Booster separation motor
The booster separation motor on the Space Shuttle is a relatively small rocket motor that separates the reusable solid rocket motors from the shuttle before the shuttle leaves the atmosphere. This separation occurs after about 2 minutes of burn time of the reusable solid rocket motors, and firing of the booster separation motors takes less than a second. The Space Shuttle Solid Rocket Booster separation rocket motors must be used in conjunction with the release of the motors from the External Tank (ET).
The booster separation motors are produced by ATK Launch Systems Group, part of Alliant Techsystems (ATK) Inc., at their facility in Brigham City, Utah. Booster separation motors weigh 177 pounds when loaded with propellant. Each is approximately 31 inches long and 12.8 inches in diameter. About two minutes into a space shuttle flight, 16 of these small, but powerful, motors are fired simultaneously for 1.2 seconds. This provides the precise thrust required to safely separate the spent boosters from the space shuttle's external tank and orbiter.
Eight booster separation motors are attached to each of the shuttle's two reusable solid rocket boosters, four on the forward skirt and four on the aft skirt. The booster separation motors in each cluster are ignited while traveling through the atmosphere at more than 3,000 mph and an altitude of approximately 24 nautical miles.