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 credit: 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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Contributing Writer

James Dean is a former space reporter at Florida Today, covering Florida's Space Coast through 2019. His writing for Space.com, from 2008 to 2011, mainly concerned NASA shuttle launches, but more recently at Florida Today he has covered SpaceX, NASA's Delta IV rocket, and the Israeli moon lander Beresheet.