Pulsed rocket motors

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A pulsed rocket motor is typically defined as a multiple pulse solid propellant rocket motor. This design overcomes the limitation of solid propellant motors that they cannot be easily stopped and reignitied. The pulse rocket motor allows the motor to be burned in segments (or pulses) that burn until completion of that segment. The next segment (or pulse) can be ignited on command by either an onboard algorithm or in pre-planned phase. All of the segments are contained in a single rocket motor case as opposed to staged rocket motors.

The pulsed rocket motor is made by pouring each segment of propellant separately. Between each segment is a barrier that prevents the other segments from burning until ignited. At ignition of a second pulse the burning of the propellant generally destroys the barrier. Both hard and soft barriers technologies exist. Since the 1980's the development of soft barriers have made the deployment of tactical missiles with pulse rocket motors possible.

The benefit of the pulse rocket motor is that by the command igntition of the subsequent pulses, near optimal energy management of the propellant burn can be accomplished. Each pulse can have different thrust level, burn time, and achieved specific impulse depending on the type of propellant used, its burn rate, its grain design, and the current nozzle throat diameter.

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