Revise for precision

• Sloppy facts can also destroy things

• Review committees looking into what went wrong in outer space think the problem was confusion over units of measure. Engineers at NASA's Jet Propulsion Laboratory thought they were dealing in metric units -- or newtons per second -- when calculating spacecraft thrust, but the Lockheed Martin Corp. team that built the system had programmed the measurements in English pounds per second. The difference took the craft about 60 miles off course and into oblivion.