UPDATE: As we enter the final two months of Space Shuttle Endeavour’s current horizontal display, the California Science Center has continued its “Go for Stack” process, which will assemble the ship vertically, with two towering additions.
On November 7, the museum lifted a pair of solid rocket motors into the future Samuel Oschin Air and Space Center and then secured them to the previously placed aft skirts (which you can read more about below). We had a chance to step into the construction site later that week to photograph the two 116-foot long boosters—and the scale is absolutely staggering.
This won’t even be the highest point of the completed shuttle stack: The cone-shaped forward assemblies, which are currently visible just across from the stack, will soon be placed on top of the motors, and then the orange-red external fuel tank between them. (The shuttle itself will finally follow after it goes off display at the start of 2024.) While the public isn’t allowed to peer into the construction pit, you can catch a glimpse of the rockets towering above the concrete walls—but you’ll have to be quick, as they’ll soon be encased in scaffolding for protection.
Our original story from July 21, 2023 appears below.
While suspended in the air, the 18-foot-wide, 13,000-pound metal rings don’t look like much. But after the aft skirts—the conical bases of space shuttle-launching rocket boosters—have been lowered into a pit of concrete and dirt at the California Science Center, it doesn’t take much imagination to start seeing the rest of the picture. Like stumbling upon a giant’s shoes, these aft skirts tease the staggering size of what will eventually fill them.
After 123 million miles logged around the Earth, Space Shuttle Endeavour has been on public display for the past decade inside a temporary tent at the Exposition Park museum. But the California Science Center has much bigger plans for the retired NASA spacecraft: the Samuel Oschin Air and Space Center, a free-to-visit expansion that’ll assemble Endeavour, an orange external fuel tank and a pair of solid rocket boosters in a vertical, ready-to-launch position—the only configuration of its kind in the world.
On Thursday, the museum began the six-month-long process of assembling all of these pieces. Dubbed “Go for Stack,” the installation kicked off with a pair of 8-foot-tall aft skirts that were trucked over to the construction site and then lifted and lowered via crane into their permanent position at the base of the under-construction building. Next up will be the 116-foot-fall solid rocket motors, followed by the 27-foot-tall forward assemblies that top them. Then, ET-94, the massive orange external fuel tank visible just outside of the current Endeavour exhibition, will be placed into pit. And finally, the space shuttle itself will be moved over to the site, raised vertically via crane and then lifted and lowered into the unfinished building. After that, the rest of the building will be constructed around the complete stack.
This does mean that Space Shuttle Endeavour will go off exhibit after December 31, 2023, and it won’t be seen again until the Samuel Oschin Air and Space Center debuts in “several years” (the museum hasn’t set an opening date yet, but estimated a three-year construction period at the time of the building’s 2022 groundbreaking).
The wait seems like it’ll be worth it, though: The expansion will double the Science Center’s display space, with 100 exhibits across three level of galleries dedicated to flight and the exploration of the universe. The completed stack will have multiple viewing points and measure in around 20 stories, which for reference is about the same height as the former Tower of Tower at Disneyland.
We were invited to watch this week as crews trucked in each aft skirt and carefully secured them to a towering crane on the edge of the construction site. They were then individually lifted over the maze of scaffolding and lowered into a pit, where they were secured onto a seismic isolator pad. Each will be permanently held in place by four 9-foot studs that weigh in at 900 pounds—and need to be so precisely placed that engineers only have wiggle room equivalent to the thickness of a nickel.
Thinking of each part of the stack—particularly the space shuttle itself—undergoing this process seemed harrowing to us, but California Science Center president and CEO Jeff Rudolph explained that this actually takes advantage of a pretty tried-and-true formula. The museum had considered constructing the new building first and then tilting the put-together shuttle stack from horizontal to vertical, which is similar to how SpaceX puts its Dragon spacecraft on the launchpad. But that would leave a gaping hole in the side of the building, and the museum determined that wasn’t really feasible. Moreover, tilting the entire stack would require a separate load analysis for each intermediate position. Instead, the plan they landed on is similar to the process that was used for all 135 space shuttle missions, albeit with more cranes and scaffolding, and takes advantage of the same basic engineering.
You can check out our footage of the aft skirt installation as well as more photos below.