The Space Shuttle Reusable Solid Rocket Motor (RSRM), built by Thiokol, is the largest solid motor ever flown and the first designed for reuse.  Two RSRMs are used on each Space Shuttle flight.  Each RSRM produces an average thrust of 2,600,000 pounds and burns for approximately 123.6 seconds.  At burn out the Space Shuttle has reached an altitude of 24 nautical miles and a velocity of more than 3,000 miles per hour.

Thiokol developed the RSRM to be reusable.  After the propellant is depleted the boosters separate from the orbiter and descend to the ocean with the aid of parachutes.  They float in a nozzle end down position until recovered and returned to Thiokol.  The cases are cleaned, inspected and reassembled for propellant casting.  The propellant is poured into four primary segments and cured.  A new nozzle and igniter is installed and the RSRMs are shipped back to the launch site. The steel case components of the RSRMs can be used 20 times.