The news article below, leads to a question about the current Eagle project as well as future AMSAT-NA projects.
All metric measurement based?
Greg. w9gb
=================================== NASA boldly goes with Metric System (SI) http://www.canada.com/montrealgazette/news/story.html?id=eca86baf-b80e-4941-...
TOM SPEARS, CanWest News Service Published: Friday, January 12, 2007
NASA has finally agreed to fly to the moon in metric - a move its scientists have wanted ever since they mixed up kilometres with miles and crashed an expensive spacecraft near Mars.
Space is an international business. And NASA says that only scientists of the United States, Myanmar and Liberia still measure distance in miles.
NASA's Vision for Space Exploration calls for returning astronauts to the moon by 2020 and eventually setting up a manned lunar outpost.
This week, the agency announced it will make the lunar project a metric-only job.
NASA quotes a senior moon mission manager, Jeff Volosin, as saying: "I think NASA has been seen as maybe a bit stubborn by other space agencies in the past, so this was important as a gesture of our willingness to be co-operative when it comes to the moon."
The change, announced after talks with space agencies from Canada and 14 other nations, could leave any space experts in Myanmar and Liberia on their own. Canada, however, seems pleased.
"Space engineering is tough enough without continuously having to remember all the conversion factors between various units," said Ben Quine, a professor of space engineering at York University.
"So it's good news that they're joining us, and good news for international collaboration.
"All of our courses are taught in SI (metric measure, abbreviated from the French Systeme international) so it will make it easier for our graduates to get jobs south of the border."
A probe called Mars Climate Orbiter reached Mars in 1999, but entered far too low in orbit and crashed on its first loop around the planet's far side. NASA later said its engineers had messed up a conversion of orbital information from metric to imperial units.
NASA started using metric measurements in some operations in 1990, but much of its work - such as aspects of shuttle missions and the International Space Station - continues in miles, pounds and gallons.
"My favorite imperial unit is the slug. The launch force of the shuttle is measured in slugs," Quine said. (The slug is defined as the mass that receives an acceleration of one foot per second per second when a force of one pound is applied to it.)
Making the change won't be easy for the Americans, he noted.
"Everybody has to be careful with their units when they convert." But he says it will make calculations easier in the long run. Everything fits together by tens, hundreds and so on.
"The foot was based on the size of the foot of one of the kings of England. I can't remember which one it is now. That's no way to run a space program, based on the size of a dead king's foot."
G. Beat wrote:
The news article below, leads to a question about the current Eagle project as well as future AMSAT-NA projects.
All metric measurement based?
Greg. w9gb
=================================== NASA boldly goes with Metric System (SI) http://www.canada.com/montrealgazette/news/story.html?id=eca86baf-b80e-4941-...
About $%&* time!
Now if we could only get the rest of the country to abandon our idiotic system of measure.
On 20 Jan 2007 at 10:18, G. Beat wrote:
"Everybody has to be careful with their units when they convert." But he says it will make calculations easier in the long run. Everything fits together by tens, hundreds and so on.
Here is an excerpt on the Canadian metric conversion experience. Still today we tend to convert to the old english system (old generation) but the new generation are fully imbedded in the SI system.
The harder part is the temperature system and the volume measures. A big plus it is a decimal based system no more 1/64 1/32 and so on odd fraction. As in Asterix a small village still resist the conversion...
I remember the advertisement campaign at that time "don't convert think metric" easier to say than doing.
Here is the excerpt.
Metric Conversion is the process of making metric units, eg, metre (m), litre (L), kilogram (kg), degree Celsius (°C), the common units of measurement in Canada. Although the metric system was legalized in Canada in 1871, the British imperial system of units, based on yards, pounds, gallons, etc, continued to predominate. In the 1960s, with rapidly advancing technology and expanding worldwide trade, the need for an international measurement system became increasingly apparent. Britain decided to convert to the metric system and the US was studying a similar move.
A number of Canadian associations representing diverse interests, including consumers, educators and professionals, made representations to the government favouring the metric system. In January 1970 the White Paper on Metric Conversion in Canada set out Canadian government policy. It stated that a single, coherent measurement system based on metric units should be used for all measurement purposes, including legislation. In line with this policy, the Weights and Measures Act was amended by Parliament in 1971 to recognize the Système International d'Unités (SI), the latest evolution of the metric system, for use in Canada. Also in 1971, Parliament passed the Consumer Packaging and Labelling Act, requiring that metric units be shown on labels of most consumer products.
To implement metric conversion the government established a Preparatory Commission in 1971, later called Metric Commission Canada. The commission's role was to ensure a planned and co-ordinated conversion in all sectors of the Canadian economy and to disseminate information on metric conversion. Beginning in 1973 the commission organized over 100 sector committees, with members from national associations and major organizations representing business and industry, consumers, labour, health, education and government. Each sector committee was responsible for preparing a sector conversion plan and monitoring its implementation. The commission as a whole approved sector conversion plans developed through consensus.
The process of replacing imperial units with SI units in all kinds of documents, measuring devices, manufacturing processes, products and packages involved a countless variety of tasks. The technical basis for the change to SI units was established by 2 national standards of Canada, the International System of Units (SI) and the Canadian Metric Practice Guide, first published in 1973 by the Canadian Standards Association and approved by the Standards Council of Canada.
After choosing appropriate SI units, practical approaches to implementation were debated by sector committees, with each sector determining policies and strategies to suit its interests. Soft conversion (arithmetical conversion of pre-existing measurement values) versus hard conversion (round, rational values in metric units, possibly requiring physical change in product size) was a major issue. The use of both imperial and metric measurements was another area of controversy. Dependence on the US for many parts and products was a constraint for many sectors. The dedicated efforts of Canadian industry allowed conversion to proceed with few major problems, although it took 2-5 years longer than planned.
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe WAC BASIC CW PHONE SATELLITE
At 06:48 AM 1/21/2007, you wrote:
Here is an excerpt on the Canadian metric conversion experience. Still today we tend to convert to the old english system (old generation) but the new generation are fully imbedded in the SI system.
Conversion was pretty painless in Australia. I recall the latter years of dual measurements, just before we went metric only. Nowadays, everyone uses metric for weather related parameters, temperature, wind speed, pressure. For everyday use, most people use metric or a mix of metric and the older units in everyday conversation. I am well versed in both systems, because of the time I grew up with and a natural aptitude for dealing with different measurements, and these days, I can do a lot of common conversions in real time in my head (as reasonably close approximations).
The harder part is the temperature system and the volume measures. A big plus it is a decimal based system no more 1/64 1/32 and so on odd fraction. As in Asterix a small village still resist the conversion...
Temperature seemed to be easier here, one rarely hears anyone use Farenheit here. Volume has some lingering artefacts (e.g. people still speak of "44 gallon drums", not "205 litre drums").
I remember the advertisement campaign at that time "don't convert think metric" easier to say than doing.
I can still think in terms of either system directly, without having to convert. :)
In any case, when it comes to mathematical purposes, SI units are much easier to deal with - less oddball constants that have to be thrown into equations. I'm glad my university days were long after conversion to SI here. :-) And the speed of light happens to be a much nicer constant to work with (for calculating propagation delays and wavelengths). 300,000,000 m/s is much easier than 186,000 miles/sec for quick mental calculations! ;)
73 de VK3JED http://vkradio.com
Metric, What is the equivelent of Board Feet of Lumber? Threads per inch or mm OK, but why this pitch stuff?
Anyone got metric back gears for my WW II South Bend lathe ? Don't suggest some made in China junk with a AC motor. Think the US Goverment is going to give me a new one to be metric? Dream on!
A minute is a Nautical Mile (6000) feet in latitude. ( 100 feet per second) Latitude times the COS of the latitude for longitude. (At 33N = 1 second of longitude = 84 feet) Try that in kilometers! Guess your GPS will do those things for you. FYI: A grid square is only square at 60 degrees of latitude. COS = 0.5
On the other hand many caculations are simplified with metrics, wavelength for example. Amps, Volts, Farrads, Henerys, Ohms, Frequency, and Watts are same in metric and need no conversion.Grams, Litres and Meters require developing a feel. I can visualize an inch, not 3 cm ? I can feel an ounce, but not a gram, besides a pint is a pound of water! Is a litre of water a Kilogram?
Logic is often only in the eyes of the beholder! Easy is only in the the skill and knowledge of the craftsman!
Art,
KC6UQH
----- Original Message ----- From: "Tony Langdon" vk3jed@gmail.com To: amsat-bb@amsat.org Sent: Saturday, January 20, 2007 6:16 PM Subject: [amsat-bb] Re: AMSAT-NA totally metric?
At 06:48 AM 1/21/2007, you wrote:
Here is an excerpt on the Canadian metric conversion experience. Still today we tend to convert to the old english system (old generation) but the new generation are fully imbedded in the SI system.
Conversion was pretty painless in Australia. I recall the latter years of dual measurements, just before we went metric only. Nowadays, everyone uses metric for weather related parameters, temperature, wind speed, pressure. For everyday use, most people use metric or a mix of metric and the older units in everyday conversation. I am well versed in both systems, because of the time I grew up with and a natural aptitude for dealing with different measurements, and these days, I can do a lot of common conversions in real time in my head (as reasonably close approximations).
The harder part is the temperature system and the volume measures. A big plus it is a decimal based system no more 1/64 1/32 and so on odd fraction. As in Asterix a small village still resist the conversion...
Temperature seemed to be easier here, one rarely hears anyone use Farenheit here. Volume has some lingering artefacts (e.g. people still speak of "44 gallon drums", not "205 litre drums").
I remember the advertisement campaign at that time "don't convert think metric" easier to say than doing.
I can still think in terms of either system directly, without having to convert. :)
In any case, when it comes to mathematical purposes, SI units are much easier to deal with - less oddball constants that have to be thrown into equations. I'm glad my university days were long after conversion to SI here. :-) And the speed of light happens to be a much nicer constant to work with (for calculating propagation delays and wavelengths). 300,000,000 m/s is much easier than 186,000 miles/sec for quick mental calculations! ;)
73 de VK3JED http://vkradio.com
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
At 07:20 21/01/2007, you wrote:
Metric, What is the equivelent of Board Feet of Lumber? Threads per inch or mm OK, but why this pitch stuff?
besides a pint is a pound of water! Is a litre of water a Kilogram?
Yes.. ! 1 litre of water is 1 Kilogram, in fact the entire metric weight system is based on this. 1000 Litres of water is 1 metric Tonne, (1000 Kg ) 1 ml of water is 1 gram. Plus the bonus of working in decimal points rather than fractions.
Metric, What is the equivelent of Board Feet of Lumber? Threads per inch or mm OK, but why this pitch stuff?
besides a pint is a pound of water! Is a litre of water a Kilogram?
Pint? Do you mean a US pint (16 US fluid ounces = 480 ml)or an Imperial pint (20 Imperial fluid ounces = little over 568 ml). Perhaps you meant an Australian pint (of beer) at 570 ml, or maybe an South Australian pint (again of beer) at a measly 425 ml.
Sil
A minute is a Nautical Mile (6000) feet in latitude. ( 100 feet per second) Latitude times the COS of the latitude for longitude. (At 33N = 1 second of longitude = 84 feet) Try that in kilometers! Guess your GPS will do those things for you. FYI: A grid square is only square at 60 degrees of latitude. COS = 0.5
And who on this side of the planer is at 60 degrees? Maybe a few seals and whales LOL Conversion between degrees and distance is not required much these days, with GPS and good maps. Nautical measurements are still used here in any case, in meteorology for example (wind speed is in km/h and knots).
On the other hand many caculations are simplified with metrics, wavelength for example. Amps, Volts, Farrads, Henerys, Ohms, Frequency, and Watts are same in metric and need no conversion.Grams, Litres and Meters require developing a feel. I can visualize an inch, not 3 cm ? I can feel an ounce, but not a gram, besides a pint is a pound of water! Is a litre of water a Kilogram?
3cm, dat's a little less than 1 1/4" ;) And a litre of water has 1kg mass (at 4 degrees Centigrade - the temperature at which the density of water is maximum).
73 de VK3JED http://vkradio.com
At 09:03 PM 1/21/2007 +1100, Tony Langdon wrote:
And who on this side of the planer is at 60 degrees? Maybe a few seals and whales LOL Conversion between degrees and distance is not required much these days, with GPS and good maps. Nautical measurements are still used here in any case, in meteorology for example (wind speed is in km/h and knots).
I am (lat 60.675)...so there :-) If you meant lat -60, well you win, 73's, Ed - KL7UW ========================================= BP40iq, Nikiski, AK http://www.qsl.net/al7eb Amsat #3212 Modes: V - U - L - S USA Rep. for Dubus Magazine: dubususa@hotmail.com =========================================
Anyone got metric back gears for my WW II South Bend lathe ? Don't suggest some made in China junk with a AC motor. Think the US Goverment is going to give me a new one to be metric? Dream on!
Most of the folks doing production machine shop stuff have long since gone CNC, and I know CNC mills can handle most common engineering units including metric. Lathes, most of what's out there now is "made in China" gearhead stuff that is designed primarly to be metric and handles English units as sort of an afterthought.
(That being said, I've worked with a South Bend myself and fell in love with it from the first cut, and the fact that the old WWII era South Bend lathes don't do metric threads is worth putting up with for the sheer joy of making stuff on them. Especially with a good solid toolpost. :D )
Logic is often only in the eyes of the beholder! Easy is only in the the skill and knowledge of the craftsman!
You've made an important point, and that's that what you grew up with and what your eyes and hands "know" intuitively is hard to relearn in other units. I was exposed to metric *very* early in my life (was in elementary school when metric was all the rage in the schools) and picked it up sort of intuitively, but had to relearn into English units for the one-off custom machine shop work I was doing for a job several years ago. There are some aspects of the machinist's art in this country that will be very difficult to convert into metric for some time to come. (I can tell part fits and clearances to about . 001" by feel. I have no idea what the equivalent in metric is without getting out a calculator. That's only one of many examples.) It'll probably happen, but it's going to take quite some time, at least here .. and something will be lost in the translation ..
"There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey." -- John Ruskin
From an earlier posting:
"My favorite imperial unit is the slug. The launch force of the shuttle is measured in slugs," Quine said. (The slug is defined as the mass that receives an acceleration of one foot per second per second when a force of one pound is applied to it.)
Yikes! While the *mass* of the shuttle might be measured in slugs, the force of its rockets will be measured in pounds.
It's so much easier in metric, where a kilogram is very much a unit of mass, while force is measured in newtons...and let's not worry about ergs and dynes and things: SI is mks.
Laura Halliday VE7LDH "Que les nuages soient notre Grid: CN89mg pied a terre..." ICBM: 49 16.05 N 122 56.92 W - Hospital/Shafte
_________________________________________________________________ Achetez ce que vous voulez, quand vous voulez sur Sympatico / MSN Magasiner http://magasiner.sympatico.msn.ca/content/shp/?ctId=101,ptnrid=176,ptnrdata=...
Speaking of energy .. one thing I wish would come into common usage, because I've found it really handy for comparison purposes, is expressing energy in joules (one of my favorite SI units), because it's both a newton-meter of work (not a newton-meter of torque! :) and a watt-second of energy. Outside the scientific community, energy is referred to as everything from BTU (heating/cooling) to gallons of gasoline (automotive) to tons of TNT (nuclear weapons) to foot-pounds of work (ballistics), it's enough to make an empirical skilled generalist's head spin. (And I know I'm not the only one of those.)
And yes, a liter of water is a kilogram, by definition, since the gram was originally defined (IIRC) as the mass of a cubic centimeter (i.e. milliliter) of water. (The kilogram is one of the few units still referenced to a physical standard object kept at the International Bureau of Weights and Measures, interestingly enough. The meter used to be referenced to a standard meter bar kept at the same bureau, but has now been defined by a quantum standard that doesn't require reference to a physical object.)
On Jan 20, 2007, at 11:02 PM, laura halliday wrote:
It's so much easier in metric, where a kilogram is very much a unit of mass, while force is measured in newtons...and let's not worry about ergs and dynes and things: SI is mks.
ENGLISH: A language that lurks in dark alleys, beats up other languages, and rifles through their pockets for spare vocabulary.
participants (10)
-
Bruce Bostwick -
Edward R. Cole -
G. Beat -
Jim Walls -
John Wright -
kc6uqh -
laura halliday -
Luc Leblanc -
Sil - ZL2CIA -
Tony Langdon