A cylindrically-shaped hybrid rocket engine solid fuel grain defines an axial combustion port. A fuel grain material comprises a compounded blend of thermoplastic fuel and aluminum. The fuel grain comprises fused stack layers, each layer comprising a plurality of fused abutting concentric beaded structures arrayed to define the combustion port; the port exhibits a rifling pattern or rifling inducing geometry along the port wall. When an oxidizer is introduced into the combustion port combustion occurs along the exposed port wall. Each beaded structure defines a geometry that increases the combustion surface area while inducing a vortex flow of oxidizer and fuel gas. As each layer ablates, an abutting layer exhibiting a similar geometry, is revealed, undergoes a gas phase change, and ablates. This process repeats and persists until oxidizer flow is terminated or the fuel grain material is exhausted. The fuel grain may be manufactured by an additive manufacturing process.

A cylindrically-shaped hybrid rocket engine solid fuel grain defines an axial combustion port. A fuel grain material comprises a compounded blend of thermoplastic fuel and aluminum. The fuel grain comprises fused stack layers, each layer comprising a plurality of fused abutting concentric beaded structures arrayed to define the combustion port; the port exhibits a rifling pattern or rifling inducing geometry along the port wall. When an oxidizer is introduced into the combustion port combustion occurs along the exposed port wall. Each beaded structure defines a geometry that increases the combustion surface area while inducing a vortex flow of oxidizer and fuel gas. As each layer ablates, an abutting layer exhibiting a similar geometry, is revealed, undergoes a gas phase change, and ablates. This process repeats and persists until oxidizer flow is terminated or the fuel grain material is exhausted. The fuel grain may be manufactured by an additive manufacturing process.

A multi-pulse gas generator includes a pressure vessel, an outer propellant arranged in the pressure vessel and which has a tubular shape, an intermediate propellant arranged inside the outer propellant and which has a tubular shape, an inner propellant arranged inside the intermediate propellant and which has a tubular shape, an internal structure arranged inside the inner propellant and fixed to the pressure vessel, a first barrier membrane arranged between the outer propellant and the intermediate propellant so as to isolate the outer propellant and the intermediate propellant from each other, and a second barrier membrane arranged between the intermediate propellant and the inner propellant so as to isolate the intermediate propellant and the inner propellant from each other. The outer propellant is supported on its outer surface by the pressure vessel. The inner propellant is supported on its inner surface by the internal structure.

A hybrid rocket solid fuel grain having a cylindrical shape and defining a center port is additive manufactured from a compound of thermoplastic fuel and passivated nanocomposite aluminum additive. The fuel grain comprises a stack of fused layers, each layer formed as a plurality of fused abutting concentric circular beaded structures arrayed to define a center port. During operation, an oxidizer is introduced along the center port, with combustion occurring along the exposed port wall. Each circular beaded structure defines geometry that increases the surface area available for combustion. As each layer ablates the next abutting layer, exhibiting a similar geometry, is revealed, undergoes a gas phase change, and ablates. This process repeats and persists until oxidizer flow is terminated or the fuel grain material is exhausted. To safely achieve this construction, a fused deposition additive manufacturing apparatus, modified to shield the nanocomposite material from the atmosphere, is used.

A hybrid rocket solid fuel grain having a cylindrical shape and defining a center port is additive manufactured from a compound of thermoplastic fuel and passivated nanocomposite aluminum additive. The fuel grain comprises a stack of fused layers, each layer formed as a plurality of fused abutting concentric circular beaded structures arrayed to define a center port. During operation, an oxidizer is introduced along the center port, with combustion occurring along the exposed port wall. Each circular beaded structure defines geometry that increases the surface area available for combustion. As each layer ablates the next abutting layer, exhibiting a similar geometry, is revealed, undergoes a gas phase change, and ablates. This process repeats and persists until oxidizer flow is terminated or the fuel grain material is exhausted. To safely achieve this construction, a fused deposition additive manufacturing apparatus, modified to shield the nanocomposite material from the atmosphere, is used.

A rocket motor (20) includes a nozzle (22) and a solid propellant section (24) in communication with the nozzle. The solid propellant section includes a first energetic grain layer (38, 32) that has a top surface and a bottom surface, and a second energetic grain layer (40, 44) that has a top surface and a bottom surface. The second layer is located on top of the first layer. The bottom surface of the second energetic grain layer partially abuts the top surface of the first energetic grain layer, and the bottom surface of the second energetic grain layer and the top surface of the first energetic grain layer define a region (46, 48) therebetween. A powder energetic (49) is disposed in the region.

A rocket motor (20) includes a nozzle (22) and a solid propellant section (24) in communication with the nozzle. The solid propellant section includes a first energetic grain layer (38, 32) that has a top surface and a bottom surface, and a second energetic grain layer (40, 44) that has a top surface and a bottom surface. The second layer is located on top of the first layer. The bottom surface of the second energetic grain layer partially abuts the top surface of the first energetic grain layer, and the bottom surface of the second energetic grain layer and the top surface of the first energetic grain layer define a region (46, 48) therebetween. A powder energetic (49) is disposed in the region.

A solid rocket motor includes a propellant grain and a barrier shielding at least a portion of the grain. The barrier is impermeable to water, oxygen, nitrogen, and volatile solid propellant species.

A solid rocket motor includes a propellant grain structure defining an axial bore and a vortex inducing feature.

A solid rocket motor includes a first solid propellant and a second solid propellant at least partially surrounding the first solid propellant. The second solid propellant is resistant to fragment impact and the first solid propellant has a higher impulse than the second solid propellant.