If you are thinking of visiting the moon, you will now need to take only one set of spanners. (News item reported by two UK Metric Association members).
The United States National Aeronautics and Space Administration (NASA) announced on 8 January 2007 that it has decided to use metric units for all operations on the lunar surface when it returns to the moon. For more details, see: http://science.nasa.gov/headlines/y2007/08jan_metricmoon.htm?list864576
Two centuries ago, the founding fathers of the metric system had a vision of a system that was simple, rational and universal. Little could they realise that ‘universal’ would one day extend beyond our planet.