STS-121 mission specialists Lisa Nowak and Mike Fossum talked to reporters with U.S. TV networks MSNBC and Fox News, and Fossum received a call from Texas Governor Rick Perry.

On Wednesday, mission specialists Piers Sellers and Mike Fossum began their third spacewalk at 7:20 a.m. Eastern Time by preparing a foot restraint on the end of the space station's Canadarm2.

Sellers rode the arm, commanded by mission specialists Lisa Nowak and Stephanie Wilson, to Discovery's starboard wing, where he used an infrared camera to shoot 20 seconds of video of selected reinforced carbon-carbon panels on the wing's leading edge.

NASA engineers think infrared imagery could help identify damage to the inside of those panels.

Fossum moved to the aft of Discovery's payload bay to join Sellers and help prepare a box containing 12 RCC sample panels for their primary task of testing a repair material called NOAX. Non-oxide adhesive experimental is a pre-ceramic polymer sealant containing carbon-silicon carbide powder. It is being evaluated for repairing damage to RCC panels.

Data gathered from tests on Discovery's mission STS-114 last year indicated NOAX is most effective when applied while the temperature of an RCC panel is falling between 120 degrees and 30 degrees Fahrenheit (48 degrees to minus one degree Celsius), so NASA controllers directed Fossum and Sellers to apply NOAX to the pre-damaged RCC panels based on the temperatures of the panels.

Over the course of almost two and a half hours, the astronauts completed three gouge repairs and two crack repairs with NOAX, and provided controllers with a running dialogue describing the repair activity and how the NOAX responded.

Fossum imaged four of the samples with the infrared camera, which he used to gather video of an area of Discovery's port wing while riding Canadarm2 back to the airlock.

Near the end of the spacewalk, controllers added an extra task: Because the spacewalkers were on schedule and had plenty of supplies, they directed Sellers to carry a pistol grip tool to the Integrated Cargo Carrier in Discovery's payload bay and remove the fixed grapple bar he had used during delivery of the pump module during the second spacewalk.

He then carried it to the S1 Truss where Fossum helped him install it on an ammonia tank inside that truss so that the tank can be moved on a later shuttle assembly mission.

Repressurization of the Quest airlock began at 2:31 p.m. Eastern Time, meaning the EVA lasted a total of seven hours and 11 minutes. It was the 68th involved in ISS assembly and maintenance.

The cumulative duration of the three spacewalks on this mission was 21 hours and 29 minutes. Sellers' total spacewalking time of 41 hours and 10 minutes on six EVAs ranks him fourth among U.S. spacewalkers and ninth among all astronauts.

So far, the nine-member combined shuttle and ISS crew has moved several tons of cargo from the Leonardo multi-purpose logistics module to the station, and has carried back trash and unneeded equipment for return to Earth aboard the shuttle.

The current schedule calls for Discovery to undock with the station on Saturday and return to Kennedy Space Center in Florida on Monday. Before undocking, the shuttle crew will perform one more inspection of Discovery's exterior to make sure the heat shield has not been damaged by orbiting debris or meteorite impact. Related Links
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