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NASA Will Go Metric On the Moon
An anonymous reader writes "Space.com is reporting that NASA has decided to use the metric system for its new lunar missions. NASA hopes that metrication will allow easier international participation and safer missions. The loss of the Mars Climate Orbiter was blamed on an error converting between English units and metric units. 'When we made the announcement at the meeting, the reps for the other space agencies all gave a little cheer,' said a NASA official."
Now if only American car companies will budge that extra 17/32" and finish going metric rather than forcing me to have 2 sets of tools for one car. Then I can "Compare Prices on Physics and Engineering" here at /.
The metric system is the tool of the devil! My spaceship gets forty rods to the hogshead and that's the way I likes it!
The loss of the Mars Climate Orbiter was blamed on an error converting between English units and metric units.
And to think when we were learning the metric system in school, the teacher told us it didn't take a rocket scientist to figure it out.
I guess he was wrong.
The theory of relativity doesn't work right in Arkansas.
Metric is a very easy system to deal with and has been adopted over a large portion of the world. Technically Canada has been metric for over 20 years. Tho things like construction has remained Imperial as we are next to the US. If not for the Us Canada would be completely metric, but since the Us is right next door, we end up in the metric camp with one foot still over in the Imperial side o things. But I don't see the Us converting to metric any time soon, but the scientific community moving to metric to do its work instead of continually converting would be a great leap in the right direction.
when the first McD's is built on the moon, I have to order a "Royal With Cheese" ?
I used to be with IT..now IT seems strange and scary to me.
I'm confused - are they only going to use the Metric system on the Moon?
or is it more like: "Dude, did you see that?! NASA totally went Metric on the Moon's ass!"
Insisting on "correct" English is like saying that there is only one, definitive recipe for chili.
I imagine this will assist the U.S. is its conversion to the metric system, something it has been trying to do for many years now.
Yeah, they started with the 2-liter bottles of soda about 20 years ago, so it looks like they're working their way down the list.
I wonder what comes next, after beverage containers, and interplanetary spacecraft.
The theory of relativity doesn't work right in Arkansas.
.. but when is the rest of the USA going to follow suit?
According to wikipedia, As of 2005 only three countries, the United States, Liberia, and Myanmar (Burma) have not converted to metric yet. Canada officially converted in 1970, but both systems get used on a day-to-day basis. Most tape measures, rulers, etc have both systems. Most older people still use imperial for most things, and younger generations seem to be mixed.
It's actually interesting that a lot of people here (Canada) use mixed units. Personally, I usually use feet if I'm estimating a distance (it's just a very convienient size - the closest metric equivalent is a decimeter, just doesn't quite cut it), and pounds and feet/inches for human weight/height. We still order a pound of wings and a pint of beer (I think you get beat up if you ask for 568mL of beer in a bar). Most other things are metric: road signs are km/h, the weather report is in celcius. Most stores sell things by the kilogram, meter, or liter/milliliter. I'm not sure what they teach kids in school now, but my generation (mid 20's) seems to be decently fluent in both systems (I remember learning how to add inches as part of learning fractions).
Speak before you think
This is a necessary, but difficult transition. Yes, difficult. Maybe it's pretty easy for the programmers, but for the mechanical guys out there (like myself), this introduces a huge relearning phase. Say, for example, I need some sheet metal to function as a structural piece. I can be pretty confident that my initial guess will be pretty close to the final thickness value if specified in imperial units. I also know what's typically readily available from suppliers (eg: 1/4" is far more common than 15/64"). Not only must I do a conversion from my ingrained inch units into "foreign" metric, but I must also look up which sizes are common.
With time, I would be just as good with metric as with imperial units. And I want to change to metric for its obvious advantages. It's just that my design confidence and productivity would falter through the transition. I'm quite sure I'm not alone on this.
IWARS.
People, in general, disappoint me. Politicians even more so.
I should preface this post with the fact that I'm in the US. When I took physics and chemistry in college we barely discussed English units. There was one class period that we talked a little about conversion from English to metric units (I don't believe we even did the opposite), and that was about it. It was just assumed that we knew metric very well already. If I graduated and went to work for NASA and had to use English measures, I think I would have to almost relearn some of the physics--it would be awkward for me to work with the non-SI units, and even more awkward to have to learn new constants (I learned the constants in metric units). So I assumed that NASA had moved away from English units long ago since it hasn't been taught in so long.
There's nothing inherently inaccurate about the measurement system itself. You can measure down to the millionth of an inch if you want. If a contractor is going to be loose with their measurements, they could just as easily say "Eh, that's about two meters" as "Eh, that's about seven feet". You can't make people measure down the the millimeter just because it's available on their measuring tape.
Warning: Apple/Nintendo fangirl. Likes her electronics cute & cuddly. May be rabid.
These NASA rebels must be stopped. The moon was claimed in the name of the United States by Neal Armstrong, we can't allow them to fruit it up by going all metric on its ass the next time they land there. We should nuke all of NASA's bases from orbit. Some one see about coordinating that with our national space agency.
It secretly amuses me when Americans (one of only three backwards countries that haven't converted) argue about keeping the "imperial" system. All of your current units of measurement have been defined relative to the metric system for the past 50 years or so. From the wiki: "One inch international measure is exactly 25.4 millimeters, while one inch U.S. survey measure is defined so that 39.37 inches is exactly 1 meter". "The pound avoirdupois, which forms the basis of the U.S. customary system of mass, is defined as exactly 453.59237 grams".
When our name is on the back of your car, we're behind you all the way!
Exhibit #1 for why Wikipedia is not to be trusted - they continue to tell half the story. (On this and many other topics, they prefer the simple and popular explanation over completeness and accuracy. [1])
MCO was lost not because of a metric conversion error - but because an increasing divergence between the planned and actual performance was ignored. The official report mentions this - but glosses over its importance. MCO was lost because NASA attempted to fly the mission on the cheap, because of this testing and analysis during the cruise phase was cut from the budget. Some analysis was done on the side by a few engineers - and their calls for a formal analysis went unheeded until too late.
[1] And before the Wikipedia cheerleaders chime in, yes - I have tried to fix many articles to correct this problem. Without exception the corrections were either reverted out or edited into meaninglessness. On Wikipedia the win goes to the editor with time on his hands or who can cite a lightweight popular article as the source of his 'facts'.
It was actually mandated back in 1975 that the US needs to convert to the metric system, check out http://www.pueblo.gsa.gov/cic_text/misc/usmetric/m etric.htm
Quote:
Congress passed the Metric Conversion Act of 1975 "to coordinate and plan the increasing use of the metric system in the United States."
but it all fell apart since there where no deadline and all based onm voluntary conversion.
From Wikipedia:
p ng
http://en.wikipedia.org/wiki/Image:Metric_system.
But the Death Star would almost certainly use Imperial units, would it not?
If you don't know where you are going, you will wind up somewhere else.
The bigger irony is that they're not even proper "english" units! The fl. oz. is slightly bigger, there are fewer fl. oz. in a pint, the ton is lighter, and have you ever heard Americans measuring their weight in stones? Perhaps they were looking for somebody else to blame for the twisted unit system, and chose the name of the country they rejected in 18th century!
Using the metric or imperial system would not matter one bit if all you're measuring is distance or volume. But as soon as you start converting distance into volume (quick question: how many cubic inches in a pint?), or thrust into velocity (quick: you apply a one-pound force to a one-pound object for one second. What's the resulting speed, measured in mph?), or torque into power, or energy into force or power, the beauty of the SI (metric) system really stands out. In the imperial system, the only way to get these calculations right is to insert all sorts of wacky numbers. Which you need to remember with potentially infinite precision.
Try this beauty: 1 Nm (Newton-meter) equals 1 J (Joule) equals 1 Ws (Watt-second). In the imperial system you'd have to insert all sorts of wacky numbers to go from pount-feet to calories to, strangely enough, Watt-seconds again. (Electricity, even in the US, is always measured in metric.)
Or more practical: Ever tried to convert the torque that your car engine delivers (measured in pound-feet) at a certain rpm (rounds per minute) to the horsepower (hp) that it delivers? In SI, it's a simple multiplication: Power (measured in W, or more commonly kW) = 2 * pi * torque (measured in Nm) * rotation speed (measured in 1/s). No wacky, imprecise numbers. Just 2 * pi due to the rotation and that's it.
The SI system and all the calculations you do with them are completely void of wacky numbers, with only a few exceptions:
- 2 times pi for anything that involves rotation.
- Natures constants like c (lightspeed), g (gravitational accelleration), e (elementry electric charge) and a few others, about half an A4 page full of them.
- Natural properties (like density) of materials that you use.
Since NASA does *a lot* of these calculations (how much force do you need to accelerate/decelerate the lunar lander, what's the effect of gravity?) I can understand why they switch to metric.
But if they were only going to do it half-assed (0.196850394-assed for metric folks),
I've always heard people talking about "a metric buttload" or "a metric assload" of this, that or the other thing. I never knew how much they were talking about, and I've been too embarassed to ask. Thank you for clearing up the conversion factor between a metric and imperial ass load!
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Yeah, right, so that would make it 1000 days in a year? And PI==10.0, I guess. The problem with imperial unit apologists is that they make such unreasonable arguments to try to justify an unreasonable system.
Now, let's get this straight, write it down carefully: the International System unit of time is the second. Minutes, hours, days, weeks, and months are ***NOT*** metric units
We have such weird units of time partly because neither the lunar month nor the solar day are exact divisors of the year and partly because of an old tradition on dividing the day. But, no matter how hours and minutes are counted, these are not part of the International System. You may buy eggs and beer cans by the dozen, but a kilogram is still a thousand grams.
I've grown up using Metric, since New Zealand's been standardised on it since well before I was born. I use it all the time, and I love it. So many different units of measurement go between each other in logical ways, many of which aren't noticed by most, right down to things like standard pencil widths being designed to match standard paper sizes. There are definitely problems with using it for day-to-day use, though, which I think most people just put up with. (The metre is often too big, the centimetre isn't big enough, and so on. Blocks of 10 cm would make a lot of sense, and I'm a bit surprised they don't get used.)
What imperial really has going for it, though, and one of the reasons it's so convenient, is that the units make it easier to divide things up for day-to-day tasks. In metric, it's easy to divide by 10, and often by 5 and 2, but outside of that the decimal places start getting long and often end up recurring. Dividing things into threes, fours and sixes really doesn't work if you also want twos and fives.
This is more to do with base 10 than with metric. I've often wondered if metric would be better long term if everyone counted in base 12, instead, and if the relationships between metric units were based on multiples of 12 instead of 10. For day to day use, simpler fractions translate to decimals (or whatever decimals are called in base 12) more nicely with base 12 than base 10. eg.
1/1 in base 10 is 1.0, in base 12 is 1.0.
1/2 in base 10 is 0.5, in base 12 is 0.6.
1/3 in base 10 is 0.333333..., in base 12 is 0.4.
1/4 in base 10 is 0.25, in base 12 is 0.3.
1/5 in base 10 is 0.2, in base 12 is 0.24.
1/6 in base 10 is 0.166666.... in base 12 is 0.2.
Base 12 makes the first 6 fractions easy to write as a decimal, whereas base 10 becomes a real problem. This probably wouldn't be practical because it's a huge learning curve for everyone, but it'd be quite interesting all the same.
You do realize, of course, that using metric units in no way stops you from using fractions rather than decimal whenever it is convenient?
You may use 3/4 cups of something; I'll use 1 1/2 dl. And one pint is a fairly good size for a beer, but then, so is 40cl, the normal size in Sweden. But of course we don't call it "40cl"; it's a "large beer".
If I estimate people's height, I'll just estimate to the nearest 5cm. That is a pretty convenient scale; fine enough to get close, and rough enough for me to have a good chance of being right.
Pretty much none of your arguments have anything to do with the units used, but with how you use them - and you can do it equally with either measurement system. As a guess, you have not had to use metric very much so you just have never built up a collection of mental tools equal to the one's you use for inches and stuff, and so you see it as clumsy and ill-fitting.
Trust the Computer. The Computer is your friend.
Q: So how are you going to implement this change to the metric system?
NASA: We will do it inch by inch.
Life is wet, then you dry.