Abstract: A combustible element includes regions of fuel material interspersed with regions of oxidizer material. The element may be made by additive manufacturing processes, such as three-dimensional printing, with the fuel material regions and the oxidizer material regions placed in appropriate locations in layer of the combustible element. For example, different extruders may be used to extrude and deposit portions of a fuel filament and an oxidizer filament at different locations in each layer of the combustible element. The combustible element may define a combustion chamber within the element, where combustion occurs when the combustible element is ignited. The fuel material and the oxidizer material may be selected, and their relative amounts may be controlled, such that desired relative amounts of fuel and oxidizer are present for combustion with desired characteristics, such as combustion rate.

Abstract: A method of making an electrical connection includes soldering using channels in a receptacle to direct hot air (or another hot gas) to effect soldering where the electrical connection is to be made. The connection may be made between device electrical contacts of an electrical device, and other contacts, such as receptacle contacts of the receptacle. The connection may be a blind connection, one in which the connected ends of the contacts are hidden or unable to be directly physically accessed, when the connection is made. The electrical connection may be made between device contacts of an electrical device that is inserted into the receptacle, and receptacle electrical contacts that are part of the receptacle. The channels for directing the hot gas to where the soldering occurs may be parts of the receptacle, for example being produced during additive manufacture of the receptacle.

Abstract: A method of producing a propellant material element, such as an electrically-operated propellant material, includes extruding a propellant material through a heated nozzle. The nozzle may be heated to a temperature that is above the boiling point of a solvent that is part of the propellant material, yet is below a decomposition temperature of the propellant material. This allows some of the solvent to be driven off during the extruding process, while still preventing initiation of an energy-creating reaction within the material. The heating of the material in the extruding process, and especially the heating of the nozzle that the material is extruded through, may be controlled to remove an amount of solvent that results in the extruded material having desirable properties.

Abstract: An open-loop thermal control system and method for components that generate heat includes a reservoir for containing a pressurized working fluid, a first heat exchanger in thermal communication with the working fluid, a Joule-Thomson expansion valve in fluid communication with the reservoir, and a second heat exchanger in fluid communication with the valve. The first heat exchanger is configured to transfer heat from the components to the fluid in the reservoir. The valve is configured to expand the working fluid into a two-phase fluid having a primary use of cooling. The second heat exchanger is configured to receive heat from the components and receive the two-phase fluid. The second heat exchanger provides a single-phase working fluid for at least one secondary use before the working fluid is expelled from the thermal control system.

Abstract: A thruster has an additively-manufactured housing that includes an integrally-formed nozzle with a burst disk in it. The housing is part of a casing that surrounds and encloses a propellant that is burned to produce pressurized gases that burst the burst disk and produce thrust. The thruster may be placed in a receptacle that defines a recess for receiving the thruster. The receptacle also may be additively manufactured. The thruster and the recess both may be cylindrical, with the housing being closely fit with the cylindrical walls of the receptacle. This may allow some of the structural loads on the housing, such as loads produced by the combustion of the propellant, to be transferred to the adjoining walls of the receptacle. This enables the housing to have less structural strength than if it were to have to contain the pressure from the propellant all on its own.

Abstract: A projectile, such as a railgun-launched projectile, includes a single-piece body that is additively manufactured. The single piece body includes fuel within it, and one or more cavities for receiving an oxidizer. The body also defines one or more combustion chambers therein for combustion of the fuel and oxidizer as part of a divert thruster system. Thus the projectile is able to fully contain the divert thruster system within the single-piece body without using any hot gas seals as part of the system. The body may also define a cavity for receiving a pressurized fluid, used as part of a cold-gas attitude control system of the projectile. The body may also define passages between the pressurized fluid cavity and other parts of the attitude control system, such as valves and/or nozzles that are outside of the body, for example being aft of the one-piece body.

Abstract: A method of making an electrical connection includes soldering using channels in a receptacle to direct hot air (or another hot gas) to effect soldering where the electrical connection is to be made. The connection may be made between device electrical contacts of an electrical device, and other contacts, such as receptacle contacts of the receptacle. The connection may be a blind connection, one in which the connected ends of the contacts are hidden or unable to be directly physically accessed, when the connection is made. The electrical connection may be made between device contacts of an electrical device that is inserted into the receptacle, and receptacle electrical contacts that are part of the receptacle. The channels for directing the hot gas to where the soldering occurs may be parts of the receptacle, for example being produced during additive manufacture of the receptacle.

Abstract: An electrical device has device electrical contacts that are initially shunted together, to prevent accidental triggering or damage to the device, such as by electrostatic forces. The device is configured to be inserted into a receptacle, with parts of the receptacle disengaging the shunt and making electrical connection within the receptacle, such as with a shunt cutter. The receptacle may also include a pair of receptacle electrical contacts the electrically connect to the device electrical contacts. The configuration, where the shunt is only cut as part of the installation process, enables safer handling of initially-shunted devices, and can also facilitate making blind electrical connections. Making blind connection directly with parts of the receptacle also avoids the need to thread wires through the electrical receptacle and make electrical connections in another way.

Abstract: Microwave energy is used to ignite and control the ignition of electrically operated propellant to produce high-pressure gas. The propellant includes conductive particles that act as a free source of electrons. Incoming microwave energy accumulates electric charge in an attenuation zone, which is discharged in the form of dielectric breakdowns to create local randomly oriented currents. The propellant also includes polar molecules. The polar molecules in the attenuation zone absorb microwave energy causing the molecules to rapidly vibrate thereby increasing the temperature of the propellant. The increase in temperature and the local current densities together establish an ignition condition to ignite and sustain ignition of an ignition surface of the attenuation zone as the zone regresses without igniting the remaining bulk of the propellant.

Abstract: A method of additively manufacturing propellant elements, such as for rocket motors, includes partially curing a propellant mixture before extruding or otherwise dispensing the material, such that the extruded propellant material is deposited on the element in a partially-cured state. The curing process for the partially-cured extruded material may be completed shortly after the material is put into place, for example by the material being heated at or above its cure temperature, such that it finishes curing before it fully cools. The propellant material may be prepared by first mixing together, a fuel, an oxidizer, and a binder, such as in an acoustic mixer. After that mixing a curative may be added to the mixture. The propellant mixture may then be directed to an extruder (or other dispenser), in which the mixture is heated to or above a cure temperature prior to the deposition, and then deposited.

Abstract: Electrical ignition of electrically operated propellant in a gas generation system provides an ignition condition at an ignition surface between a pair of electrodes that satisfies three criteria of a current density J that exhibits a decreasing gradient along an axis normal to an ignition surface, is substantially constant across the ignition surface and exceeds an ignition threshold at the ignition surface. These criteria may be satisfied by one or more of an angled electrode configuration, a segmented electrode configuration or an additive to the electrically operated propellant that modifies its conductivity. These configurations improve burn rate control and consumption of the available propellant and are scalable to greater propellant mass to support larger gas generation systems.

Abstract: A satellite has thrusters that are integral parts of its frame. The frame defines cavities therein where thrusters are located. The thrusters may include an electrically-operated propellant and electrodes to activate combustion in the electrically-operated propellant. The frame may be additively manufactured, and the propellant and/or the electrodes may also be additively manufactured, with the frame and the propellant and/or the electrodes also being manufactured in a single process. In addition the thrusters may have nozzle portions through which combustion gases exit the thrusters. The thrusters may be located at corners and/or along edges of the frame, and may be used to accomplish any of a variety of maneuvers for the satellite. The satellite may be a small satellite, such as a CubeSat satellite, for instance having a volume of about 1 liter, and a mass of no more than about 1.33 kg.

Abstract: A thruster includes multiple segments of electrically-operated propellant, electrodes for igniting one or a few of the electrically-operated propellant segments at a time, and a propellant feeder for moving further propellant segments into engagement with the electrodes. The segments may be configured to provide equal increments of thrust, or different amounts of thrust. The segments may each include an electrically-operated propellant material surrounded by a sealing material, so as to keep the propellant material away from moisture and other contaminants (and/or the vacuum of space) before each individual segment is to be used. The thruster may be included in any of a variety of flight vehicles, for example in a small satellite such as a CubeSat satellite, for instance having a volume of about 1 liter, and a mass of no more than about 1.33 kg.

Abstract: A device may include an electrically-operated propellant or energetic gas-generating material, additively manufactured together with electrodes for producing a reaction in the material. The device may also include a casing that is additively manufactured with the other components. The additive manufacturing may be accomplished by extruding or otherwise depositing raw materials for the different components where desired. The electrodes may be made of a conductive polymer material, for example using an electrically-conductive fill in a polymer.

Abstract: A method of producing a propellant material element, such as an electrically-operated propellant material, includes extruding a propellant material through a heated nozzle. The nozzle may be heated to a temperature that is above the boiling point of a solvent that is part of the propellant material, yet is below a decomposition temperature of the propellant material. This allows some of the solvent to be driven off during the extruding process, while still preventing initiation of an energy-creating reaction within the material. The heating of the material in the extruding process, and especially the heating of the nozzle that the material is extruded through, may be controlled to remove an amount of solvent that results in the extruded material having desirable properties.

Abstract: A hybrid rocket motor includes a solid fuel element, and an oxidizer tank containing an oxidizer. The solid fuel element adjoins and at least partially defines a combustion chamber in which the solid fuel and the oxidizer are burned, to produce thrust from the hybrid rocket motor. The oxidizer tank is at least partially within the combustion chamber, and the entire oxidizer tank may be within the combustion chamber. The oxidizer tank may be protected by an insulating material, which may also serve as a structural material that contains the pressure of the oxidizer. The insulating material and the fuel material may both be polymer-based materials, although they may be different materials having different characteristics, for example including different additives to the same polymer material. The fuel element and the oxidizer tank may be made by additive manufacturing processes, for example by adding different materials in different locations.

Abstract: A device is provided. The device includes at least one SMM component fabricated from an SMM. The SMM component is configured to change shape in response to receiving a stimulus. The SMM component is also configured to deploy from a device body of the device allowing the device to change shape in an advantageous way. A method implemented by a device is also provided. The method includes changing a shape of an SMM component of the device in response to receiving a stimulus. The SMM component is fabricated from an SMM. The method also includes deploying the SMM component from a device body of the device allowing the device to change shape in an advantageous way.

Abstract: A motor assembly is provided for use with projectiles, such as munitions, having relatively low length to diameter ratios. The motor assembly has an aerospike nozzle and a casing disposed about the aerospike nozzle, where interior aerospike volume contains propellant and where walls of both the cowl of the casing and of the aerospike nozzle jointly define a combustion chamber.

Abstract: An open-loop thermal control system and method for components that generate heat includes a reservoir for containing a pressurized working fluid, a first heat exchanger in thermal communication with the working fluid, a Joule-Thomson expansion valve in fluid communication with the reservoir, and a second heat exchanger in fluid communication with the valve. The first heat exchanger is configured to transfer heat from the components to the fluid in the reservoir. The valve is configured to expand the working fluid into a two-phase fluid having a primary use of cooling. The second heat exchanger is configured to receive heat from the components and receive the two-phase fluid. The second heat exchanger provides a single-phase working fluid for at least one secondary use before the working fluid is expelled from the thermal control system.

Abstract: A spacecraft, such as a satellite, uses a shape memory polymer actuator to deploy one or more deployable parts. The shape memory polymer actuator may be formed integrally with a deployable part and/or with a fuselage or other structure of the spacecraft, with the shape memory polymer actuator being for example a relatively thin portion of the shape memory polymer material of the integral structure. The shape memory actuator allows deployment of the deployable part(s) upon heating of the shape memory polymer material of the actuator, such as after the satellite has been launched into space. The heating may be caused by a heat source that is part of the spacecraft itself, or may be merely the result of exposing the spacecraft to solar heating after launch. The deployable part of the spacecraft may include any of a wide variety of parts that are used after launch.