“Aft Skirts” Fact Sheet

The placement of the Solid Rocket Booster Aft Skirts on July 20, 2023, will serve as the 
foundation of the vertical shuttle stack.

A total of two Aft Skirts will be placed on top of the seismic isolator pad in the Shuttle 
Gallery of the Samuel Oschin Air and Space Center.

The two Aft Skirts flew on a combined 15 space shuttle flights, dating back to STS-3 in 
1982, the third mission. 

One of the skirts lifted off 11 times, last flying with Endeavour in 2010 (STS-130).

Aft Skirt Stats: 

• Diameter: 18 feet (222 inches) at the base and 12 feet (146 inches) at the top
• Width: 18 feet (222 inches)
• Height: 7.6 feet (92.3 inches)
• Weight: 13,000 pounds

Each Aft Skirt will be held in place by 4 hold-down studs.

Each stud:

• Is made of a heavy and durable nickel-chromium-based superalloy, known as 
• “Inconel”
• Weighs approximately 900 pounds
• Is 9 feet in length
• Must be carefully and expertly fastened
• Our engineers only have 1/10th of an inch worth of give to work with. That’s about the width of a nickel.

Following the placement and securement of the Aft Skirts, two Solid Rocket Motors will 
later be stacked atop the skirts, followed by the Forward Assemblies. Combined, these 
elements will form the Solid Rocket Boosters.