— With the end of 2023 comes the end of an endeavor — or rather Endeavour — as the retired NASA space shuttle goes off public view for the next few years.

The California Science Center in Los Angeles has exhibited OV-105, better known as the orbiter Endeavour, since Oct. 30, 2012. The 11-year exhibition, which was housed in the center's specially-built Samuel Oschin Pavilion, offered unmatched access to the spacecraft, as the public could not only walk around Endeavour, but also under it, as the vehicle was displayed in the horizontal atop raised mounts.

Now, the science center is preparing to take Endeavour vertical — standing it up with a pair of solid rocket boosters and an external tank like it was last seen on the launch pad. The new 20-story-tall display will be the highlight inside the new Samuel Oschin Air and Space Center, which is under construction adjacent to the main science center building in L.A.'s Exposition Park.

Though the work to stack Endeavour is expected to be completed in early 2024, the building and its exhibits will not be ready for public visitors for a few more years to come, during which there will be no public access to the space shuttle.

The last visitors to see Endeavour on exhibit will be those who leave the science center when it closes on Sunday (Dec. 31) at 5:00 p.m. PST.

"You could be very intimate with Endeavour by being able to walk under her," Dennis Jenkins, the project manager for the California Science Center's space shuttle display, said in an interview with collectSPACE. "I'm going to miss how Endeavour is right now."

"That said, how she's going to be when we reopen in a couple of years will be fantastic. So we are trading an extremely interesting exhibit for an even more interesting exhibit," he said.

The science center did not count every person who came to see Endeavour, but during the time that the pavilion has been open, nearly 20 million people came to the center and a majority saw the space shuttle as part of their visit. In addition to families and school groups touring the pavilion, Endeavour became the backdrop for the annual Yuri's Night world space party and the centerpiece for a number of Hollywood premieres (including the 2013 Blu-ray and DVD release of "Star Trek Into Darkness" with director J.J. Abrams and the Leonard Nimoy in attendance, as well as the the television series "Extant" with Halle Berry).

The pavilion even made into a couple of movies itself. Luke Wilson appeared opposite Endeavour in the 2014 short film "Satellite Beach," directed by his brother Andrew Wilson. And the space shuttle was taken out of retirement as part of the plot of Roland Emmerich's 2022 action movie "Moonfall."

Other visitors included a number of Endeavour's former crew members, who came to see their previous ride into space.

"I got an email just recently from an astronaut saying that he and his family had come to see Endeavour one last time before it went off exhibit," Jeffrey Rudolph, president and chief executive officer of the California Science Center, said in an interview with collectSPACE.

Regardless of who they were, most visitors shared the same reaction when first seeing the black and white orbiter sitting just beyond their arm's reach.

"I especially liked watching the kids, but everybody had the same awe and mouths dropping open when they first walked in and saw it. That's got to be the thing that will stick with me," said Rudolph.

While space shuttle Endeavour is off view, the California Science Center will have a temporary exhibit previewing the vertical display coming to the Samuel Oschin Air and Space Center, including a few space shuttle artifacts.

The other two flown orbiters, Discovery and Atlantis, remain open on exhibit at the Smithsonian National Air and Space Museum's Steven F. Udvar-Hazy Center in Chantilly, Virginia and NASA's Kennedy Space Center Visitor Complex in Florida, respectively. The prototype Enterprise is on exhibit at the Intrepid Museum in New York and the Shuttle Carrier Aircraft that flew Endeavour to Los Angeles is open for tours at Space Center Houston in Texas.