(CBS News) LOS ANGELES -- Slowly surmounting a key obstacle, the shuttle Endeavour was rolling through the streets of Los Angeles toward its retirement home at a science museum.
Endeavour's terrestrial journey began before dawn Friday when it departed from the Los Angeles International Airport, rolling on a 160-wheeled carrier past diamond-shaped "Shuttle Xing" signs.
Friday evening it stopped, and crews spent hours transferring the shuttle to a special, lighter towing dolly. Then around midnight, it traveled over a bridge across Interstate 405, one of the trickiest parts of its complicated journey.
The shuttle was pulled across the Manchester Boulevard bridge by a Toyota Tundra pickup, and the car company filmed the event for a commercial after paying for a permit, turning then entire scene into a movie set complete with special lighting, sound and staging.
Crews preparing for the crossing had to take down power lines, leaving about 400 residents of surrounding Inglewood without power for what was expected to be several hours.
After passing the bridge, crews began the lengthy process of returning it to the original carrier, before resuming its journey early Saturday.
Another tricky part comes later Saturday when Endeavour treks through a narrow residential street with apartment buildings on both sides. With its wings expected to intrude into driveways, residents have been told to stay indoors until the shuttle passes.
On Friday, hundreds of camera-toting spectators, some with pajama-clad children in tow, gaped as the 170,000-pound Endeavour inched by with its tail towering over streetlights and its wings spanning the roadway.
Inside the complexities of Endeavour's final journey through L.A.
Over two days, it will trundle 12 miles at a top speed of 2 mph to its final destination — the California Science Center, where it will be the centerpiece of a new exhibit. It's expected to reach the museum sometime Saturday evening.
After an initial bumpy ride and a brief delay, the shuttle pulled off a massive feat of parallel parking by backing into a shopping center parking lot for a layover as crowds cheered on.
Spectators flocked to the parking lot in the Westchester neighborhood to get a glimpse of Endeavour, which was guarded by an entourage of police, private security and construction crews.
Janet Dion, a family therapist from nearby Manhattan Beach, marveled at the shuttle, its exterior weathered by millions of miles in space and two dozen re-entries.
"You can sense the magnitude of where it's been," Dion said, fixated on the heat tiles that protected the shuttle during the return to Earth.
James Nieuwdorp, a technician for a transit agency, saw Endeavour's aerial victory lap around California last month and traveled to see it again before it becomes a museum piece.
He enjoyed how the shuttle brought strangers together. There was "lot of camaraderie -- something that's hard to be seen these days," he said.
Shuffling a five-story-tall shuttle through urban streets was an undertaking that took nearly a year to plan. Because the 78-foot wingspan hangs over sidewalks in some locations, police enforced rolling street and sidewalk closures along the route.
The limited access frustrated some businesses that counted on huge crowds lining the curbs to boost business.
Saturday is typically the busiest day for James Fugate, who co-owns Eso Won Books in South Los Angeles. But with Endeavour expected to pass 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.
Transporting 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.
Before Endeavour could travel through the streets, some 400 trees were chopped down, cable and telephone lines were hoisted, and steel plates were laid down to protect the streets and underground utilities.
Endeavour was mostly traveling on wide boulevards with some boasting as many lanes as a freeway. While there had been advance preparations, there was remaining work to be done during the move, including de-energizing power lines.
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.