On behalf of the Kennedy Space Center family, thank you for turning to the STS-109 Countdown Online.

STS-109 will be Shuttle Columbia's 27th space flight, and its first flight in over two years since undergoing maintenance and upgrades following STS-93 in 1999. During this 11-day mission, four mission specialists will perform five spacewalks to complete scheduled maintenance tasks on NASA's Hubble Space Telescope.

Hubble is awaiting several system upgrades, including a new Reaction Wheel, a more efficient Solar Array 3 and a new Power Control Unit (PCU). Hubble's current Faint Object Camera will be replaced by the Advanced Camera for Surveys (ACS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) Cryocooler will be added to the cooling system. If time permits, a New Outer Blanket Layer Insulation (NOBL) will also be installed.

The crew will also conduct several tests and experiments, studying the performance and operations of the Global Positioning Satellite during Shuttle missions and monitoring the crew's sleep-awake activity and light exposure patterns to help us better understand and manage the effects of space flight on sleep.

Thank you for making KSC's Shuttle Countdown Online your source for the latest news regarding STS-109. As always, we at KSC hope you share our excitement for the upcoming mission.