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Astronauts Piers Sellers and Mike Fossum took a third space walk on Wednesday to test procedures for emergency repairs. The two took infrared video to see if damage within the shuttle's reinforced carbon panels could be detected.
Applying sealant with putty knife
The space shuttle brought damaged panels to see if astronauts could repair them in orbit using a substance called NOAX--a pre-ceramic polymer sealant containing carbon-silicon carbide powder. Their tools, a caulk gun and spatulas.
The weightless Discovery crew poses for a head-to-head photo shoot. From the bottom left are astronauts Stephanie Wilson; Steven Lindsey, commander; and Lisa Nowak. From the top left are astronauts Piers Sellers, Michael Fossum, and Mark Kelly.