Live At KSC: Shuttle Fuel Cell Loading Under Way

LIVE IMAGES: The images above are from live video feeds in the Launch Complex 39 area at Kennedy Space Center, where Endeavour is being readied for launch Saturday on an International Space Station assembly mission. They will automatically refresh to the most up-to-the-minute image every 30 seconds.

NASA is loading supercold liquid hydrogen and liquid oxygen into shuttle Endeavour's fuel cell system as countdown clocks tick toward the planned launch Saturday of an International Space Station assembly mission.

Endeavour and seven astronauts are scheduled to blast off from launch pad 39A at Kennedy Space Center at 7:17 a.m. Saturday. The weather forecast calls for a 90-percent chance that conditions will be acceptable for launch, and NASA is not working any technical showstoppers.

NASA picked up a standard three-day launch countdown at 9 a.m. and now is servicing the shuttle's three fuel cells. Supercold liquid hydrogen and liquid oxygen will be combined in the fuel cells to generate the electrical power required to operate all spaceship systems during Endeavour's planned 16-day mission.

Engineers began loading the cryogenic chemical reactants into spherical tanks beneath Endeavour's payload bay liner at 6:30 a.m. The operation is expected to take about six hours.

NASA has two briefings on the schedule today.

The Japan Aerospace Exploration Agencywill hold a briefing at 11 a.m., and NASA's L-2 prelaunch news conference is scheduled to take place no earlier than noon.

You can watch both live here in The Flame Trench. Simply click the NASA TV box on the righthand side of this page to launch our NASA TV viewer and be sure to refresh this page for periodic updates.

The Endeavour crew is led by veteran astronaut Mark "Roman" Polansky and includes pilot Douglas Hurley and five mission specialists: Christopher Cassidy, Thomas Marshburn, Timothy Kopra, David Wolf and the Canadian Space Agency's Julie Payette.

Polansky and Hurley are flying the Shuttle Training Aircraft, practicing landings, at this hour. The roar of the Gulfstream II can be heard across the Launch Complex 39 area.

The astronauts aim to deliver the third and final segment of the Japanese Kibo science research facility to the station. The segment is a pallet-like platform for microgravity science experiments that will be attached to the outside of the Kibo laboratory module.

An on-time launch would lead to a 12:18 a.m. June 29 landing here at KSC.