwinged, that could be recovered at sea.

OMB picked up Plan B, but later changed their mind. See my new space TL for what happened next :D

Presumably there would be a political impact due to the whole thing about the SRBs being manufactured in Utah, for a start.
I did a little research on this the other day. NASA twice administrator (1971 - 1977, 1986 - 1988) James C. Fletcher was a Mormon and director of the university there.
After the Challenger disaster there was a senator that accused Fletcher of favouring Morton Thiockol back in '72, a company with headquarters set in ... Utah.
The name of the Senator was Al Gore, Jr.
The inquiry led to nothing - Fletcher was cleared rapidly.
 
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People forget that after the Apollo program began flights, NASA discovered that the marvelous F-1 engines were in fact reusable. Estimated for up to 10 flights each. But by that point no allowances in mission architecture had been made for their recovery.
 
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