A large section of Discovery's nose, called the forward reaction control system, which helped steer the shuttle while in orbit, was removed in March. The spacecraft will be cleaned and detoxified before being put on display in museums.
Once space shuttle Atlantis touches down on Earth later this week, workers will start the process of transforming the spaceship into a museum piece.
To see how that mothballing process will unfold, I recently went on a rare tour of Discovery, one of NASA's other shuttles.
Discovery was set up with its landing gear down in a secure hangar at Kennedy Space Center in Florida, where technicians normally do work on the shuttles after each flight.
To make sure no foreign objects ended up in the historic spaceship, my rings had to be taped to my fingers, and my eyeglasses had to be tethered to my head. My press pass had to be taken off and hung in a special rack.
Inside the hangar, Discovery was surrounded by so many platforms and pipes and equipment that at first I couldn't even see it. I climbed some stairs, turned a corner, and came face to face with its nose cone. I almost didn't recognize it because big pieces of it were missing.
"It is different for a lot of folks here to see it looking like that," said Stephanie Stilson, who is in charge of ground operations for Discovery, a job she has had for over a decade.
She explained that as they get this ship ready for the Smithsonian's National Air and Space Museum, they need to take out some parts that normally don't get removed, like from inside the nose cone.
But a lot of the processing feels routine, and Stilson likes to pretend that it is.
"The work that we're doing is very similar to the work we would do if it was going to fly again," she said. "So for someone like me, who doesn't really want to address the fact that these vehicles aren't flying again, it's kind of nice to just let yourself get absorbed into the work."
Preparing For The Museum
An engine is removed from space shuttle Endeavour after its final mission. Lookalike engines will replace the real ones when the shuttles go on display.
An engine is removed from space shuttle Endeavour after its final mission. Lookalike engines will replace the real ones when the shuttles go on display. Chris Chamberland/NASA
Her team has been going over the ship and getting rid of any toxic materials that could pose a danger once Discovery is on display.
"The minute the vehicle lands on the runway, it's a hazardous vehicle that has to be handled very carefully," Stilson explained. "So there are things that can offgas, that could make you feel sick and so forth. There are things that could leak and drip on your skin and cause damage. So that's what we're taking care of right now."
I walked on a raised platform along the side of the ship, right past the big black letters that say "United States," went down a staircase and found myself under Discovery's belly. I looked up and saw a vast expanse of heat shield tiles. The square tiles are white with some gray in them — it looked to me like a marble ceiling.
Usually any damaged tiles will be repaired to protect crews in future missions. But this time, with no more flights planned, the tiles will be left as they are.
Another staircase took me up to the rear of the ship, where I saw the guts of the spacecraft through three giant circular openings — empty spots where the massive engines used to sit.
Technician Jack Colella told me that the engines are taken out after every flight for inspection. This time, though, they aren't going back in. Instead, they'll be replaced with fake lookalikes. "From the outside, looking at it at the museum, it'll look like the engines are fully installed," he said.
'We Knew This Was Coming'
Colella, who has been with the shuttle program for 23 years, said working on Discovery feels different now that it's Earthbound. "But we knew this was coming," he said. "We've just got to get her ready and let her rest in the Smithsonian once we get her there."
To go inside Discovery, first I walked through an enclosed white passageway set up next to the ship. The walls of this entry room are covered with black marker — the signatures of people who have visited the shuttles in this hangar over the years.
Then I climbed awkwardly onto a platform and scooted, feet first, into the body of Discovery. The interior was surprisingly small. Up a narrow ladder was the flight deck — a cramped gray cockpit completely covered with buttons and switches. The blue seats for the commander and pilot looked thin and hard.
Below it was the mid-deck, a windowless space about the size of an office cubicle. During a mission, the astronauts sitting here would have even less room because this space would be crammed with lockers full of food and clothes, explained technician Charles Bell, who has worked with the shuttles since 1988.
Shuttle Through The Decades
Discovery still feels ready to fly, Bell said. But as the ship gets closer and closer to being ready for the museum, he said, he expected things to get more difficult.
"Especially once it gets on display, it'll be lifeless," Bell said. "Right now it's still got some life in it. It'll be hard seeing them dead and gone, so to speak."
Like the shuttles, Bell said he's about to retire. He's one of thousands of people leaving the space program.
These workers have known the shuttles well, inside and out. But in the future, if they want to visit, they'll have to join the throngs of tourists expected to surround the spaceships once they reach their new homes: the Smithsonian, the Kennedy Space Center Visitor Complex, and the California Science Center in Los Angeles.