STS-125 MS1 Good and MS4 Massimino during EVA4

STS-125 Mission Specialist 1 (MS1) Michael Good, positioned on a foot restraint on the end of Space Shuttle Atlantis' Remote Manipulator System (RMS), and MS4 Mike Massimino (lower right, partially out of the frame) participate in the mission's fourth session of extravehicular activity (EVA4) as work continues to refurbish and upgrade the Hubble Space Telescope. During the eight-hour, two-minute spacewalk, Good and Massimino continued repairs and improvements to the Space Telescope Imaging Spectrograph (STIS) that has helped extend Hubble's life.

Credits: NASA