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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 /.
I was under the impression that most scientific agencies used metric as a standard (Guess US educational system failed me there). My father is a builder and I grew up seeing how contractors can be so loose with measurements. It amazes me that NASA got this far using a very inaccurate system (at times) for such precise operations.
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.
recruited a 2.1336 meter guy
You use 3 significant figures in the imperial system when you say 7'11". Why do you feel you have to use 5 significant figures in the metric system? 2.13 m is good enough. It's not that hard really.
Seven puppies were harmed during the making of this post.
Note that you don't see any movements to "bring back the imperial system" elswhere in the world, because metric *works*.
I run: Windows, OS X, Linux, FreeBSD. Just because you have a hammer, doesn't mean everything is a nail.
Sounds to me like you have a problem with the official report, not Wikipedia.
Wikipedia places a high level of importance on citations. Were you able to come up with credible citations to backup your alternate conclusions? If not, you should start a "NASA MCO Conspiracy" page on MySpace instead editing the Wikipedia topic.
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.
In my experience, most Americans under 30 can't even convert from miles to yards. Yes all systems of units are arbitrary conventions, but some of them are better designed than others. You don't need a calculator to find out how many centimeters are there in 174.56 m. That makes it particularly well suited for every day use. By the way, the eV is as much of a metric system unit as the degree Celsius. See this.
"You can't allow somebody to commit the crime before you detain them." [Condoleezza Rice]
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.
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.
I wish Americans would stop calling them "English" units. Not only are they no longer generally used in England (with the odd exception like pints of beer and miles) but the even when they were used they were different from the American system. For example there are 20 fluid ounces in an Imperial pint vs. 16 fluid ounces in a US pint....so it is a very good thing than NASA is no longer using them for international missions since there isn't even an Imperial standard that anyone can agree on!
"Err...Houston we may have a problem, when you told us to burn 10 pints of fuel was that Imperial pints or US pints?"
"You do realize, of course, that using metric units in no way stops you from using fractions rather than decimal whenever it is convenient?"
Actually, it does because ten has less factors (1,2,5,10) than twelve (1,2,3,4,6,12) or sixteen (1,2,4,8,16).
Huh? What stops you from counting in whatever fractions you're comfortable with? If you want to use 4 3/12 deciliters or something, just go ahead.
If I take a stick that's 1 foot long and cut it into four pieces, I have four sticks that are 3 inches long. If I take a stick that's one meter long and cut it into four pieces, I have four sticks that are 25 centimeters long.
You have four stick of 1/4 meter each. If you take one meter and cut into five pieces you get five sticks of 2dm. What does cutting a one foot stick in five pieces get you?
I think you need to calm down a bit; you're sounding quite obsessive about this, to the point of being irrational.
Trust the Computer. The Computer is your friend.