STS109-E-5660 (6 March 2002) --- Astronauts John M. Grunsfeld (top) and Richard M. Linnehan participate in a 6 hour, 48 minute space walk designed to install a new Power Control Unit (PCU) on the Hubble Space Telescope (HST). The two went on to replace the original unit launched with the telescope in April 1990. Grunsfeld is on the end of Columbia's Remote Manipulator System (RMS) robotic arm, controlled from inside the crew cabin by astronaut Nancy J. Currie. The image was recorded with a digital still camera.