J. Ward, Is all of this for real? In the USA? Are you sure that American companies are using that much metric? Or is it metric because it may be imported from elsewhere?
Jerry ________________________________ From: J. Ward <[email protected]> To: U.S. Metric Association <[email protected]> Cc: U.S. Metric Association <[email protected]> Sent: Thursday, January 22, 2009 9:27:43 PM Subject: [USMA:42412] NASA and the metric system Pat Naughtin wrote: > 2 Nasa designs builds and flies spacecraft using metric units for measurement > and then reports their successes or failures in old pre-metric measures for > the public. Hi Pat, That's not quite right. The Jet Propulsion Laboratory (which is part of the California Institute of Technology, with contracts with NASA) works mostly in metric units. Spacecraft components are specified in millimeters and grams. The large majority of detailed drawings are in millimeters typically on ISO size A1 sheets. Epoxies are weighed out in grams and cured in ovens measured in degrees Celsius. Distances in the solar system, including rover operations on Mars, are typically measured in metric units. Most fasteners are metric sizes. Environmental scientists measure atmospheric pressure in hPa, which I might add is a very convenient unit for this purpose. A variety of non-SI units are in common use at JPL, such as measuring vacuum pressures in Torr, or astronomers measuring in parsecs and solar masses. NASA headquarters, on the other hand, and most of the manned space program, are the opposite. I was at a meeting last week where several senior managers and astronauts from NASA headquarters gave presentations. Altitudes were specified in feet, speed in miles per hour, pressures in PSI, etc. However, one speaker from NASA headquarters used almost exclusively SI units. He is a Nobel laureate. J.
