Astronauts Begin Fifth and Final Spacewalk To Repair Hubble

Astronauts John Grunsfield and Andrew Feustel began the fifth and final spacewalk of their Hubble Space Telescope repair mission this morning at 8:20AM.

During their spacewalk the two will install the second battery group replacement in an equipment bay above the Wide Field Camera 2 and next to the compartment where the first battery set was installed on the second spacewalk. Each of the battery module weighs 460 pounds and contains three batteries. The batteries provide electrical power to support Hubble's operations during the night when there's no sun to power the solar arrays.

After replacing the second battery set, the two will begin removing and replacing one of the three Fine Guidance Sensors, FGS-2, which are used to provide pointing information for the spacecraft.

Lastly, the two spacewalkers will turn their attention to the New Outer Blanket Layer (NOBL) on the outside of the telescope's Bay 5. The NOBL was scheduled to be replaced during the last spacewalk that took place yesterday but the crew were unable to accomplish it during the spacewalk.

In addition to the NOBL on the outside of Bay 5, Mission Control may also ask them to install a full or partial set of NOBLs on Bay 8 -  time permitting.

The spacewalk today is scheduled to last nearly 6 hours.