Two of the space shuttle Discovery's astronauts will head back outside of the international space station late today as they prepare the outpost for the February arrival of the final U.S. module, Tranquility.
Mission specialists Danny Olivas and Christer Fugelsang (European Space Agency) are scheduled to switch their suits on internal power and head out of the station's Quest airlock at 4:49 pm EDT. The spacewalk is planned to last six and one-half hours.
A few of the prime tasks planned for this evening will be the replacement of a rate gyro assembly which failed several months ago. The orbital duo will disconnect cables and each remove two attachment bolts apiece to remove the old gyro. They then will install a new gyro and then store the old one for it's return back to earth.
Next, Olivas will separate from Fugelsang and transition over to the PMA-3 and set up a few heater cables, with one of them connected to the Unity module and the others tied down on one of the module's handrails. The cables will be used to connect the module with the upcoming arrival of the Tranquility module.
Tranquility is a pressurized module which will have windows providing a 360-degree view of the space station, and provide living quarters for off-duty residents. Endeavour will bring Tranquility to the station in February.
As Olivas works with the heater cables, Fugelsang will work to replace an nonoperational power control module located at the center of the space station. The removal and installation will be a one bolt operation.
This will be the 133rd spacewalk devoted to the construction of the space station.