August 10, 2005: Have you ever walked across a wool carpet in
leather-soled shoes on a dry winter day, and then reached out
toward a doorknob? ZAP! A stinging spark leaps between your
fingers and the metal knob. That's static discharge--lightning
writ small. Static discharge is merely annoying to anyone on
Earth living where winters have exceptionally low humidity. But
to astronauts on the Moon or on Mars, static discharge could be
real trouble. Right: Beware the door knob. [More] "On Mars, we
think the soil is so dry and insulating that if an astronaut
were out walking, once he or she returned to the habitat and
reached out to open the airlock, a little lightning bolt might
zap critical electronics," explains Geoffrey A. Landis, a
physicist with the Photovoltaics and Space Environmental Effects
Branch at NASA Glenn Research Center in Cleveland, Ohio. This
phenomenon is called triboelectric charging. The prefix "tribo"
(pronounced TRY-bo) means "rubbing." When certain pairs of
unlike materials, such as wool a