2 Teachers Make Mission's Final Walk

Two astronauts who were teaching math and science to middle school students just 5 years ago went on a spacewalk together today, their path cleared of dangerous orbiting junk that had threatened the space station and shuttle. It's the first time two former schoolteachers have been on a spacewalk together, and is the third and final spacewalk for shuttle Discovery's mission.

Astronauts Joseph Acaba and Richard Arnold II had no luck trying to free up a jammed equipment storage shelf at the international space station, one of their main tasks. Using a hammer, they managed to loosen a pin that Acaba and another astronaut accidentally inserted upside down on the platform during Saturday's spacewalk. But the shelf mechanism would not extend into the proper position, despite repeated efforts. (More NASA stories.)