Fueling Problem Delays Launch of Huge Rocket Carrying Secret U.S. Satellite

Essential U.S. Spy Satellite Launching Friday
File photo: United Launch Alliance’s Delta 4-Heavy rocket blasts off carrying a new classified payload for the NRO in a successful Jan. 17, 2009 launch from Cape Canaveral Air Force Station in Florida.
(Image: © Roger Guillemette for SPACE.com)

CAPE CANAVERAL, Fla. ? Abnormaltemperature readings during fueling prompted the scrub of Friday night'splanned launch of a secret satellite atop a Delta 4 Heavy rocket.

United Launch Alliance plans to announce thetiming of a new launch attempt by this afternoon after further analysis of theproblem.

The giant rocket was preparing to blast offfrom Cape Canaveral Air Force Station at 6:06 p.m. Friday with a classifiedNational Reconnaissance Office spacecraft.

Supercold liquid hydrogen and liquid oxygenpropellants began pumping into the rocket's three side-by-side first-stageboosters at 1 p.m.

But launch teams cut the process short and begandraining the tanks a little more than an hour later after detectingirregular temperatures in the left and right boosters.

The target launch timewas briefly reset to 8:30 p.m. as troubleshooting continued, but a scrub wasofficially called at 3:45 p.m.

"The Delta 4 Heavy and payload are safeand secure," ULA said in a statement.

The scrub came two weeks after a fuelingproblem scrubbedshuttle Discovery's launch from Kennedy Space Center, which is now plannedno earlier than Dec. 3.

The rocket's countdown already had beendelayed a day while crews replaced a faulty ordnance line at Launch Complex 37.

After the scrub, a 330-foot mobile servicetower was rolled back into place around the 23-story rocket to give techniciansaccess to sensors and instruments on the boosters.

If a launch attempt is possible Sunday, Nov.21, the weather forecast remains excellent with a 90 percent chance offavorable conditions.

The launch would be the fourth by a Delta 4Heavy, the nation's mostpowerful liquid-fueled rocket.

Designed to haul very heavy payloads, therocket flew a demonstration flight in 2004 and successful operational missionsin 2007 and 2009.

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