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Space Technology

NASA Sticking To Imperial Units For Shuttle Replacement 901

JerryQ sends in a story at New Scientist about the criticism NASA is taking for deciding to use Imperial units in the development of the Constellation program, their project to replace the space shuttle. "The sticking point is that Ares is a shuttle-derived design — it uses solid rocket boosters whose dimensions and technology are based on those currently strapped to either side of the shuttle's giant liquid fuel tank. And the shuttle's 30-year-old specifications, design drawings and software are rooted in pounds and feet rather than newtons and meters. ... NASA recently calculated that converting the relevant drawings, software and documentation to the 'International System' of units (SI) would cost a total of $370 million — almost half the cost of a 2009 shuttle launch, which costs a total of $759 million. 'We found the cost of converting to SI would exceed what we can afford,' says [NASA spokesman Grey Hautaluoma]."
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NASA Sticking To Imperial Units For Shuttle Replacement

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  • No, the real reason s that Reagan killed all the funding to go metric. We were well on our way to finishing the conversion. by the end of the eighties we would have been metric.

    No no one want s to 'increase' taxes to pay for anything. Seriously, a billion dollars and 8 years we would be done with this crap.

  • Horses Asses (Score:5, Interesting)

    by the phantom ( 107624 ) on Wednesday June 24, 2009 @11:09AM (#28452729) Homepage
    This email goes around archaeological circles every once in a while (I'm sure it goes around other circles, too), and I just got a new copy of it from my uncle yesterday, so it seems as good a time as any to share:

    People are always asking why we do things the way we do. Well, here is the reason: railroad tracks.

    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? 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 the 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 all had the same 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. And you thought being a horse's ass wasn't important? Ancient horse's asses control lots of things...


  • by Arthur B. ( 806360 ) on Wednesday June 24, 2009 @11:10AM (#28452747)

    No it's not. I've was born and raised in France, moved in the US at 23, 4 years ago. The only unit I'm still uncomfortable with is F (also one of the stupidest) I have no problem thinking in inches, miles, gallons, ounces without converting.

  • $370 million? (Score:3, Interesting)

    by sanosuke001 ( 640243 ) on Wednesday June 24, 2009 @11:10AM (#28452749)
    What the hell are they spending this money on? If they paid their engineers $150,000/year, they could hire almost 2500 engineers for a year-long project. It's not like they're building anything new or buying raw materials; they just need someone to re-draw plans with new measurements in a different system. The fitting/testing for the Ares should already be budgeted for so it shouldn't fit in with this cost. No wonder we're in debt...
  • Conversion Adversion (Score:2, Interesting)

    by BStorm ( 107974 ) <bill@EEEmcleanso ... inus threevowels> on Wednesday June 24, 2009 @11:17AM (#28452845)

    "the shuttle's 30-year-old specifications, design drawings and software are rooted in pounds and feet rather than newtons and meters. ... NASA recently calculated that converting the relevant drawings, software and documentation to the "International System" of units (SI) would cost a total of $370 million" Nearly half a billion dollars to convert into SI units (I've added the required cost overruns)?! Wouldn't all the relevant drawings, software and documentation have to be converted into machine readable formats that are more appropiate for use with today's sofware and document management systems? Is the estimated cost for the SI conversion, or more likely as I suspect the cost of bringing the design information into more appropiate formats.

  • by Lumpy ( 12016 ) on Wednesday June 24, 2009 @11:17AM (#28452851) Homepage

    Most Americans cant picture a mile. picturing a kilometer is easy, it's very close to 7 city blocks.

    Or for you suburbians the distance from abercrombie to starbucks.

    It's easy if you simply use it. Problem is ask any of your co-workers how big an inch is and most will be very wrong.

  • Re:Oh the Humanity! (Score:5, Interesting)

    by gnick ( 1211984 ) on Wednesday June 24, 2009 @11:25AM (#28452963) Homepage

    Wonderful +1 Welcome to the real world

    Also, SI conversion with stimulus $$ is one of the better ideas I've heard. It creates jobs (and ones that require at least basic education instead of just the ability to pour and smooth asphalt.) Hell, we could have even have offered basic training for people that would be involved in the more trivial but labor intensive efforts.

    Mass conversion to SI requires some manual labor (switching road signs, etc), a lot of public awareness stuff, and a lot of Associate-level tech folks (and probably higher-level for review). You know who building a duck pond employs? 4 guys with heavy equipment (or 50 with shovels) and some ducks.

  • Cars! (Score:2, Interesting)

    by tburke261 ( 981079 ) on Wednesday June 24, 2009 @11:43AM (#28453263)

    The only units I would like to stick with in the U.S. are all automotive-Horsepower, Torque (foot pounds), PSI, Quarter Mile and 0-60mph. Yes 0-100kmph=0-62mph, but that's still not accurate. Some cars are designed to redline in second gear at 60mph so they only need one shift to do 0-60mph, while they may need to hit third for 100kmph. Otherwise, metric is fine for distances, weights, volume, etc. It makes doing technical business with international companies difficult, and although the U.S. doesn't want to change I believe it would be a good use of the stimulus money.

  • I think the UK is busy converting mostly to metric system, so maybe some UKians can chime in with their experience?

    Almost everything now metric. Exceptions are for beer and milk (pints, though milk is also sold in metric units; total muddle), spirits (fractions of a gill) and road distances (miles). Next to nobody uses imperial weight measures any more.

    Beer and spirits are imperial because it would take a major piece of legislation to change. (English law is very very strict there, and pints and gills do have precise metric definitions these days...)

  • Re:Horses Asses (Score:5, Interesting)

    by Kjella ( 173770 ) on Wednesday June 24, 2009 @11:59AM (#28453555) Homepage

    That must be one of the weakest "false" results I've seen on Snopes. As it says itself:

    Origins: This is one of those items that although wrong in many of its details isn't exactly false in an overall sense and is perhaps more fairly labeled as "True, but for trivial and unremarkable reasons."

    In fact, it collaborates that the English railway was made in the same size as double-horse carriages, that the US share that width because they shared tools and that it's the dominant standard today since the northern US won the civil war. It's a bit of a stretch that double horse carriages were popular only because the romans did it, but they certainly did do it first and built a massive network of them.

    Finally, on the space shuttle thing snopes is just being silly. The largest carriage in the table listed by snopes is 9-10 feet. According to wikipedia the shuttle boosters are a little over 12 feet. So while the part about being "slightly wider than the track" is a liberal description, it's certainly possible they couldn't be built bigger because the tunnels aren't bigger.

  • by camperdave ( 969942 ) on Wednesday June 24, 2009 @12:08PM (#28453701) Journal
    Yes the SI units are pegged to arbitrary things but they are not arbitrarily pegged to *eachother*.

    Actually "imperial" units [] are pegged to SI units. Since July 1, 1959, the the inch, foot, yard, and mile have been defined on the basis of 1 yard = 0.9144 meters. The pound is defined as exactly 453.59237 grams.
  • by conspirator57 ( 1123519 ) on Wednesday June 24, 2009 @12:58PM (#28454593)

    because base 10 is always the best answer? as a nerd i'd expect you to want a base 2 or derivative (base 16) system.

  • by clone53421 ( 1310749 ) on Wednesday June 24, 2009 @01:15PM (#28454859) Journal

    Yeah... stupid arbitrary decimal system.

    Speaking of base systems... US fluid units: perfect for computer nerds!

    1 gal = 100 qt
    1 qt = 10 pt
    1 pt = 10 c
    1 c = 1000 fl oz

    So, 1 gal = 10000000 fl oz... one unsigned byte holds almost 2 gallons!

    Bonus points if you learn to cook... chicks dig guys who can cook, right? Who knows, they might even be so impressed by your cooking abilities that they won't roll their eyes at you when you try to tell them how nice the binary system would be for measuring liquids...

  • by clone53421 ( 1310749 ) on Wednesday June 24, 2009 @02:04PM (#28455833) Journal


    1 gal = 4 qt = 8 pt = 16 c = 128 fl oz


  • by Anonymous Coward on Wednesday June 24, 2009 @05:01PM (#28458653)

    How many 4.19in lengths can be cut from 6y ?

    None. For woodworking we generally subdivide inches by powers of two. There is no scale in my workshop that will allow me to mark a 4.19 inch cut without a reference piece. I think if you measure it again you'll find that the actual length needed is 4 3/16 inches.

    If I was estimating, I'd be generous and use 4 1/4, which means four pieces per 17 inches, or 8 pieces per yard with 2 inches left over. That's 48 pieces in six yards + 2 pieces in the remaining 12 inches = 50 pieces and 3 1/2 scrap. Accounting for the extra 1/16" per piece, you'll notice that that comes to 50/16 inches, so we actually have enough scrap (6 inches and change) for one more piece for a total of 51.

    No calculator, no pencil, and no converting 6 yards into inches.

    Certainly it isn't as straightforward, but it is as easy for me to do in my head as dividing 60000/419.

1 Mole = 007 Secret Agents