Astronauts complete needed tasks during spacewalk

CAPE CANAVERAL, Fla. -- An American and an Italian astronaut took a stroll in space outside the International Space Station on Tuesday to perform much needed repairs and to retrieve a few experiments.

American Chris Cassidy and Italian astronaut Luca Parmitano spent just over six hours working in space, marking the second spacewalk of the year by an American.

Today's six hour, seven minute spacewalk officially began at 8:02 am EDT, as the pair switched their spacesuits to internal power. They then opened the station's Quest airlock hatch and floated outside.

This marked the first time an Italian astronaut walked in space, and was the first spacewalk by a European since February 2008.

As the orbital laboratory soared 260 miles above Saudi Arabia in the darkness of night, the pair adjusted to their new surroundings to prepare for their first tasks.

Cassidy, wearing red stripes on his spacesuit, went right to work ten minutes later to replace a Ku-Band video and data transmitter controller. One of two used to send and receive information from the ground failed in December.

The new controller will give the space station "redundant capability for the station's Ku-Band" transmissions, stated NASA's Rob Navis during the spacewalk.

Using a space styled wrench known as a pistol grip tool, Cassidy had trouble with a stubborn bolt, and tried adjusting the proper torque setting to release the bolts which held the controller in place on the station's Z1 truss.

Meanwhile, Parmitano translated over to the station's right side truss to retrieve a couple of NASA experiments known as MISSE 8 which tested the effects of direct sunlight, radiation and the other harmful elements in the vacuum of space.

NASA will use the results from Materials on International Space Station Experiment 8 as they look for the best materials to create new spacecraft as they steer toward deep space flights by astronauts during the 2020's.

As the Italian astronaut returned the two experiments back to the Quest airlock for their return to earth later this year, Cassidy commented to Parmitano, "Outstanding! Nice job".

Cassidy later strung a few new power cables along a section of the station in a task which will be completed during a upcoming spacewalk to support of a new Russian laboratory module.

Russia plans to launch it's Nauak module in December, and will also serve as an airlock and docking port beginning in 2014.

Parmitano received an out of this world view of both the space station and earth as he rode high above at the end of the Canadian-built 57-foot robotic arm as he and Cassidy removed and replaced two radiator grapple bars.

Inside the American Destiny module, Karen Nyberg controlled the robotic arm and swung Parmitano over to the region of the station's truss so that Cassidy could bolt the grapple bars down on either side.

NASA's Josh Byerly explained to this aerospace reporter today that the new grapple bars will help in case one of the station's extended thermal radiators fail and needs to be replaced.

The thermal radiators are located across the core truss and help transfer heat from the station's electronics out into space.

Tuesday's spacewalk marked the 170th to support maintenance and construction of the space station since 1998.


(Charles Atkeison reports on aerospace, science and technology. Follow his updates via Twitter @SpaceFlight360.)