by neufer » Sun Nov 04, 2012 5:39 pm
APOD Robot wrote:
On some days the city of
Seattle,
Washington,
USA, is treated to an unusual sky show when
lenticular clouds form near
Mt. Rainier, a large mountain that looms just under 100 kilometers southeast of the city.
Kudos to an APOD that actually neglected (
) to translate kilometers into miles.
http://en.wikipedia.org/wiki/Metrication#Accidents_and_incidents wrote:
<<Confusion over units during the process of metrication can sometimes lead to accidents. One of the most famous examples was during Canada's metrication: in 1983, an Air Canada Boeing 767, nicknamed the "
Gimli Glider" after the incident, ran out of fuel in mid-flight. The incident was caused, in a large part, by the confusion over the conversion among litres, kilograms, and pounds, resulting in the aircraft receiving 22,300 pounds of fuel instead of the required 22,300 kg.
On 25 September 2009, the British Department for Transport published a draft version of legislation to amend its road signage legislation for comment. Amongst the proposed changes is an amendment to existing legislation to make dual unit height and width warning and restriction signs mandatory. This is justified in Paragraph 53 of the Impact Analysis by the text "... Based on records from Network Rail's incident logs since April 2008, approximately 10 – 12% of bridge strikes involved foreign lorries. This is disproportionately high in terms of the number of foreign lorries on the road network." This proposal was shelved with the change of government in 2010, though many bridges are now dual signed.
Only the United States continues to see significant popular opposition to metrication, the main objections being based in localism, tradition, cultural aesthetics, economic impact, or distaste for measures viewed as "foreign". Japan had significant popular opposition at one time for similar reasons. Popular opposition in the United Kingdom exists to a lesser degree and can be associated with anti-European Union sentiment. France, where the measures were largely invented, saw popular opposition during the early 19th century, though not for long. Thus, with the exception of the United States, metrication is now fully or substantially accepted in all countries.>>
How many ages hence shall this our lofty scene be acted over in states unborn and accents yet unknown!
- - - CASSIUS, Julius Caesar Act 3, Scene 1
http://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_failure wrote:
<<The Mars Climate Orbiter (formerly the Mars Surveyor '98 Orbiter) was a 338 kilogram (750 lb) robotic space probe launched by NASA on December 11, 1998 to study the Martian climate, atmosphere, surface changes and to act as the communications relay in the Mars Surveyor '98 program, for Mars Polar Lander. However, on September 23, 1999, communication with the spacecraft was lost as the spacecraft went into orbital insertion.
On November 10, 1999, the Mars Climate Orbiter Mishap Investigation Board released a Phase I report, detailing the suspected issues encountered with the loss of the spacecraft. Previously, on September 8, 1999,
Trajectory Correction Maneuver-4 was computed and then executed on September 15, 1999. It was intended to place the spacecraft at an optimal position for an orbital insertion maneuver that would bring the spacecraft around Mars at an altitude of 226 kilometers on September 23, 1999. However, during the week between TCM-4 and the orbital insertion maneuver, the navigation team indicated the altitude may be much lower than intended at 150 to 170 kilometers. Twenty-four hours prior to orbital insertion, calculations placed the orbiter at an altitude of 110 kilometers; 80 kilometers is the minimum altitude that Mars Climate Orbiter was thought to be capable of surviving during this maneuver. Final calculations placed the spacecraft in a trajectory that would have taken the orbiter within 57 kilometers of the surface where the spacecraft likely disintegrated because of atmospheric stresses. The primary cause of this discrepancy was engineering error.
Specifically, the flight system software on the Mars Climate Orbiter was written to take thrust instructions using the metric unit newtons (N), while the software on the ground that generated those instructions used the Imperial measure pound-force (lbf). This error has since been known as the metric mixup and has been carefully avoided in all missions since by NASA.
The discrepancy between calculated and measured position, resulting in the discrepancy between desired and actual orbit insertion altitude, had been noticed earlier by at least two navigators, whose concerns were dismissed. A meeting of trajectory software engineers, trajectory software operators (navigators), propulsion engineers, and managers, was convened to consider the possibility of executing TCM-5, which was in the schedule. Attendees of the meeting recall an agreement to conduct TCM-5, but it was ultimately not done.>>
[quote="APOD Robot"]
On some days the city of [url=http://en.wikipedia.org/wiki/Seattle]Seattle[/url], [url=http://en.wikipedia.org/wiki/Washington_%28state%29]Washington[/url], [url=http://en.wikipedia.org/wiki/United_States]USA[/url], is treated to an unusual sky show when
lenticular clouds form near [url=http://en.wikipedia.org/wiki/Mt._Rainer]Mt. Rainier[/url], a large mountain that looms just under 100 kilometers southeast of the city.[/quote]
[c]Kudos to an APOD that actually neglected ( :?: ) to translate kilometers into miles.[/c]
[quote=" http://en.wikipedia.org/wiki/Metrication#Accidents_and_incidents"]
[float=right][img3="[b][color=#0000FF]the "Gimli Glider"[/color][/b]"]http://upload.wikimedia.org/wikipedia/en/2/24/Gimli_glider.JPG[/img3][/float]
<<Confusion over units during the process of metrication can sometimes lead to accidents. One of the most famous examples was during Canada's metrication: in 1983, an Air Canada Boeing 767, nicknamed the "[url=http://en.wikipedia.org/wiki/Gimli_Glider]Gimli Glider[/url]" after the incident, ran out of fuel in mid-flight. The incident was caused, in a large part, by the confusion over the conversion among litres, kilograms, and pounds, resulting in the aircraft receiving 22,300 pounds of fuel instead of the required 22,300 kg.
On 25 September 2009, the British Department for Transport published a draft version of legislation to amend its road signage legislation for comment. Amongst the proposed changes is an amendment to existing legislation to make dual unit height and width warning and restriction signs mandatory. This is justified in Paragraph 53 of the Impact Analysis by the text "... Based on records from Network Rail's incident logs since April 2008, approximately 10 – 12% of bridge strikes involved foreign lorries. This is disproportionately high in terms of the number of foreign lorries on the road network." This proposal was shelved with the change of government in 2010, though many bridges are now dual signed.
Only the United States continues to see significant popular opposition to metrication, the main objections being based in localism, tradition, cultural aesthetics, economic impact, or distaste for measures viewed as "foreign". Japan had significant popular opposition at one time for similar reasons. Popular opposition in the United Kingdom exists to a lesser degree and can be associated with anti-European Union sentiment. France, where the measures were largely invented, saw popular opposition during the early 19th century, though not for long. Thus, with the exception of the United States, metrication is now fully or substantially accepted in all countries.>>[/quote]
[b][i][color=#0000FF]How many ages hence shall this our lofty scene be acted over in states unborn and accents yet unknown![/color][/i][/b]
[list]- - CASSIUS, Julius Caesar Act 3, Scene 1[/list]
[quote=" http://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_failure"]
[float=right][img3=""]http://upload.wikimedia.org/wikipedia/commons/thumb/1/19/Mars_Climate_Orbiter_2.jpg/528px-Mars_Climate_Orbiter_2.jpg[/img3][/float]
<<The Mars Climate Orbiter (formerly the Mars Surveyor '98 Orbiter) was a 338 kilogram (750 lb) robotic space probe launched by NASA on December 11, 1998 to study the Martian climate, atmosphere, surface changes and to act as the communications relay in the Mars Surveyor '98 program, for Mars Polar Lander. However, on September 23, 1999, communication with the spacecraft was lost as the spacecraft went into orbital insertion.
On November 10, 1999, the Mars Climate Orbiter Mishap Investigation Board released a Phase I report, detailing the suspected issues encountered with the loss of the spacecraft. Previously, on September 8, 1999, [b][color=#0000FF]Trajectory Correction Maneuver-4 was computed and then executed on September 15, 1999[/color][/b]. It was intended to place the spacecraft at an optimal position for an orbital insertion maneuver that would bring the spacecraft around Mars at an altitude of 226 kilometers on September 23, 1999. However, during the week between TCM-4 and the orbital insertion maneuver, the navigation team indicated the altitude may be much lower than intended at 150 to 170 kilometers. Twenty-four hours prior to orbital insertion, calculations placed the orbiter at an altitude of 110 kilometers; 80 kilometers is the minimum altitude that Mars Climate Orbiter was thought to be capable of surviving during this maneuver. Final calculations placed the spacecraft in a trajectory that would have taken the orbiter within 57 kilometers of the surface where the spacecraft likely disintegrated because of atmospheric stresses. The primary cause of this discrepancy was engineering error. [b][color=#FF00FF]Specifically, the flight system software on the Mars Climate Orbiter was written to take thrust instructions using the metric unit newtons (N), while the software on the ground that generated those instructions used the Imperial measure pound-force (lbf). This error has since been known as the metric mixup and has been carefully avoided in all missions since by NASA.[/color][/b]
[b][color=#FF0000]The discrepancy between calculated and measured position, resulting in the discrepancy between desired and actual orbit insertion altitude,[u] had been noticed earlier by at least two navigators, whose concerns were dismissed[/u]. A meeting of trajectory software engineers, trajectory software operators (navigators), propulsion engineers, and managers, was convened to consider the possibility of executing TCM-5, which was in the schedule. Attendees of the meeting recall an agreement to conduct TCM-5, but it was ultimately not done.[/color][/b]>>[/quote]