NASA added the mission to the shuttle manifest in March to make sure a faltering positioning system wouldnt shut down Hubbles bustling observation program. The telescope is operating without backups to a crucial system of six gyroscopes used to aim the observatory at stars, planets and other celestial targets.

All six gyroscopes will be replaced during the October shuttle flight, as well as a guidance sensor, the spacecrafts main computer, a data recorder and other equipment.

Pallets containing the equipment, as well as the platform to which the telescope will be attached during spacewalks to install the new gear, will be arriving at the launch site aboard a cargo jet transporter on Thursday, said Kennedy Space Centers payload director Stephen Francois.

Trucks and trailers will then transport the equipment to a payload processing building for final launch preparations. NASA is planning to launch the nine-day repair mission on Oct. 14 aboard shuttle Discovery.