“Go for Stack” Fact Sheet 

The shuttle stacking process, which will take approximately six months, will begin with 
the Aft Skirts installation on July 20, 2023, and will be marked by seven important 
milestones:

1. The installation of the Solid Rocket Booster Aft Skirts, which are 8 feet in height and 18 feet in diameter. These form the base of the Solid Rocket Boosters. 
2. The stacking of two Solid Rocket Motors directly above the Aft Skirts, each roughly 116 feet (1,389 inches) in height and 12 feet (146 inches) in diameter.
3. The installation of the Solid Rocket Booster Forward Assemblies that form the top of each booster. The Forward Assemblies are 27 feet (329 inches) long and 146 inches in diameter at the base. 
4. The movement and lift of “ET-94,” the External Tank.
5. Space Shuttle Endeavour’s final move to the site of the future Samuel Oschin Air and Space Center.
6. The Orbiter’s lift into place by an 825-ton-capacity crane with a 425-foot long boom. 
7. The mating of Endeavour with the rest of the space shuttle stack.

Shuttle Stack Stats: 

Combined, the total weight of the shuttle stack will be 502,000 pounds. 

• The Solid Rocket Boosters, also known as “SRBs,” each weigh 
• 125,000 pounds.
• Together, they will weigh 250,000 pounds.
• The External Tank, known as “ET-94," weighs 76,000 pounds.
• The Orbiter, Endeavour, weighs 176,000 pounds.

The shuttle stack will be secured to a 1,800-ton concrete slab containing six seismic 
isolators. Once stacked, it will stand at 183 feet in height and 78 feet in width. 
Upon completion, Endeavour will be exhibited in an awe-inspiring ‘ready-to- launch’ 20-
story vertical display, complete with Solid Rocket Boosters and an External Tank, in 
what will be the world’s only authentic space shuttle stack.