Second Atlas V Countdown Under Way At Cape

The countdown to the second attempt to launch an Atlas V rocket on a critical military satellite deployment mission is under way at Cape Canaveral Air Force Station today, and it appears the weather is going to be good to go.

The 189-foot-tall United Launch Alliance rocket and its payload -- a new-generation missile-warning satellite -- are scheduled to blast off from Launch Complex 41 at 2:10 p.m. A 40-minute launch window will extend through 2:50 p.m.

The weather forecast calls for a 90 percent probability that conditions will be acceptable for flight. Thick electrically charged clouds that could cause the rocket to trigger destructive bolts of lightning in flight prompted the scrub of an initial launch attempt on Friday.

Launch managers squeezed out every available minute in yesterday's launch window, picking up the countdown at T-Minus 4 minutes as the close of the window approached -- even though the Eastern Range was "no-go" for cumulus clouds. Clocks ticked down to 60 seconds before the Mission Flight Control Officers yelled "HOLD, HOLD, HOLD." Launch controllers recycled the clock to T-Minus 4 minutes and prepared to pick up the countdown again but time ran out.

The $1.2 billion Space-Based Infrared System (SBIRS) spacecraft is a follow-on of the Defense Support Program satellites that have provided early warning of Intercontinental Ballistic Missile (ICBM) launch since the 1970s.

Over the next several hours the launch team will be performing routine pre-launch checkout of rocket and spacecraft systems. Propellant-loading operations are scheduled to begin just after 12:15 p.m.