May 18, 2009

Fifth and last Hubble spacewalk under way

The fifth and final planned Hubble Space Telescope spacewalk began Monday with U.S. astronauts John Grunsfeld and Drew Feustel replacing Hubble's batteries.

The National Aeronautics and Space Administration astronauts, who began their spacewalk at 8:20 a.m. EDT, will 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, NASA said. The first battery module was installed during a Friday spacewalk.

They were also to replace 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 precise position and motion of stars.

The Monday spacewalk by the space shuttle Atlantis crew members was to last 5 hours and 45 minutes.