Solid Rocket boosters
The Solid Rocket Boosters(SRB) are solid rockets that provide most of the main force or thrust (71 percent) needed to lift the space shuttle off the launch pad. In addition, the SRBs support the entire weight of the space shuttle orbiter and fuel tank on the launch pad.
The two SRBs provide the main thrust to lift the space shuttle off the pad and up to an altitude of about 150,000 feet. Each rocket booster is 149.16 feet long and 12.17 feet in diameter and SRB weighs approximately 1,300,000 pounds at launch. The propellant for each solid rocket motor weighs approximately 1,100,000 pounds. The inert weight of each SRB is approximately 192,000 pounds.
The main parts of solid rocket motor are:
• Solid rocket motor
• Solid propellant (see solid propellants)
• Thrust control system
• Self-destruct mechanism
Because the SRBs are solid rocket engines, once they are ignited, they cannot be shut down. Therefore, they are the last component to light at launch.