STS-125 Astronaut's conduct the third mission spacewalk to continue work on Hubble

This NASA photo shows astronaut John Grunsfeld, STS-125 mission specialist, as he participates in the mission's third session of extravehicular activity (EVA) as work continues to refurbish and upgrade the Hubble Space Telescope, May 16, 2009 During the six-hour, 36-minute spacewalk, Grunsfeld and astronaut Andrew Feustel (out of frame), mission specialist, removed the Corrective Optics Space Telescope Axial Replacement and installed in its place the new Cosmic Origins Spectrograph. They also completed the Advanced Camera for Surveys electronic card replacement work, and completed part 2 of the ACS repair, installing a new electronics box and cable. (UPI Photo/NASA)