Fourth Spacewalk in Progress

STS-125 Mission Specialists Michael Good (left) and Mike Massimino participate in the mission's fourth session of extravehicular activity as work continues to refurbish and upgrade the Hubble Space Telescope.

During the eight-hour, two-minute spacewalk, Massimino and Good continued repairs and improvements to the Space Telescope Imaging Spectrograph that will extend the Hubble's life into the next decade.

Photo credit: NASA

May 17, 2009