July 8, 2013
Astronauts Aboard ISS Prepare For Spacewalk On Tuesday
Lee Rannals for redOrbit.com - Your Universe Online
Astronauts aboard the International Space Station (ISS) will embark into the abyss on Tuesday for the first of two planned July spacewalks.
Cassidy will be moving to the top of the Z1 truss to remove and replace a Space-to-Ground Transmitter Receiver Controller, which is one of two units that allows for independent strings of Ku-band communication for video and data.
Parmitano will be making his way to the Express Logistics Carrier-2 on the starboard truss segment and retrieve two experiments that were part of the Materials International Space Station Experiment-8 (MISSE-8). These experiments, including the Optical Reflector Materials Experiment III (ORMatE-III) and the Payload Experiment Container, assessed the impacts of the space environment on materials and processor elements. They are scheduled to return to Earth aboard the upcoming SpaceX Dragon cargo mission later this year.
The ESA astronaut will also be photographing the Alpha Magnetic Spectrometer-02 (AMS-02) to provide the research team with a visual assessment of the condition of this particular physics detector.
Cassidy and Parmitano will be joining together to remove two Radiator Grapple Bars (RGBs) and install one on the port side truss and the other on the starboard side so they will be more strategically located. These instruments are intended to help in the removal and replacement of failed thermal radiators. Parmitano will ride at the end of the station's Canadarm2 robotic arm to transport the RGBs to the worksites where Cassidy will bolt them down.
As Parmitano gets a lift from the Canadarm2, he will remove a failed camera assembly, the Mobile Base Camera Light Pan-Tilt Assembly, which failed back in May 2012 just before arrival of the Japanese H-II Transfer Vehicle. This camera assembly was one of the prime viewing systems for monitoring visiting vehicles. It will be returning back to Earth for refurbishment and return to the station later as a spare.
Cassidy will be routing power cables to support the addition of the new Russian Multipurpose Laboratory Module scheduled to arrive at the station later this year. He will route cables from the Unity node to the interface between the Pressurized Mating Adapter-1 and the Zarya module. The NASA astronaut will also begin the installation of the two Z1 truss Y-bypass jumpers to provide power redundancy and stability for critical station components.
Cassidy had to perform an emergency spacewalk back in May to repair an ammonia coolant leak on the space station. He and Tom Marshburn spent over two and one-half hours removing the 260-pound pump controller from the P6 truss and replacing it with a spare one.