Live At KSC: Shuttle Launch Countdown Under Way

A three-day countdown just got underway at Kennedy Space Center as NASA continues to gear up for the planned launch Saturday of shuttle Endeavour and seven astronauts on an International Space Station assembly mission.

A team of about 150 to 200 NASA and contractors engineers were called to their stations in Firing Room 4 of the Launch Control Center here at 8:30 a.m. and then countdown clocks began ticking back from the T-Minus 43 hour mark at 9 a.m.

Endeavour and its crew are scheduled to launch at 7:17 a.m. Saturday on a mission to deliver the third and final segment of the Japanese Kibo science research facility to the station.

The weather forecast for launch is near-perfect. Meteorologists say there is a 90 percent chance that conditions will be acceptable for an on-time liftoff. That's up from 80 percent in the forecast yesterday. The only concern is a chance of cumulus cloud development in the launch area.

Click here for the Official Launch Forecast from the Air Force 45th Space Wing Weather Squadron.

Engineers today aim to checkout back-up flight systems and review flight software stored in shuttle mass memory units and display systems.

Back-up flight software will be loaded into the shuttle's general purpose computers and spaceship navigation systems will be activated around 7 p.m. tonight.

Preparations for fuel cell service will be complete around 8 p.m.

Fuel-cell servicing is on tap Thursday and engineers will begin loading the shuttle's external tank at 9:52 p.m. Friday.

A countdown status briefing is scheduled for 10 a.m. You can watch it live here in The Flame Trench. Simply click the NASA TV box at the righthand side of the page to launch our NASA TV viewer and be sure to refresh this page for periodic updates.

NASA will have three days to get the shuttle mission under way before the agency would stand down for the planned June 17 launch of an Atlas V rocket and NASA's Lunar Reconnaissance Orbiter.

ABOUT THE IMAGE: Click to enlarge and save the NASA photo of the payload for the STS-127 mission inside shuttle Endeavour's cargo bay. The payload includes, at bottom, the Integrated Cargo Carrier-Vertical Light Deploy (with the Space-to-Ground Antenna showing), the Experiment Logistics Module-Exposed Section (middle) and the Japanese Experiment Module's Exposed Facility (at top). The payload bay doors were closed for flight over the past weekend. Photo credit: NASA/Jack Pfaller.