Alternate space shuttles

[fasquardon]

Over in the "Carter lets the Space Shuttle die" thread the conversation has been drifting towards a more general discussion on alternate space shuttles.

So here's a new thread for alternate space shuttles, I'm especially interested in what kind of alternatives would be possible with a PoD AFTER 1972.

To start the ball rolling, here's a couple quotes from chapter 9 of "The Space Shuttle Decision"

This table included the four cases cited by Low in his memo to Myers of December 13, and reviewed by Myers. Case 1 was the OMB shuttle; Case 4 was the Shuttle NASA wanted and now apparently would not have. Following standard custom, the option Fletcher proposed was right in the middle as Case 2A. 11

Fletcher privately knew that he could go still lower. Talking with Low, he decided that they could accept something as small as 14 x 40 feet with 40,000 pounds. The two men then went to an afternoon meeting with White House and OMB officials: Shultz, Weinberger, Flanigan, David, Rice and Rose. Shultz was now the key man; he headed the OMB, he was Rice's boss, and he had Nixon's ear.

Shultz looked at NASA's presentation and decided that the only thing that made any sense, as NASA had said all along, would be the full-size version, Case 4. Shultz, however, did not press this point for Rice objected vigorously. Rice's staff was still active; only one day earlier, his economist John Sullivan had sent him a memo arguing anew that the most cost-effective system was still the Titan III. The meeting broke up with no decision. Fletcher and Low, however, came away fairly confident that they would at least get Case 2A, which they had recommended. Indeed, Shultz's support, however tentative, allowed them to hope that they might even win the full-capability Case 4.

Rice again prevailed, as he talked further with Weinberger. In a phone conversation with Fletcher, Weinberger stated that he wanted NASA to look at a 14 x 45-foot Shuttle-with 30,000 pounds of payload, only two-thirds that of Case 2A. In Low's words, "Fletcher came close to telling Weinberger to go to hell but restrained himself perhaps better than I could." Fletcher then phoned Shultz and talked with him at length. Shultz remained unwilling to make a decision, but recommended that NASA should take one more look at Rice's request.

Although Rice was holding firm on a weight of 30,000 pounds, he now was willing to budge slightly on payload size, for Sullivan's memo had discussed a 12 x 40-foot shuttle with twin solid boosters. Though this configuration would carry no more weight than a Titan III, it could fly with the boosters of a Titan III: 120-inch solid motors that were in production and had known costs. Such a Shuttle still would not match the cost-effectiveness of the Titan III itself, but it would come close. In Sullivan's own analysis, that [407] Titan would save only $100 million when compared to that Shuttle. Within the OMB, this was as near to an endorsement as any type of shuttle was likely to receive.

Low phoned Rice and asked him to put his questions in writing. Rice replied that he might have further questions subsequently, but he drew up a set of queries and sent it over to Low late on Friday evening, which was New Year's Eve. Low discussed them with Fletcher and Myers over the weekend; on Monday, January 3, they completed their response. A sampling will illustrate the exchanges:

Loose Ends I: A Final Configuration

Now that Shultz had handed NASA its Shuttle on a silver platter, the agency had to decide how it would look. The question of choosing a booster was still up in the air, and it was far from clear that the Shuttle indeed would be a TAOS; liquid-fueled boosters designed as conventional first stages were making a strong comeback. Similarly, the agency could not simply walk away from Fletcher's alternative of 14 x 45 feet and 45,000 pounds; NASA itself had proposed it, and it merited additional attention because it offered the potential advantage of being able to use existing 120-inch solid rocket motors. Further study of this design would also discourage the OMB from complaining that NASA once again was abandoning a good possibility with unseemly haste.

From the sound of it, there was a real chance that the Shuttle might end up with a 12-by-40 to 14-by-45 30,000 lbs to 45,000 lbs payload bay and Titan III srbs.

That's pretty interesting, since Titan SRBs would be far cheaper (due to being smaller, needing no development money and due to fixed costs being spread over both shuttle and Titan launches), probably safer (since they have all the Titan III launches to draw data from and any upgrades to the shuttle SRBs can be tested on unmanned Titan launches before being used on the shuttle), would enable both the titan system and the shuttle to be upgraded (since money for upgrades for both launch systems can be pooled). Also, from what I've read, United Technologies (who made the Titan srbs) were a more responsible company than Thiokol.

I understand that the Titan srbs also gave a smoother ride.

Also, a smaller shuttle might have formed the basis for a practical shuttle-c or an advanced Titan with a new hydrolox core stage powered by shuttle main engines. (I would guess a shuttle-c type system with Titan srbs would be able to lift something on the order of 25-30 tonnes to LEO.)

Seems like an approach that could have led to a much more practical shuttle.

fasquardon

 

[Archibald]

As I said in the other thread "Right side up" got an interesting, clever shuttle derived from Saturn INT-20 (S-IC + S-IVB) - a flyback S-IC + S-IVB + a lifing body.

Those were the days... in 2002 I got access to Internet for the first time and found this website. http://www.pmview.com/spaceodysseytwo/spacelvs/

My gut feeling about the space shuttle : no design could both please the U.S military (the Air Force + NRO and their enormous KH-9 spysat) and NASA insane flight rates driven from mathematica, RAND, studies.

My personal pet shuttle designs has an orbiter with internal LOX tankage, LH2 external, drop tank.
The engine would be the XLR-129, a nice in-between a J-2 anda SSME, which had been partially developed for the military ISINGLASS rocket spy plane.
Boosters are single-stick F1As, two or four of them. Can they be recovered ? Energiya Buran explored varied solutions, none very satisfying. Only much later did SpaceX Falcon 9 happened. I don't think SpaceX F9R- like landings could have been possible by 1970 or 1980.

There was a couple of excellent threads at nasaspaceflight.com.

Alternate Joint NASA/USAF "STS" System. - NASA Spaceflight Forum

What would a better STS Have Looked Like? - NASA Spaceflight Forum

 

[fasquardon]

Here's a question for folks:

Under what circumstances is it plausible to see continued upgrades of the shuttle system from 1981 to whenever the shuttle is taken out of commission? (I suppose in OTL they did lighten the ET and up the throttle on the SSMEs, but I am thinking of a systematic series of upgrades throughout the shuttle's life, meaning things like liquid booster rockets and the aft cargo pod become possible.)

Is it enough to have NASA be more cautious and fix the O rings before the Challenger goes kabloey? Would we need the shuttle to be smaller, to make upgrades more desirable?

fasquardon

 

[Archibald]

The space shuttle as it stood could have been improved. I'm not a great fan of flyback boosters. But the ASRM sounded a good update. They were also discussion 5-seg boosters before STS-107.
My favorite shuttle upgrade is the Aft Cargo Carrier.
https://www.wired.com/2012/05/shuttle-with-aft-cargo-carrier-1982/

The Block III SSME sounded like a major, positive upgrade. With that channel wall nozzle. I wish I could find more documents about the Block III SSME (or SSME Block III). Even Google Books turns nothing.

Also the non hypergolic OMS pods. kerosene and H2O2 would have been interesting (Buran, did you said Buran ? I said Buran).

I would say Block III SSME, ASRM and ACC.

 

[fasquardon]

The space shuttle as it stood could have been improved.

But what PoDs could lead to the shuttle being improved more?

(And I'd not heard of the new OMS pods and the block III SSME - if you do find some documents on the latter, please do share!)

fasquardon

 

[Archibald]

Well, my favorite POD is to remove the Shuttle foolish flight rates that drove STS-51L into the wall. I'd say - by 1969 the space shuttle was to be a smaller, crew and cargo taxi to a space station. Well, give it back that role AND NOTHING ELSE.
My favorite POD is that Skylab A cannot be repared in June 1973. Skylab B would have launched a year later. with a little luck, it would have lasted until STS-2 late 1981. Then, Congress being Congress, people like Proxmire would have told NASA "screw any new space station and do with Skylab B". The shuttle would have reverted to its original role, screwed the insane flight rates, and STS-51L would have never happened.
The bottom line is that NASA ( a public entity) pushed the manned shuttle as an Ariane competitor to launch satellites. That was IN-SA-NE. By keeping Skylab B I'm trying to throw a wrench into that insanity.

 

[Uli_Stoiber]

Two man cockpit with ejection capsules from B-70 and a Crew module for 2-3 astronauts with ejection capsules as well. Better even, ability to land on autopilot for cargo flights and have a crew module (4-5 astronauts with escape capsules) in the bay, with spacelab for science missions or other mission payload for construction / sattelite maintainance. Here would be the possibility of the two fatal accidents to have occured on uncrewed flights and / orthe challenger accident with a chance of survival. Payload for uncrewed flights in the 35 to 40 ton range, which would allow to launch a lot of commercial satteltes at once and bigger space stazion modules.

 

[BowOfOrion]

I think one of the more significant POD's for Shuttle improvement is to eliminate the Air Force's influence. The need for crossrange capability led to some significant changes in the overall design.

My theory is that Shuttle tried to do too much too quickly. It's akin to trying to build a DC-8 in 1915. If you want something to carry cargo to orbit, then you need certain capabilities. If you want something to ferry crew to a station, there are a completely different set of needs. If you want something that can fly over Russia, drop a payload and come back in one orbit, that's a different set too. OTL Shuttle had to serve a lot of disparate functions.

Far too many cooks in its engineering kitchen.

This will not be the last time you hear me speak on this matter...

 

[Archibald]

What really piss me off and baffles me with Air Force (NRO) involvement in the Space Shuttle is that
a) NASA enlisted the Air Force to boost the flight rates and more importantly, to boost support in Congress
b) The Air Force agree but at a condition: they ramed the 60 ft long payload bay into NASA to launch the KH-9 big spysat
and then
c) they did not helped NASA crusade to get the Shuttle funded in Congress. Not at all. They were perfectly happy with the Titan III (a rocket that launched the first KH-9 in June 1971)
d) Once NASA was committed to the space shuttle they dragged their feet - there was little enthusiasm about moving military satellites to the Space Shuttle.

At the end of the day the shuttle got an oversized payload bay to launch the KH-9 spysats... except none of these satellites ever rode a shuttle to orbit.

So when you think about it, NASA would have been better NOT enlisting the Air Force and leave the Titan III alone.
Alas, NASA couldn't afford such a decision. The Shuttle needs to fly a crapload of missions to earn money, 40 to 60 flights a year. As such, it needed all these military satellites, and it needed to slain the Titan III.

The unforgiving truth is that with flight rates of 5 to 25 launches annually, the Titan III (an expendable launch vehicle, ELV) made more sense than the space shuttle (a RLV). Every single ELV/ RLV economic studies since 1966 pointed to that fact (RAND corp. and many others).

A very little know factoid is that a large bulk of the 1960's launches were NRO Agena-based spysats. Between 1960 and 1985 no less than 250 Agena spysats were flown (KH-4 CORONA, KH-7 & KH-8 GAMBIT)
Alas, by 1971 all these cheap spysats were remplaced by a couple of expensive, long-duration big spysats: the KH-9 and KH-11.

 

[Archibald]

Here is the final answer to the space shuttle payload bay length, why it was 60 ft. Yours truly asked the question to one of the best space historians on one of the best space forums out there.

https://forum.nasaspaceflight.com/index.php?topic=26820.msg1641905#msg1641905

By contrast we still don't really know about the width - probably because of space station module diameter.

So you can see that NASA was in control of the space shuttle payload bay WIDTH, but not LENGTH. Can you believe that ? Tom Heppenheimer SP-4421 "The space shuttle decision", chapter 7 (A shuttle to fit the budget) shows that 40 ft*15 ft payload bay orbiters were considered but NASA rejected them (or perhaps the military)

There is a great expression (- in French - I wasn't sure it existed in English)

https://en.wikipedia.org/wiki/"Left-Wing"_Communism:_An_Infantile_Disorder

Lenin critiques the Workers Socialist Federation's opposition to Parliamentary action (SNIP) He concludes that the party would gain whether or not Labour accepted the offer. In a famous turn of phrase, he says that they should support Labour General Secretary Arthur Henderson "in the same way as the rope supports a hanged man"

A good case could be make that Lenin's words truly applies to Air Force / NRO support of NASA in the space shuttle program.

"The NRO supported NASA in his congressional fight for the space shuttle - in the same way as the rope supports a hanged man".

 

[Admiral Beez]

But what PoDs could lead to the shuttle being improved more?

I'd like a shuttle that can actually enter interplanetary space. Humans haven't left the thermosphere since 1972, when I was one year old. Will I have to wait another 45 years for a repeat?

 

[fasquardon]

12 posts in and plenty of people have chimed in with improvements they think could have been made or should have been made, but there's been no discussion of how those things could have happened.

Do people just think that there is no plausible way that NASA would go for a smaller shuttle boosted by Titan SRBs? No way they'd get money for liquid rocket boosters? Or upgraded the OMS systems? No way that NASA could rid itself of the airforce-imposed design specifications? No way that NASA would be allowed to develop the Aft Cargo Carrier?

Alas, NASA couldn't afford such a decision. The Shuttle needs to fly a crapload of missions to earn money, 40 to 60 flights a year. As such, it needed all these military satellites, and it needed to slain the Titan III.

The unforgiving truth is that with flight rates of 5 to 25 launches annually, the Titan III (an expendable launch vehicle, ELV) made more sense than the space shuttle (a RLV). Every single ELV/ RLV economic studies since 1966 pointed to that fact (RAND corp. and many others).

The push for high flight rates is basically the original sin of the shuttle program. In my view, the strongest advantage of any PoD that forces NASA to settle for a smaller shuttle is that it basically forces NASA to build an experimental vehicle, rather than a full-on space bus to take all US orbital traffic.

I'd like a shuttle that can actually enter interplanetary space. Humans haven't left the thermosphere since 1972, when I was one year old. Will I have to wait another 45 years for a repeat?

Not terribly efficient. Carrying the heavy SSMEs, the wings and the tiles into interplanetary space would make the shuttle a rather inefficient deep space vessel.

NASA would really need the OTV and a specialized capsule for activity in interplanetary space.

I can't really think of any plausible PoD that would lead to the OTV being developed. The closest thing would be to somehow find a way to save the Saturn IVB and then see it upgraded as time went on. (The J-2 would have been an amazing engine for a deep space reusable rocket as well, since it pretty much didn't wear out.)

I did have an idea for a TL that might lead to NASA having both the Saturn IVB and a small shuttle launched on a Saturn IB class launcher, I'm not sure if it is terribly plausible though. (The rough outline is this: NASA is forced to develop a "mini" shuttle of about 30 tonnes to be launched by an uprated Titan-derived booster. However, due to problems uprating the Titan that much, worries about being over-dependent on one technology set and desires by NASA to have their "own" rocket and preserve as much of the Apollo hardware as possible, NASA ends up choosing a rocket with Castor SRBs, 7 clustered Thor tanks feeding RS-27 engines, and a Saturn IVB as a second stage. A Saturn IB reborn.)

Another PoD for enabling America to do more in deep space: NERVA isn't cancelled and the program produces a practical deep space nuclear OTV engine.

fasquardon

 

[trurle]

12 posts in and plenty of people have chimed in with improvements they think could have been made or should have been made, but there's been no discussion of how those things could have happened.

Do people just think that there is no plausible way that NASA would go for a smaller shuttle boosted by Titan SRBs? No way they'd get money for liquid rocket boosters? Or upgraded the OMS systems? No way that NASA could rid itself of the airforce-imposed design specifications? No way that NASA would be allowed to develop the Aft Cargo Carrier?

The launch rate question was a prime factor in determining the Space Shuttle fate. Making a root-cause analysis, i can claim several factors were to doom any "Space Shuttle" development by reducing launch rate below useful threshold.
1) The atmosphere friction - launching large (>5 tons) payloads is very efficient from the point of maximizing mass fraction to orbit. Can be fixed with high mountain or stratospheric launch system.
2) Immature electronics of 198x. Weight of control blocks approaching useful functionality was measured in tens of kg (limiting minimal weight of spacecraft). Can be fixed with earlier microprocessor revolution.
3) Immature communications of spacecraft. Space-faring states resorted to sending a special naval vessels fitted to support uplink/downlink, but it was costly and awkward. Radio ground stations and automatic wireless relays needed much more sophistication to support Space Shuttle launched fleet of satellites. TRDS satellites were too late and not enough. What needed was the early equivalent of Iridium, plus ground-based LEO tracking stations wired to earlier Internet - to support all the (smaller) satellites flown by high-rate Space Shuttle
4) No strategy or hardware for fast (<6 hours) orbital rendezvous. Absolutely critical if you launch something in small pieces and assemble in LEO. This is mostly mathematics and sensor tech, and may be the easiest to achieve of all 4 critical components for high-rate Space Shuttle.

With all 4 point above implemented, smaller Space Shuttle (10-30 tons orbiter with 2-10 tons payload) may be constructed. And operated with economy favourable compared to expendables. What we observed IOTL, is the pressure from payload makers (USAF and others) to launch fewer larger payloads, and the resulting problems with the Space shuttle launch rate.

The "Aft Cargo Carrier" concept was a deviation to opposite side (ever larger payloads with fewer launches). Ultimately (if implemented), it would come to ideas like "let`s extend AFT_CC, cut out wings, payload bay and cabin of space shuttle, leaving only SSME pack with fairing..wow, 80 tons payload to LEO! Absolutely disposable, but who cares if payload cost is 5-times the cost of rocket?

Regarding Titan III boosters (UA1207)?, these with thrust 1450 tons, i feel the size of single booster may be suitable for launching reusable orbiters similar to modern Falcon 9 Full Thrust payload (23 tonnes). It likely mean ~5-7 tons useful payload. With typical staging, the first staging point may be about 1 km/s at 60 km altitude, leaving SSME with a clean high-altitude nozzle. In this configuration (SSME launched after booster burnout), may be necessary to have an additional mini-boosters for just first ~20 sec to compensate main SRB stage torque until flight surfaces of orbiter become effective. The SRB nozzle must be designed to have nearly-zero torque either at burnout or start, but selecting zero-torque at start will expose (reusable) flight surfaces to undue thermal and mechanical stress at burnout, and i feel it is a bad trade-off if you think about vehicle weigh and maintenance. Partly because you may be forced to reduce start acceleration to burn-out booster at low enough altitude where launch vehicle is prevented from tumbling by full deflection of ailerons. Well..it also add pretty scary failure mode. Compromise is possible by having SSME running in parallel with SRB (as IOTL). In this case smaller control surfaces (used only at landing) are traded off for worse fuel tankage efficiency.

Using a couple of UA1207 boosters was a losing proposition from the perspective of launch rate, i.m.h.o. Control is much more straightforward though - because couple of boosters can be mounted close to launch vehicle center of mass (producing less movement of center of mass as solid fuel is being expended), instead of aft of it as in case of single SRB. Therefore, likely boosters smaller than Titan III boosters were optimal for smaller and more cost-effective space shuttle.

 

[TheHolyInquisition]

Do people just think that there is no plausible way that NASA would go for a smaller shuttle boosted by Titan SRBs? No way they'd get money for liquid rocket boosters? Or upgraded the OMS systems? No way that NASA could rid itself of the airforce-imposed design specifications? No way that NASA would be allowed to develop the Aft Cargo Carrier?

Not with OMB restrictions.

 

[RanulfC]

I'm highly upset you folks allowed me to miss this thread! Then again I've spent the last couple of days formulating a nice reply now that I HAVE found it only to have my computer crash and kill the draft

One salient point which I think we are missing is the Shuttle was designed for a specific purpose and goal which I haven't seen mentioned. Launch a crew on every flight. Really that was 'job-one' for the program with everything else tacked on in vague support of that primary mission. Payload? Ya, what ever it takes to fly as often as possible so we keep the 'manned' in manned space flight. Cargo bay size? Did you not listen to what I said? Economy? You're just being difficult now aren't you? Technology? Seriously I'm gonna slap you in a minute. Air Forc...:::smack::: you can't say I didn't warn you now go to the corner and thing about what you did...

While we can argue that a smaller, more efficient shuttle and/or semi-or-recoverable booster could have done the same it really can't because it needs to fly manned every time AND do all the other things but mostly fly manned. I'm rather surprised it's taken a dozen readings of the Shuttle Decision, etc for me to finally grasp this very basic fact but it's actually pretty obvious given the other factors involved that this was the main criteria that NASA was driving for. Once you realize that, and then see how the only way to fulfill THAT criteria AND encompass the other 'requirements' that NASA embraced to justify the Shuttle program it becomes clear that the only way to avoid the Shuttle is to start with the premise that not every flight has to be manned. Once you get beyond that the options suddenly open vastly.

Randy

 

[RanulfC]

12 posts in and plenty of people have chimed in with improvements they think could have been made or should have been made, but there's been no discussion of how those things could have happened.

Do people just think that there is no plausible way that NASA would go for a smaller shuttle boosted by Titan SRBs? No way they'd get money for liquid rocket boosters? Or upgraded the OMS systems? No way that NASA could rid itself of the airforce-imposed design specifications? No way that NASA would be allowed to develop the Aft Cargo Carrier?

In a word? No because that was unacceptable to NASA and therefore something they would not have done had they any choice. And frankly we should be aware at this point that the "Air Force" did in fact not 'force' specifications on NASA that it wasn't already willing to embrace. The big cargo bay wasn't forced, NASA had already convinced itself, (and had the math to back it up) that the only economical Shuttle required a huge cargo bay. They had in fact been told by the head of the NRO, (but since they weren't cleared to KNOW there was an NRO he was 'just some undersecretary of the Air Force to them and obviously not someone important) that a smaller cargo bay would be acceptable. But the "Air Force" (who in fact at this point were no longer directly involved with design and construction of spy satellites) told them what they wanted to hear. Delta-wings? NASA had already decided that delta wings was the most efficient wing structure and had all contractors studying them as the primary baseline. Again the Air Force told them what they wanted to hear.

So why didn't the Air Force support the Shuttle? Because the Air Force as an institution, well 'hated' is a strong word but pretty accurate in that it was officially "policy" that NASA was a useless organization that had been politically created to steal the Air Forces rightful mission of space flight. Ok, you won't find that particular 'mission statement' anywhere but you really don't need to look past statements and attitudes of the major Air Force leadership in the 60s to early 70s to see it manifest. "Technically" the Air Force had a point even in that Eisenhower had arbitrarily decided that "space" as an environment would not be treated as such but as a 'special' place that the Cold War would not enter. Air Force leaders were pretty pointed in calling this bull but that stopped neither Eisenhower or Congress from creating NASA anyway. And since this was supposed to make the Russian's do the same and obviously failed as they never bothered to separate military and civil space...

And then NASA went and sucked up most of the Air Force personnel and facilities that they had built towards the space mission. (Yes they got the other services space programs to but do I need to point out that this doesn't matter to the Air Force? ) And shortly after the Air Force steadily loses every other aspect of space except for the mechanics of launch servicing and THAT of a satellite program they have also had taken away from them?

The Air Force was going to tell NASA every and all "requirements" (the more fantastic the better even if they have to lie about it) it can make up and laugh as they try and get them approved... And then they find that in addition to taking those requirements to heart that because of it NASA will now be taking the one remaining aspect of space flight from them: the launch mission. Is it any wonder that Air Force did not 'support' the Shuttle until it was a 'done' deal?

Archibald mentioned one of those "lies" in fact. The XLR-129. It was a fantastic engine with so many advanced properties and advantages, one wonders why NASA never used it in any capacity. The simple and most obvious answer is because there was never anything to use. Bernard Schriever stated once that the Air Force had 'handed' NASA the XLR-129 and that NASA had done nothing with it and in fact suppressed it because it was not developed "in-house". If I'm feeling generous I tend to give the General the benefit of the doubt in that when he said this he was well retired and that he'd had no direct dealing with or knowledge of the XLR-129 program so it was understandable that he got his facts wrong. Most times I'll admit he probably DID know he was lying and did so anyway because he was opposed to NASA and a strictly civilian space program and was looking to bad mouth it any chance he got. In essence the XLR-129 was never more than a paper engine with a number of studies, (some still classified because they are attached to advanced recon platform studies themselves) and a few very prototype parts that were "cold-flow" (had a liquid run through them could be LH2 but at the stage there were in could very well have only been water the studies don't say) but never run as a unit in any condition. The Air Force handed NASA a series of paper studies, not a built or even tested engine in any way. Further they handed NASA a set of studies that AT THE TIME were still mostly classified. How did that work? It didn't. As a public record agency NASA generally didn't have the clearance to even READ let alone process classified materials. Technically they couldn't even ask the engine contractor, (Pratt&Whitney) about it since they weren't cleared to even know about it. It was later declassified but since P&W was bidding the Shuttle engines at the time and basing their work on that done for the XLR-129 they had a general idea of what it could do and it was in fact no where near as great as the Air Force suggested. In fact it was going to be JUST as expensive to develop at the Rocketdyne proposal SSME but not as effective so they chose the SSME instead.

And this was the environment which bred the Shuttle. Coupled with NASA's need to ensure that manned space flight remained the main focus of US space flight no matter what and the "lessons" learned from Apollo, ("You will always get the money you need when you need it because space will always be a top priority" which is the lesson they LEARNED not necessarily the one given) NASA set out to ensure it was the only space flight business in town. And the Air Force in its haste to set NASA up for a fall in fact fell on their own sword and we all ended up with the Shuttle.

Could it have been different? Of course, we're on "alt-history" after all but a lot of significant factors have to change to get there.
Gotta go tonight I hope to get more tomorrow.

Randy

 

[marathag]

2) Immature electronics of 198x. Weight of control blocks approaching useful functionality was measured in tens of kg (limiting minimal weight of spacecraft). Can be fixed with earlier microprocessor revolution.

Shuttle was flying with '50s Core Memory thru the '80s. It didn't have to.

 

[trurle]

Shuttle was flying with '50s Core Memory thru the '80s. It didn't have to.

The problem is not weight of electronics of Shuttle, but the weight of electronics of its payloads. Heavy electronics blocks prevented the development of light payloads, therefore the size of Shuttle can not be reduced too.

 

[Michel Van]

Shuttle was flying with '50s Core Memory thru the '80s. It didn't have to.

The problem is not weight of electronics of Shuttle, but the weight of electronics of its payloads. Heavy electronics blocks prevented the development of light payloads, therefore the size of Shuttle can not be reduced too.

There some misunderstanding why the STS used Core Memory in there fight computer

First: Frozen Design
As the Space Shuttle program starts in 1973, the initial hardware design was "Frozen" no major modification until Test launch.
in this case the flight Computer stick in early 1970s configuration, The best available in time was The IBM System/4 Pi AP-101
No one At NASA or USAF, thought that during 1970s the Computer technology would do a Quantum Leap to integrated circuit on tiny chip.
next to NASA expected to Launch the Shuttle in five years not eight year later in 1981.

Two: We Need Something that Work
they needed also some thing that was already in space and Worked perfect
The IBM System/4 Pi AP-101 flew on Skylab, was used by USAF in Allot aircraft like F-15
And Old Fashion 50s Core Memory has a excellent advantages nowadays almost forgotten
Robustness against forces of Launch, apathetic at conditions in Space were unprotected IC get radiation burned,
But best advantages is it could keep it information in Core Memory, wen it's computer got no electricity !
That was very helpful as Apollo 13 Command module had no electricity during return trip from Moon.

Three: NASA Bureaucrats and Budget
If something worked at NASA, the Bureaucrats keep it running, special if Capitol Hill cut the funding again.
Happen under Carter and Reagan Administration
it took to 1984 that NASA got chance to replace there old IBM computers, they bought in beginn of 1960s for Apollo program.
You know those with 50s Core Memory and using punch card to load the programs into Computer...
After Challenger the Shuttle Hardware got major upgrade, there Flight computer in 1990s
AP-101B were replace with AP-101S that had IC Chips but still worked like 1970s computer...

 

[RanulfC]

To get a significantly different "shuttle" design the "POD" has to happen somewhere almost prior to the Apollo lunar project itself because that's pretty much the point where NASA 'changed' significantly and lead to the 'big-program-which-eats-the-budget-and-focus' issues we still deal with today. Had there been no OMB budget issues we'd have had a substantially different Shuttle but I highly doubt we'd have gotten the fully reusable two stage shuttle envisioned simply because to loft the Orbiter NASA wanted would have required something like the flyback S1 and all that implies which I can't see as fiscally possible at the time.

Hopefully I can resurrect the majority of the other post I was working from the work computer on Monday

Randy