NASA's CONSTELLATION PROGRAM IS METRIC

摘要

In January 2007, NASA announced that it would use metric units for operations on the lunar surface (see Metric Today, March-April 2007). The organization later issued a Constellation Program Management Directive titled, "Use of SI as the Primary System of Measure for the Constellation Program, Projects, Systems, and Mission." NASA provided a copy of that internal document to USMA Webmaster Don Hillger. The Constellation Program, consisting of the Ares launch vehicle and Orion crew capsule, will eventually replace the space shuttle and, with the Altair Lunar Lander, explore the lunar surface. The aforementioned directive, issued on 19 December 2007, specifies as its purpose that "this directive establishes the International System of Units as the standard and default unit of measure of and throughout the Constellation Program (CXP). Narrow exceptions are defined where mixed use of English and SI units may be continued for legacy hardware, engineering, or fabrication."