The shuttle based on a horses a$$?

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alexzogh

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I can't vouch for the story below, but it sure does fit into my internal paradigm of the shuttle design being from the posterior of a horse :>


The horses a$$

The US standard railroad gauge (distance between the rails) is 4 feet, 8.5 inches. That's an exceedingly odd number.

Why was that gauge used? Because that's the way they built them in England, and English expatriates designed the US railroads.

Why did the English build them like that? Because the first rail lines were built by the same people who built the pre-railroad tramways, and that's the gauge they used.

Why did 'they' use that gauge then? Because the people who built the tramways used the same jigs and tools that they had used for building wagons, which used that wheel spacing.

Why did the wagons have that particular odd wheel spacing? Well, if they tried to use any other spacing, the wagon wheels would break on some of the old, long distance roads in England, because that's the spacing of the wheel ruts.

So who built those old rutted roads? Imperial Rome built the first long distance roads in Europe (including England ) for their legions. Those roads have been used ever since.

And the ruts in the roads? Roman war chariots formed the initial ruts, which everyone else had to match for fear of destroying their wagon wheels. Since the chariots were made for Imperial Rome, they were all alike in the matter of wheel spacing. Therefore the United States standard railroad gauge of 4 feet, 8.5 inches is derived from the original specifications for an Imperial Roman war chariot. Bureaucracies live forever.

So the next time you are handed a specification/procedure/process and wonder 'What horse's ass came up with this?' , you may be exactly right. Imperial Roman army chariots were made just wide enough to accommodate the rear ends of two war horses. (Two horses' asses.) Now, the twist to the story:

When you see a Space Shuttle sitting on its launch pad, there are two big booster rockets attached to the sides of the main fuel tank. These are solid rocket boosters, or SRBs. The SRBs are made by Thiokol at their factory in Utah. The engineers who designed the SRBs would have preferred to make them a bit fatter, but the SRBs had to be shipped by train from the factory to the launch site. The railroad line from the factory happens to run through a tunnel in the mountains, and the SRBs had to fit through that tunnel. The tunnel is slightly wider than the railroad track, and the railroad track, as you now know, is about as wide as two horses' behinds.

So, a major Space Shuttle design feature of what is arguably the world's most advanced transportation system was determined over two thousand years ago by the width of a horse's ass.
 
This is mostly urban myth...

Old news...

The SRB segments DID have to fit within the Railroad "Plate" specifications that determine car length, curve limits, height and width limits, etc....

Had the SRBs NOT been made in Utah they could have been MUCH bigger-- see some of the Saturn upgrades and Nova solid vehicles that proposed up to 33 foot diameter SRM's for first stages, sometimes in clusters!

Aerojet built the 260 inch SRM and static tested it in Florida before the project was cancelled... It was to be a replacement first stage for Saturn IB and a stap-on booster for Saturn V and various follow on vehicles... It was a monolithic case design (one piece-- no segments) and was EXTREMELY heavy due to having to be moved fully fuelled from the factory to the launch pad (as are SRB's, which are broken down into segments to make moving them easier).

SRB's are heavy and expensive, and we would do better with kerolox boosters... shame that SRB's are even being considered at all post-shuttle...

Later! OL JR :)
 
Luke...I always enjoy reading the totally accurate facts & info you post........but in this case, I prefer the 2 Horses A$$'es as "historical correct" info...after all, Julius Cesears next idea had to be the Shuttle Program!
 
Luke...I always enjoy reading the totally accurate facts & info you post........but in this case, I prefer the 2 Horses A$$'es as "historical correct" info...after all, Julius Cesears next idea had to be the Shuttle Program!

Hehehe... well, it's a good STORY anyway... LOL:)

Yer welcome...

Later! OL JR :)
 
The big difference is that the AJ-260 1/2 length SRM was built at the cape so transportation was not an issue.

https://www.astronautix.com/engines/aj2602.htm

It still was not as economical or convenient or as high performance as a LOX/kerosene liquid.

Bob

I think you mean they were built in FLORIDA... at a site NEAR the Cape... the half length motor casing was lowered into a test stand INVERTED and then the propellant cast 'in-situ'... when it was cured, the mandrel was extracted (read somewhere it took 50,000 lbs of force to extract it) and then later the engine was prepped for ignition and test fired... For ignition they installed a solid rocket motor IN THE NOZZLE and lit it off, which ignited the propellant in the big motor and blew the smaller SRM casing out of the nozzle, which was tethered to come down in a 'controlled' crash some distance away...

The program was cancelled and the spent casing still sits in the underground "silo" test firing cell in Florida... the property recently passed to the private sector IIRC...

The full length 260 inch SRM would have weighed about 2-3 million pounds IIRC... it would have been an absolute MOTHER BEAR to move... the only truly "viable" way was by water... It was proposed for everything from a monolithic first stage replacement for Saturn IB (which would have about doubled its performance) to strap-on boosters for uprated Saturn V's, to clustering ten of them around a new 70 foot diameter 50 million pound thrust at liftoff monster booster capable of delivering 1.5-3 million pounds to orbit in a single shot...

All these proposals I've outlined and posted the relevant pics of over in the scale section under the "NASA Study Summary" series...

Absolutely correct they weren't anywhere NEAR as efficient as kerolox boosters... and the fact they had to be handled FULLY FUELLED, unlike kerolox boosters which are basically "full of air" when they're moved to the pad, and therefore much lighter, isn't to be underestimated either...

Later! OL JR :)
 
SRB's are heavy and expensive, and we would do better with kerolox boosters... shame that SRB's are even being considered at all post-shuttle...

If SRB's are less efficient and more expensive why would they be used? I can only assume safety, except, well, you know....Challenger. Maybe the simplicity; it is difficult enough to maintain all the apparatus for the shuttle main engines, adding more would multiply the opportunities for failure and launch delay. I'm sure I'll get the standard conspiracy arguments but I really would like to hear any intelligent opinions.
 
Something to remember in all of this is that the SRBs are already man-rated, which makes their use much easier than trying to get a new motor approved for use on manned spacecraft.

Also, the whole "horses derriere" bit was perpetuated by the TV series "Connections". I remember seeing an episode with that as a big part of the episode.

-Kevin
 
I assume SRB's are used mainly due to the consistency of pre-manufacture process. The testing/data of ingredients used should be easier to replicate and tailor-make for the individual use. Lox/Kero and other liquids usually have more inconsistent behavior due to tempature,baro pressure and refinery processes. When mixed "on the spot", I believe the results are not as "exactly as tested" as a pre-manufactured SRB made in a controlled setting that completely matches the test approved subject........At least thats the main reason I believe for using SRB's over other propultion
 
SRB's are heavy and expensive, and we would do better with kerolox boosters... shame that SRB's are even being considered at all post-shuttle...

If SRB's are less efficient and more expensive why would they be used? I can only assume safety, except, well, you know....Challenger. Maybe the simplicity; it is difficult enough to maintain all the apparatus for the shuttle main engines, adding more would multiply the opportunities for failure and launch delay. I'm sure I'll get the standard conspiracy arguments but I really would like to hear any intelligent opinions.

Politics, plain and simple...

ATK has had the best lobbiests in the business, and has had (until this last election) one of the strongest 'pro-space' senior Congressional delegations writing those gov't checks to them and looking after their interests in DC. The DOD loves them; it keeps the price of solid propellants down for the military uses and keeps the 'talent pool' for large SRMs in place if/when they ever need/get an upgraded ICBM at some point... of course the military doesn't love them enough to use them on their EELV's, except as small booster units with high use numbers (flight rates) and as expendables, which lowers the costs considerably through economies of scale. None of this does ANYTHING to make SEGMENTED SRB's more affordable for NASA.

When the shuttles were grounded after the Challenger and Columbia disasters (nearly said accidents but neither one was an accident; they were deliberate gambling against previously known issues and concerns, and they lost), the SRB program cost well over a BILLION DOLLARS per year just to keep the lights on and the folks on the payroll, so they'd be there ready to resume making SRB segments when the shuttle started flying-- that billion bucks + was when NO SRB'S were being built or flown-- that's SIMPLY THE OVERHEAD to keep the lights on and the program alive, to keep the factory 'open for business' as it were... Actual ops costs are higher still... You can look up the figures if you want exact amounts...

Add in the fact that the SRB's have maxed out the Saturn/Shuttle infrastructure at KSC and if you want BIGGER SRB's you're going to have to do over a billion in renovation and beef-ups to the VAB, crawlers, crawlerways, pads, and MLPs in order to support them (granted some of which needs to be done anyway, especially the pads and MLPs) and then look at the numbers, and SRB's are a pretty lousy deal... We could do MUCH better with new kerolox boosters-- they're almost limitless in upgrade capabilities compared to SRB's before they start severely impacting the infrastructure, and their performance and safety is MUCH higher... If anything goes wrong while you're riding a burning SRB, you're pretty much done. There isn't much credible escape (including the LAS escape tower on Orion that was supposed to be able to pull an Orion off a malfunctioning Ares I booster intact-- which it WAS capable of, BUT, when range safety presses the 'destruct' button the capsule will be descending through a starburst of 4,000 degree burning chunks of BP filling the skies-- nylon parachutes tend not to like that so much). Shuttle has NO credible escape plans until after SRB burnout/sep. Also, aborting off a liquid propellant vehicle is MUCH easier, since the engines are programmed to shut down just before the abort engine lights... an SRB CANNOT be shut down and continues to "chase" the aborting capsule until range safety detonates the linear shaped charges on the casings and "unzips" them, allowing the SRBs to rupture and essentially 'cato', throwing burning chunks of propellant all over the sky, through which the capsule must descend. Liquid propellant rockets are unzipped by LSC's as well, but it simply dumps their propellants into the atmosphere which then deflagrate in a single, rapidly cooling fireball, and that left WELL behind the escaping capsule...

SRB's limit the upgrades you can make to your booster... they simply just can't get much bigger without having to push the RESET button on the whole infrastructure and start over... the 4 segment boosters nearly max out the crawlers and crawlerways now-- the 5 segment boosters were over the top. Ares 5 went to 5.5 segment boosters and STILL needed more performance; there was even scuttlebutt about possibly going to 6 segment boosters, but the performance gains are small and the infrastructure and cost impacts are BIG. There have been various designs for monster boosters using 3 or even 4 SRB's (or more) but these are TOTALLY unrealistic-- they simply weigh TOO MUCH to ever be able to stack and move at KSC-- unless you want to simply implode the VAB and pads and start from scratch with a "stack on the pad" paradigm (like all rockets were done before the VAB came about). Similar upgrades to a kerolox booster (tank stretches, upgraded engines, more engines, etc) are MUCH easier to integrate into the existing infrastructure without requiring massive changes, and give WAY WAY more performance increase per pound of weight added (due to greater ISP efficiency than solids) and a better return on costs (again due to efficiency and minimizing unnecessary changes required by enlarged SRM's).

SRB's were originally chosen for shuttle because 1) they were seen as providing 'cheap, high liftoff thrust' 2) were simpler to reuse than LRB's were seen to be 3) were cheaper to develop and flight qualify than competing pressure fed and turbopump fed LRB designs. Money was at a premium and whatever would save development costs up front, regardless on their problems or future limitations, was seen as good. There were plenty of folks at NASA who thought the SRBs were a mistake then and still do. NASA used inflated flight rates of ~50 flights a year (almost weekly) to justify the shuttle and SRB's-- at those flight rates, SRB's would indeed be quite cost effective. Of course they NEVER achieved over a fraction of that flight rate; subsequently both shuttle and the SRB's have been very expensive on a per-unit/per-flight basis... This is part of the reason that the 'small' SRM's used with EELV are more attractive-- each flight uses a 'fistful' of them, so that ups the flight rate on a per-unit basis and achieves economies of scale higher and sooner...

When you add it all up, the SRBs have really outlived their usefulness-- they add a LOT of expense and limitations that you simply wouldn't have with an all-liquid kerolox booster, or competing designs such as AJAX which use an ET-based SSME powered core stage using Atlas V's as kerolox LRB's...

Hope that gives you something to consider...

later! OL JR :)
 
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