On Saturday afternoon, NASA astronauts Chris Cassidy and Tom Marshburn successfully completed a spacewalk to repair a leaky component on the outside of the International Space Station.

FORBES: Astronauts Perform Emergency Spacewalk To Fix Ammonia Leak

At Cornell University, researchers are experimenting with using 3D printers to print food that could be eaten by astronauts in space, and scientists in Edinburgh successfully 3D-printed embryonic stem cells for the first time, demonstrating how 3D-printing technology could one day eliminate the need for organ donation.

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But first, two NASA astronauts successfully completed a space walk today and removed two troubling pieces of ceramic fabric sticking out from the Discovery Shuttle's heat shield.

NPR: Shuttle Spacewalk Repair Mission a Success