SOLID ROCKET MOTOR (SRM) FACT SHEET

On November 7, 2023 the California Science Center will continue Go for Stack with the lifting 
and mating of two large Solid Rocket Motors (SRMs).

Each Solid Rocket Motor will be lifted by a 450-foot-tall crane and mated to an Aft Skirt, already 
installed in the Shuttle Gallery of the future Samuel Oschin Air and Space Center; then Forward 
Assemblies will be mated to the top. Once stacked, these elements will complete the Solid 
Rocket Boosters (SRBs).

The SRMs are the propulsive element and comprise the largest part of the Solid Rocket Boosters.

At the launch site, each SRB was attached to the mobile launcher platform at the Aft Skirt by 
four hold-down studs, with frangible nuts that were severed at liftoff. Then the External Tank 
was attached to the SRB Forward Skirts followed by the Orbiter, Endeavour. At the Samuel 
Oschin Air and Space Center, the Aft Skirts are fastened to the seismic isolator.

During the Space Shuttle Program, twin 15-story reusable Solid Rocket Boosters produced more 
than 6-million pounds of thrust - the majority of what was needed to lift a shuttle off the launch 
pad. The SRBs would ignite only after the Space Shuttle Main Engines were at full thrust, and 
flames would shoot down the interior of the SRB at liftoff to ignite the propellant. They could 
not be turned off once ignited.

Flight History:

Components of these two Solid Rocket Motors flew on a combined 81 space shuttle flights and 
32 static tests, dating back to STS-5 in 1982, the fifth NASA Space Shuttle mission and the fifth 
flight of the Space Shuttle Columbia. The last use of a component was for STS-133, the last 
flight of Discovery.

Solid Rocket Motor Stats: 

• Diameter: 12 feet 2 inches (146 inches)
• Length: 116 feet (1,392 inches) - Equivalent to the length of three school buses
• Weight: 104,000 pounds each
• Each SRM contained approximately 1.1 million pounds of polybutadiene acrylonitrile (PBAN) copolymer propellant that has the consistency of a pencil eraser.
• Each SRM attaches to its Aft Skirt using a tang and clevis joint with 177 1-inch-diameter pins (plus 3 similar index pins). 
• The Forward Assembly attaches to the top of the SRM using a tang and clevis joint with 195 1-inch-diameter pins.
• All connections used at the Samuel Oschin Air and Space Center will be identical to flight except that the hold-down studs are 116 inches long rather than 31 inches long. 

The SRMs are the final major space shuttle element to arrive at the California Science Center
and will be part of Endeavour’s ready-to-launch vertical display.