Here in the lime-green payload bay of the space shuttle Enterprise, Anne McCombs is going boldly where -- well, where only a few men have gone before. Standing in the shadows cast by innumerable struts, bars and other things to bang your head on, she is in one of the technological marvels of mankind, a vast ship capable of hurtling through space at 17,500 miles per hour, a vehicle capable of taking humans into the airless realm beyond the skies, and she is running a vacuum cleaner.

Vrrrroooommm. Dust and grit, grit and dust. Tiny devils that are the enemy of timeless duration. "You wouldn't believe the level of detail on these things," says McCombs, a restoration specialist at the Smithsonian, gesturing at the surrounding belly of the spacecraft. "Don't even talk to me about the paint job."

The Enterprise -- which, despite its Captain-Kirk-and-Mr.-Spock moniker, flew only in the Earth's atmosphere and never in orbit -- is the mammoth star attraction at today's opening of the James S. McDonnell Space Hangar, the 53,000-square-foot wing of the National Air and Space Museum's Steven F. Udvar-Hazy Center near Dulles Airport. Gutted of its engines, stripped of almost everything in the cockpit, its empty payload bay coated with zinc chromate, the husk of the shuttle anchors the exhibit. With its blunt nose and stubby wings, it looms as an oddly graceful example of man, technology and the dreams that fueled exploration beyond the known world in the latter part of the 20th century.

"Really, there's a lot of cool stuff in here," says Roger D. Launius, chairman of space history for the Smithsonian's Air and Space Museum, walking underneath the Enterprise during a tour of the exhibit last week. "Have you seen the spaceship from 'Close Encounters of the Third Kind'? It's over in the corner." Dominating the room -- and it takes a lot of ship to dominate a room with an 80-foot ceiling -- the Enterprise is surrounded by rockets, spacesuits, Mars explorer modules, 1950 space toys, gadgets from the Apollo and Gemini missions, Soviet rockets and, lest we forget, a floating spaceman.

That would be a mannequin in a mock spacesuit, suspended above the Enterprise in what the techies call the MMU -- the manned maneuvering unit. Essentially a jet-powered backpack, the MMU was the Buck Rogers gizmo of space exploration. It allowed astronauts to move outside the vehicle once in orbit and, say, recapture errant satellites. The unit floating above the Enterprise was the one used by astronaut Bruce McCandless on a Feb. 7, 1984, spacewalk from the shuttle Challenger. Free of any tether, he used the compressed nitrogen jets in the backpack to move 100 yards into space.

"So he was going about 17,500 miles per hour in orbit, plus the speed of the MMU," says Valerie Neal, curator of human space flight at the museum, readying the unit to be hoisted in the air by crane. And about what speed was that?

She stops to figure. "Maybe one mile an hour," she says. In the photographs of that mission, McCandless is floating at a cockeyed angle, framed by the blue Earth and the blackness of the great beyond. Man in space, utterly alone. It became one of the most iconic images of space exploration. Two years later, the image gained a more somber resonance when the Challenger exploded. In the subsequent safety reevaluations, the backpacks were shelved, never to be used again.

The new wing of the museum has been readily visible, but not accessible, to visitors to the Udvar-Hazy Center since the facility opened last December. And like the Udvar-Hazy Center -- the world's largest hangar, full of planes, jets and just about anything else that flies -- the new space wing is more for casual viewing than historical analysis. The labels and text in front of the exhibits are rarely more than a few lines long, and lean more toward simple facts. There will be interactive kiosks in the future, but for now, a tour of the space wing is a stroll through some of the history of space that isn't seen at the Air and Space Museum in Washington. Two million people are expected to have visited the Udvar-Hazy Center by its first anniversary. (Air and Space, by contrast, is the world's most popular museum with an average of 9 million visits per year.)

Launius, the Udvar-Hazy curator, spent an afternoon last week walking through the new gray-floored wing, checking the exhibits a final time. In sports jacket, tie and glasses, he looks the part of the historian who put the exhibit together. Though clearly excited showing off some of the lesser-known items, he acknowledges that the new wing is not intended to compete with the "mothership" museum on the Mall. "Some would say this is 'displayed storage,' and 'the big stuff we couldn't display downtown,' and I don't know that I would dispute that at this stage," he says. "You'll walk by and say, 'Wow, this is big and really complex,' and you'll see the shuttle, but there's nothing to explain to you why we've been flying a shuttle into space for 20 years."

Alongside the shuttle are the engineering models of the Pathfinder lander and Sojourner rover that landed on Mars in 1997 -- and will be there for eternity. There's a copy of the gold record, "Sounds of Earth," that was put aboard the Voyager explorer, launched into the solar system and beyond 27 years ago. Somewhere in the icy darkness of space, it's still aboard, carrying 122 images and sounds, with the indelible return address of "United States of America. Planet Earth." There's also the Corona Film Return Capsule, which -- beer-bottle-and-a-lime jokes aside -- is the name of an odd bit of spy technology once used by the CIA and the Air Force. In the 1960s and early '70s, the agencies packed cameras and huge rolls of film into a golden orb, put it aboard a satellite and sent it into orbit over the Soviet Union. When the film spools were full, the orbs were discharged, floating back to Earth over the Pacific Ocean, where they were snagged, in mid-air, by military planes. The advent of digital photo transmission relegated the Coronas to the heap of outdated gizmos in 1972.

And, in the front left corner of the museum, in a glass case, is the disk-shaped spaceship that hovered above Devil's Tower in Steven Spielberg's "Close Encounters," the movie that thrilled audiences 27 years ago. It is four feet wide. The Enterprise could eat it as a snack. "The whole thing in the movie was just this model," says Launius, grinning. "It was just a toy."

Look closer, and closer still, and there is, perched on the edge of the spaceship, a diminutive model of R2-D2, the robot in "Star Wars." And at the front, on the first level of the ship, is a tiny graveyard, complete with tiny headstones. At the back there are a couple of World War II-era planes parked on a tarmac. On top of the ship are the red/green lights from road-track intersections on model train sets.

"You couldn't see any of that in the film, but the model makers just had a blast with it," says Launius. He turns to face the rest of the museum, the project he has spent years helping to assemble. He considers the total effect, from real spacecraft to make-believe models to massive rockets and bulky engines, the whole room speaking of energy and restless curiosity.

"Five hundred years from now, whoever's around ought to be able to see these things and learn something about us. It says something about who we are."

Among the artifacts at the Udvar-Hazy Center's James S. McDonnell Space Hangar: Pressurized suits and the shuttle Enterprise. Every necessity of life: A cosmetics kit for female astronauts is among hundreds of artifacts in the McDonnell Space Hangar.