(11/13/1999) -- Space Shuttle Discovery, atop the mobile launcher platform and crawler transporter, nears the top of Launch Pad 39B after a 4.2-mile crawl from the Vehicle Assembly Building. At left are the Rotating Service Structure and the Fixed Service Structure, which will enable final preparations of the orbiter, external tank and solid rocket boosters for the STS-103 launch targeted for Dec. 6, 1999, at 2:37 a.m. EST. The mission is a 'call-up' due to the need to replace and repair portions of the Hubble Space Telescope. Although Hubble is operating normally and conducting its scientific observations, only three of its six gyroscopes are working properly. Four EVA's are planned to make the necessary repairs and replacements on the telescope. The STS-103 crew members are Commander Curtis L. Brown Jr., Pilot Scott J. Kelly, Steven L. Smith, C. Michael Foale (Ph.D.), John M. Grunsfeld (Ph.D.), and Claude Nicollier of Switzerland and Jean-François Clervoy of France, both with the European Space Agency