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

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

United Launch Alliance plans to announce the timing of a new launch attempt by this afternoon after further analysis of the problem.

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

Supercold liquid hydrogen and liquid oxygen propellants began pumping into the rocket's three side-by-side first-stage boosters at 1 p.m.

But launch teams cut the process short and began draining the tanks a little more than an hour later after detecting irregular temperatures in the left and right boosters.

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

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

The scrub came two weeks after a fueling problem scrubbed shuttle Discovery's launch from Kennedy Space Center, which is now planned no earlier than Dec. 3.

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

After the scrub, a 330-foot mobile service tower was rolled back into place around the 23-story rocket to give technicians access 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 of favorable conditions.

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

Designed to haul very heavy payloads, the rocket flew a demonstration flight in 2004 and successful operational missions in 2007 and 2009.

• Stunning Night Lights: Photos of New Spy Satellite's Launch
• Gallery - The Air Force's Secret X-37B Space Plane
• Most Destructive Space Weapons Concepts

Published under license from FLORIDA TODAY. Copyright ? 2010 FLORIDA TODAY. No portion of this material may be reproduced in any way without the written consent of FLORIDA TODAY.