During the third and final spacewalk of mission STS-103, astronauts successfully installed a new control unit, replaced a broken data transmitter and switched out an old tape recorder on the Hubble Space Telescope. Images from NASA.

Christmas Eve walk Steve Smith floats into Discovery's payload bay to begin a Christmas Eve spacewalk to service the Hubble Space Telescope.
Getting set up Spacewalker John Grunsfeld rides on the end of the robotic arm while setting up for the work planned during the EVA.
Adding new controls The spacewalkers move into position for installation of an optical control electronics package.
Moving around Hubble's outer surface is covered with a series of handrails that allow the spacewalkers a way of moving from place to place.
Out with old Spacewalker John Grunsfeld removes an old reel-to-reel tape recorder from Hubble.
In with the new The new solid state recorder is moved into position for installation, replacing the old data system.