Image above: STS-125 Mission Specialist John Grunsfeld is attached to the shuttle's robotic arm during the fifth spacewalk to repair the Hubble Space Telescope. Photo Credit: NASA

Astronauts complete fifth and final spacewalk

STS-125 mission specialists John Grunsfeld and Drew Feustel completed the fifth and final spacewalk on the Hubble Space Telescope Monday at 3:22 p.m. EDT.

Outside the airlock hatch, Grunsfeld, KC5ZTF said,
"This is a really tremendous adventure that we’ve been on, a very challenging mission. Hubble isn’t just a satellite - it’s about humanity’s quest for knowledge."

He also thanked several people who contributed to Hubble and the servicing mission, then went on to say,

"A tour de force of tools and human ingenuity. On this mission in particular, the only way of finding the limits of the possible is by going beyond them into the impossible.

On this mission, we tried some things that some people said were impossible….We’ve achieved that, and we wish Hubble the very best. It’s really a sign of the great country that we live in that we’re able to do things like this on a marvelous spaceship, like space shuttle Atlantis. I’m convinced that if we can solve problems, like repairing Hubble, getting into space, doing the servicing we do, travelling 17,500 mph around the Earth, we can achieve other great things, like solving the energy problems and climate problems- all of the things that are in the middle of NASA’s prime and core values. As Drew and I go into the airlock, I want to wish Hubble its own set of adventures and with the new instruments that we’ve installed that it may unlock further mysteries of the universe."

Grunsfeld and Feustel finished the mission’s battery replacement work. They worked in the telescope’s Bay 3 to replace the second of two battery modules. Each module weighs 460 pounds and contains three batteries, providing electrical power to support Hubble operations during the night portion of its orbit. The first battery module was installed during the second spacewalk.

They also replaced one of the telescope’s fine guidance sensors. The sensors are used to provide pointing information and also serve as a scientific instrument for determining relative position and motion of stars.

After those two tasks were accomplished, Feustel and Grunsfeld turned their attention to the New Outer Blanket Layer (NOBL) on the outside of the telescope’s Bay 5, Bay 8 and Bay 7, which normally face in the direction of Hubble’s orbital travel. These blankets were expected to deteriorate more in the space environment. The NOBL on Bay 8 was to be installed during the fourth spacewalk, but the crew was unable to accomplish it due to work on a stripped bolt.

Monday’s spacewalk lasted 7 hours and 2 minutes.