S103-E-5366 (24 December 1999) --- Astronauts John M. Grunsfeld (left), mission specialist, and Steven L. Smith, payload commander, are pictured prior to donning their extravehicular mobility unit (EMU) space suits onboard Discovery's mid deck. Hours later, the two completed the third and final space walk scheduled for NASA's third servicing mission to the Hubble Space Telescope (HST).