NASA Gets Heat For Ditching Metric System on New Shuttle Replacement, Popular Science
"The commercial spaceflight sector, who had hoped to use the Orion and Ares systems for a variety of missions, is not too happy. "We in the private sector are doing everything possible to create a global market with as much commonality and interoperability as possible. But NASA still can't make the jump to metric." Mike Gold of Bigelow Aerospace told New Scientist."
NASA Inspector General's Assessment of NASA's Use of the Metric System, G-00-021 (2001)
"As the United States continues its slow transition to the metric system, NASA must decide whether it wants to be a leader or a follower in the transition process. Both roles come with a cost. If NASA chooses to push forward with the Agency's use of the metric system, near-term costs may increase and short-term risk (both to schedule and mission success) may rise to some degree. However, if the Agency follows the aerospace industry's slow transition to SI, the protracted period during which NASA uses mixed metric and English systems may further increase costs and risks for NASA programs."
NASA Finds The Metric System Too Hard To Implement for Constellation, Earlier Post
"NASA claims that it wants to have meaningful international participation in the implementation of VSE/ESAS yet it walks away from the system of weights and measures used by the majority of the people on this planet. Moreover, this decision clearly seems to fly in the face of established NASA - and Federal - policy."
NASA criticised for sticking to imperial units, New Scientist
"NASA recently calculated that converting the relevant drawings, software and documentation to the "International System" of units (SI) would cost a total of $370 million almost half the cost of a 2009 shuttle launch, which costs a total of $759 million. "We found the cost of converting to SI would exceed what we can afford," says Hautaluoma."
Keith's note: That's a goofy answer. Why couldn't ESMD have simply directed that things be done in metric in the first place - in compliance with NASA's own regulations (note the OIG report from 2001 years before Constellation was even started). That way there'd be no "conversion" cost.
Oh yea, interesting how Grey just told us what a shuttle launch "costs".