NASA to shift gear in shock discovery

NASA is to replace braking mechanisms on all its space shuttles in a bid to avert another catastrophe after discovering some of the gears were installed backwards.

Shuttle programme manager Bill Parsons launched an investigation into why the rudder speed brake gears all old original parts in the shuttle tails were never inspected in more than two decades of flight. If one of the improperly installed gears had been in a high-stress position, it would probably have led to the spacecraft's destruction at touchdown, he said.

"Bottom line is, it was not good," Mr Parsons said.