posted 04-04-2007 11:24 AM               

What you see in books like Moonport was the result of the early 1970s push in the U.S. to convert to the metric system. As usual, the government felt it was its job to lead the way and, if I recall correctly, mandated at least the inclusion of both units in its documents, if not a full conversion to metric. You can even catch the occasional NASA tech report from that period with diclaimers related to use of metric/english. We all know how the US conversion to metric worked out.

Hope this helps,

posted 04-04-2007 06:04 PM            

The 'screen captures' in the appendix of Sy's book leaves little doubt that telemetry data was also English- PSIA and degrees F, e.g.

posted 04-06-2007 09:24 AM               

Further, regarding the use of the Metric System during earlier NASA programs, it really came into prominence during the days of Skylab and ASTP. Examination of some NASA publications of that day, such as the "Mission Reports"-series, show a definite transition over to the Metric world.

This was coincident with the Federal government's push to use Metric measurement during the mid-1970s.

posted 04-23-2007 03:48 PM               

Regards,

posted 06-18-2007 07:33 AM            

quote:

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Originally posted by kr4mula:

What you see in books like Moonport was the result of the early 1970s push in the U.S. to convert to the metric system. As usual, the government felt it was its job to lead the way and, if I recall correctly, mandated at least the inclusion of both units in its documents, if not a full conversion to metric.

Kevin

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You are correct--all those NASA Histories dating from the '70s onward all use metric units because it was a government mandate. An ill-conceived one, I might add. It is very annoying to have to mentally convert kilometers or kilograms or newtons to English measurements while reading Stages to Saturn, for example.

I don't have the Mercury NASA History in front of me here (This New Ocean) but I'm wondering if it has metric units or if it was published before the 1970s GPO mandated metric push.

If God had intended for us to use metric measurements, He would have had ten apostles, not twelve.

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tfrielin

posted 06-18-2007 11:50 AM               

The switch is definitely annoying for us writing across programs and having to deal with the conversion mid-way through our subjects. It's even worse for measurements with multiple units (e.g. pressure, with psi, mmHg, Atm, etc.).

Cheers,

posted 06-18-2007 09:41 PM               

Almost as ridiculous as using a TV system that has 100 more lines of vertical resolution, and which employs phase correction to ensure the colours stay the same.

posted 06-20-2007 11:13 AM               

Cheers,

posted 06-20-2007 11:46 AM               

For instance, I recall being told as a child that a foot was the length of some King's foot in ancient history, and a yard was the distance from the above King's nose to the thumb of his outstretched arm.

Later on when I studied navigation I learned that a nautical mile is based on a minute of arc along a meridian of the Earth.

While all of these source units are subjective based on the size of the King or even the size of the planet you happen to be standing on, at least there is some reasoning behind it.

I was just curious if there was something similar used for the root of the metric system?

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Kind Regards

Douglas Henry

posted 06-20-2007 02:21 PM               

quote:

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Originally posted by Aztecdoug:
I am curious about the source, or base unit, used for the metric system. Is there one?

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Wow... I answered my own question here. Wikipedia is great... I found that the meter, or the base unit of the metric system may have evolved over time.

1790 May 8 — The French National Assembly decides that the length of the new metre would be equal to the length of a pendulum with a half-period of one second.

1791 March 30 — The French National assembly accepts the proposal by the French Academy of Sciences that the new definition for the metre be equal to one ten-millionth of the length of the Earth's meridian along a quadrant through Paris, that is the distance from the equator to the north pole.

1799 December 10 — The French National Assembly specifies the platinum metre bar, constructed on 23 June 1799 and deposited in the National Archives, as the final standard.

1983 October 21 — The seventeenth General Conference on Weights and Measures (CGPM) defines the length as equal to the distance travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

Funny, based on the March 1791 change, it appears that the meter may in some respects be a cousin to the nautical mile. 1n.m. = 1852 meters.

I think we will have to convert to some atomic based unit of measure when we make peace with other aliens from outer space. Otherwise our joint venture probes may crash into planets in other galaxies.

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Kind Regards

Douglas Henry

posted 06-21-2007 12:32 PM               

Cheers,

Kevin