The entrance door to the Mission 2 Operations Control Room (Mocr-2), located on the third floor of NASA's Johnson Space Center in Houston, is nothing special.
Only the slightly worn panel screwed on the gray paint issued by the government gives you a clue to its historical significance.
The sign lists 42 missions covering more than a quarter century. They go from Gemini 4 in 1965 – during the first American exit – to the Apollo missions on the Moon, to the first flights of the space shuttle.
Some of the most dramatic moments in modern human history, including the first landing of the Moon, the rescue of Apollo 13 and the Challenger disaster, were passed over this hall.
You might also like:
"The place was nice to live in, a bit like putting on a well-fitting glove," says Gerry Griffin, Director of Apollo Mission Flights. "When I come back to it now, it looks a bit more like a cathedral – an almost respectful place."
Go through the door and it is clear that this cathedral has seen better days. Although Mocr-2 has been preserved as a national historic landmark, its condition has deteriorated since its last use in the early 1990s. To such an extent that it has recently been designated as "threatened." The iconic control consoles were damaged and the room became dilapidated and worn out.
Now, in anticipation of the 50th anniversary of the first landing of the moon in July, NASA is working to restore control of the Apollo mission. At this stage of the conservation project, however, Mocr-2 seems worse than ever.
The screens are blank, the ceiling tiles are missing, the walls are exposed and the carpet is stained and torn. Post-it numbered stickers cover surfaces where objects have been removed. The chairs and some of the iconic consoles were washed away to be restored, while others are covered with a plastic tarpaulin.
Nevertheless, there is always something very special about this piece. "Even now, when everything is stripped and there is nothing, not even a flag, you know it's different," says Sandra Tetley, NASA's historical preservation officer. "You can say that the story was made here, you feel it."
The lights will flash, the clocks will work, the projections on the screens, it will be things placed on the consoles – manuals, coffee and cigarette butts in the ashtrays – Sandra Tetley
Tetley oversees the restoration project which, six months from the end, still has a very long list of tasks to do. Restoration, rather than renovation – "I hate the word," says Tetley – is the name of the game.
"The idea is that when you enter the viewing room at the back, you go back in time and you get the impression that the flight controllers have just moved away from their consoles," he says. she. "It will be blinking lights, clocks that will work, projections on the screens, things will be placed on the consoles – manuals, coffee and cigarette butts in the ashtrays."
In the high-stakes, high stress environments of mission control in the 1960s, coffee and cigarettes played a major role. "Everyone was smoking, everyone was drinking coffee," Griffin said. "You could see the smoke in the room – and the smell must be horrible, with smoke and a bunch of dead bodies, but we did not notice, because we were there all day."
Preserving some of this atmosphere is one of the goals of the restoration. "The initial ceiling was white, but with the cigarette tar, it has yellowed over the years," says Tetley. "We leave all this dirt so that you can always see that yellowish color."
The walls will also be restored with their original motif. "In the plans, we did not have wallpaper, but then we found an original piece of paper behind a fire extinguisher," she says. "We were able to go back to the manufacturer and they found the roll that made the wallpaper, so we were able to recreate it."
It's a similar story with the carpet, with fragments of the original found under the consoles. Another re-discovery when they removed the consoles was a system of pneumatic tubes. Mission controllers used them to send cartridges containing messages to and from their support teams around the Houston compound.
As part of the restoration and complete overhaul of modern electronics, these screens and the clocks located above them will come back to life.
"They were sending notes back and forth, and the flight controllers said that one of the really interesting things in this room was to hear that noise – it was the shuum, the shuum with these pneumatic tubes on, "says Tetley. "They do not work anymore, but the controllers say that among the things that they inserted into these tubes, there were hot dogs and mice!"
Given the drama that has taken place in this room, it may be appropriate that the Mocr-2 design look like a theater, with a viewing gallery at the back, and then a rack of consoles overlooking screens going from floor to ceiling. The video and data displayed here were back-projected from a hidden, windowless room behind the screen, called "The Bat Cave."
As part of the restoration and complete overhaul of modern electronics, these screens and the clocks above them will come back to life. And another room, to the right of the screens, is also being rebuilt. This was the simulation control room, where a training team could simulate problems that may occur during missions.
"Simulation specialists have left us with errors to see how we manage them," says Griffin. "They gave us an error and we solved the problem, then another, then another, so they finally got us on their knees and we would have been a bit frustrated."
After restoration, all consoles will be banned with strict access restrictions in order to preserve the Mocr-2 room for all humanity, and this, for the future
"There was a door in the very back corner [of the simulation room] and we're putting that door back, "says Tetley. "They called the simulator supervisor's backup door – because the emotions were so entrenched between the flight controllers and the simulators that he could come out the back door and escape . "
Even in recent years, visitors to the Mission Control Floor have been able to sit down and play the role of flight director (I admit that during a previous visit, a few years ago, I had already done it). After restoration, all consoles will be banned with strict access restrictions in order to preserve the Mocr-2 room for all humanity, and this, in the future. Instead, visitors will see the room through the glass of the VIP viewing gallery at the back, as they watched a real mission unfold.
Once completed, and as part of the first moon landing celebrations, the last people who will have the chance to sit on the consoles will be the controllers of the original mission. They will be photographed sitting at their workstation to keep track of their contribution to manned spaceflight.
Tetley says it's always a pleasure to see them again in the room where they wrote the story.
"They're like kids in a candy store," says Tetley. "They just smile, remembering what they've done here, it's very moving for me to see them and thank them for what we do."
Join more than 900,000 Future fans by loving us on Facebookor follow us on Twitter or Instagram.
If you liked this story, sign up for the weekly newsletter on the features of bbc.comcalled "If you only read 6 things this week". A selection of BBC Future stories, Culture, Capital and Travel, handpicked, delivered to your inbox every Friday.