23-story rocket blasts off at Vandenberg

A massive 23-story rocket blasted off from Vandenberg Air Force Base on Thursday shortly after 1 p.m. The three-engine Delta IV Heavy rocket, the tallest ever to be launched from the base, was carrying a top-secret spy satellite for the U.S. government capable of snapping pictures detailed enough to distinguish the make and model of an automobile hundreds of miles below, analysts say.

The massive rocket lifted off from the base’s Space Launch Complex 6. At 235 feet tall, the rocket is so large that base officials worried that the thunderous blastoff would shatter windows nearby.

“We got the word out to people, so they don’t think it’s an earthquake,” said Lt. Ann K. Blodzinski, an Air Force spokeswoman, on Wednesday. “Even if you don’t see it, you’re definitely going to feel it. It’s significantly more powerful than our typical launches at Vandenberg.”

The Air Force closed nearby locations, such as Jalama Beach County Park, as a precaution. But townspeople were expected to come out to see the show, said Lompoc Mayor John Linn. The base is the city’s largest employer.

“Everyone will be in their front yards for this one,” he said Wednesday. “Living here, you get used to launches. But this is different. This is the big kahuna.”

The Space Launch Complex 6 is known on base as “Slick Six.” The launch pad, built in 1969, was once intended to accommodate space-shuttle launches, but they remained in Florida. Since then, the launch pad has gone through many renovations. Most recently, Vandenberg spent $100 million on upgrades over three years.

The rocket was built by United Launch Alliance, a joint venture of Lockheed Martin Corp. and the Boeing Co. It is the nation’s largest unmanned rocket.

Three hydrogen-fueled engines -- each roughly the size of a semi-truck -- provide 17 million horsepower.

When the engines roared to life Thursday, more than 350 Pratt & Whitney Rocketdyne engineers and technicians were watching. It took them five years to develop and four years to assemble the engines at the company’s sprawling Canoga Park facility, said Steve Bouley, the company’s vice president of launch vehicle and hypersonic systems.

“It’s a very complex product,” he said.

Because the launch was closer to home, many Rocketdyne employees were planning to attend the liftoff, Bouley said Wednesday.

The rocket made its maiden flight in 2004 and is capable of lifting payloads of up to 24 tons into low Earth orbit. All four of the previous Delta IV Heavy launches took place at Kennedy Space Center in Cape Canaveral, Fla.

Although little was known about what exactly the rocket would be lifting into space -- because it is classified -- analysts said it was probably a high-powered $1-billion spy satellite. Their speculation was based on the customer being identified as the National Reconnaissance Office, the secretive federal umbrella agency that operates spy satellites.

Though Cape Canaveral is the launch site for NASA’s civilian space program, Vandenberg has been the site of military space projects for more than half a century.

The 98,000-acre base situated along the Pacific Ocean has been the primary site for launching spy satellites since the beginning of the Cold War because of its ideal location for putting satellites into a north-to-south orbit.

william.hennigan@latimes.com