LOS ANGELES » At its prime, the space shuttle Endeavour cruised around the Earth at 17,500 mph, faster than a speeding bullet.

In retirement, it’s crawling along at a sluggish 2 mph, a pace that rush-hour commuters can sympathize with.

Endeavour’s 12-mile road trip kicked off shortly before midnight Thursday as it moved from its Los Angeles International Airport hangar en route to the California Science Center, its ultimate destination, said Benjamin Scheier of the center.

The shuttle rolled through the streets of neighboring Westchester for about three miles and then, in a massive feat of parallel parking, the 170,000-pound spacecraft was backed into a parking lot near a strip mall.

At the airport, Endeavour was briefly delayed after a minor problem developed with its trailer, Los Angeles police Sgt. Rudy Lopez said.

It reached the streets shortly after 2 a.m. today. The immense black-and-white spacecraft, its sides weathered by millions of miles in space and two dozen re-entries, rolled slowly on a 160-wheeled carrier.

Hundreds of people waiting in the predawn darkness snapped photos and gaped as it inched by with its tail towering over streetlights and its wings spanning the roadway. Some had pajama-clad children in tow.

The shuttle made stop-and-go progress, with some halts to check its balance and to prune trees in its path as it rolled past strip malls, storefronts, apartment buildings and front lawns.

It arrived at the parking lot at around 5:30 a.m. — some two hours late.

"It’s still a work in progress," Scheier said of the journey.

Ushering a shuttle through an urban core is a logistical challenge that took almost a year to plan. Guarded by a security detail reminiscent of a presidential visit, police enforced rolling street and sidewalk closures as early as Thursday night in some locations and discouraged spectators from swarming side streets.

The behemoth transport has caused headaches for shopkeepers along the route who counted on cheering crowds jamming the curbs to boost business.

In the days leading up to Endeavour’s move, the owners of Randy’s Donuts sold shuttle-shaped pastries emblazoned with the NASA logo and even hung a shuttle replica inside the giant doughnut hole sign visible from the busy Interstate 405.

Co-owner Larry Weintraub planned to watch the shuttle creep by the roadside sign, which has been featured in several movies. But the store, which serves up sweets 24-7, will be closed tonight.

"I’m still excited, but I’m disappointed that people aren’t going to be able to stand in the streets and shout ‘Yay,’" he said.

Saturday is typically the busiest day for James Fugate, who co-owns Eso Won Books in South Los Angeles. But with Endeavour expected to shuffle through, Fugate braced for a ho-hum day in sales.

"We don’t close because we’re slow. That’s when you pull out a book to read," he said.

The baby of the shuttle fleet, Endeavour replaced Challenger, which exploded during liftoff in 1986, killing seven astronauts. It thundered off the launch pad 25 times, orbited Earth nearly 4,700 times and racked up 123 million miles.

Last month, it wowed throngs with a dizzying aerial loop, soaring over the state Capitol, Golden Gate Bridge, Hollywood Sign and other California landmarks while strapped to the back of a modified 747 before finally landing at LAX.

The last leg of Endeavour’s retirement journey skips the tourist attractions and instead, winds through blue-collar communities in southern Los Angeles County. While viewing will be severely curtailed due to sidewalk shutdowns, crowds are still expected.

Moving the Endeavour required a specialized carrier typically used to haul oil rigs, bridges and heavy equipment. The wheels can spin in any direction, allowing the shuttle to zigzag past obstacles. An operator walks alongside, controlling the movements via joystick. Several spotters along the wings are on the lookout for hazards.

To make room for the five-story-tall shuttle and its 78-foot wingspan, some 400 trees were chopped down, cable and telephone lines were raised, and steel plates were laid down to protect the streets and underground utilities.

Endeavour will mostly travel on wide boulevards with some boasting as many lanes as a freeway. While there have been advance preparations, there is remaining work to be done during the move, including de-energizing power lines. Southern California Edison warned of outages in the suburb of Inglewood.

One of the trickiest parts involves trundling through a narrow residential street with apartment buildings on both sides. With Endeavour’s wings expected to intrude into driveways, residents have been told to stay indoors until the shuttle passes.

The route was selected after ruling out other options. Dismantling the shuttle would have ruined the delicate heat tiles. Helicoptering it to its destination was not feasible. Neither was crossing on freeways since the shuttle is too big to fit through the underpasses. The cost of transporting it cross-town was estimated at over $10 million.

As complex as the latest endeavor is, Southern California is no stranger to moving heavy things.

In 1946, Howard Hughes’ "Spruce Goose" aircraft was built in sections and hauled from Culver City to Long Beach, 30 miles away. In 1984, an old United Airlines DC-8, with its wings and tail disassembled, was towed from Long Beach to the science center.

Earlier this year, a two-story-tall chunk of granite was hauled 105 miles from a rock quarry to the Los Angeles County Museum of Art.