Solid rocket motors including flight termination systems, and related multi-stage solid rocket motor assemblies and methods

A solid rocket motor, comprising:

• a skirt structure;
• a pressure vessel discrete from and contained within the skirt structure;
• a nozzle assembly connected to the skirt structure and an aft end of the pressure vessel;
• a solid propellant structure within the pressure vessel;
• a bore longitudinally extending through the solid propellant structure;
• a slot in communication with an aft end of the bore and exhibiting a radial end longitudinally proximate an aft end of the pressure vessel, the slot outwardly tapering from a location along the bore more longitudinally distal from the aft end of the pressure vessel to the radial end thereof;
• and
• a flight termination system comprising:
• a first shaped charge overlying one or more of the skirt structure and the pressure vessel, the first shaped charge positioned over and laterally aligned with the radial end of the slot and configured to effectuate ignition of the solid propellant structure at the aft end of the bore;
• and
• a second shaped charge overlying the skirt structure and spaced apart from the first shaped charge, the second shaped charge configured and positioned to effectuate a reduction in an ability of the pressure vessel to withstand a change in internal pressure.

A multi-stage rocket motor assembly, comprising:

• an outer housing;
• and
• a plurality of stages in a stacked arrangement within the outer housing, at least one stage of the plurality of stages comprising:
• a pressure vessel;
• a solid propellant structure within the pressure vessel;
• a bore longitudinally extending through the solid propellant structure;
• a slot in communication with an end of the bore and exhibiting a radial end proximate a sidewall of the pressure vessel, the radial end of the slot longitudinally extending across less than an entirety of the bore, and an outer boundary of the slot tapering toward the bore from the radial end of the slot;
• and
• a flight termination system overlying the pressure vessel and comprising at least one shaped charge positioned over and aligned with the radial end of the slot and configured to effectuate ignition of an inner portion of the solid propellant structure at the bore and a reduction in an ability of the pressure vessel to withstand a change in internal pressure.

A method of destroying a launch vehicle in flight, comprising:

• initiating at least one shaped charge of a flight termination system of a solid rocket motor of the launch vehicle to pressurize the solid rocket motor and weaken a pressure vessel thereof to fragment a solid propellant structure of the solid rocket motor into multiple pieces, the solid rocket motor comprising:
• the pressure vessel;
• the solid propellant structure within the pressure vessel;
• a bore longitudinally extending through the solid propellant structure;
• a slot in communication with an end of the bore and exhibiting a radial end proximate a sidewall of the pressure vessel, the radial end of the slot longitudinally extending across less than an entirety of the bore, and an outer boundary of the slot tapering toward the bore from the radial end of the slot;
• and
• the flight termination system overlying the pressure vessel and comprising at least one shaped charge positioned over and laterally aligned with the radial end of the slot and configured to effectuate ignition of an inner portion of the solid propellant structure at the bore and a reduction in an ability of the pressure vessel to withstand a change in internal pressure.