Posted: Sat, May 16, 2009, 10:02 AM ET (1402 GMT)
Two astronauts went into overtime on Friday to complete the replacement of a critical set of components on the Hubble Space Telescope. Astronauts Michael Good and Mike Massimino spent 7 hours and 56 minutes outside Atlantis on Friday, 90 minutes longer than originally planned, to replace gyroscopes and batteries on the telescope. The two fell behind schedule when one of three sets of gyros could not be installed; they instead installed a spare unit. Extending the spacewalk allowed them to replace a battery unit on the telescope as originally planned, rather than deferring the work to a later spacewalk. The third EVA of the STS-125 mission will take place Saturday, when John Grunsfeld and Andrew Feustel will remove an old corrective optics unit from Hubble and install a new instrument, the Cosmic Origins Spectrograph, in its place. The two will also work on repairs to the Advanced Camera for Surveys, which suffered a failure in its power supply in 2007.
