Abstract: An injector for a liquid rocket engine includes an array of injector elements. Each injector element includes a central passage and a plurality of peripheral transverse passages. The central passages are configured to provide axial injection flow and the peripheral transverse passages are configured to provide swirl injection flow about the axial injection flow. A portion of the injector elements are configured to provide the swirl injection flow in a clockwise direction and another portion of the injector elements are configured to provide the swirl injection flow in a counter-clockwise direction. The injector elements are arranged to form a plurality of circumferential rows. The injector elements of each individual circumferential row are either all of the clockwise direction or all of the counter-clockwise direction. At least one of the circumferential rows is of the clockwise direction and at least one of the circumferential rows is of the counter-clockwise direction.

Abstract: An injector element for a liquid propellant rocket engine includes an oxidizer conduit, a central cavity that is fluidly coupled with the oxidizer conduit downstream of the oxidizer conduit, a first annulus that at least partially surrounds the oxidizer conduit and is fluidly coupled with an ignition fluid supply downstream of the ignition fluid supply, and a second annulus that at least partially surrounds the oxidizer conduit and is fluidly coupled with a fuel supply downstream of the fuel supply. The second annulus is fluidly coupled between the first annulus and the central cavity.

Abstract: A Hall thruster includes an annular discharge region and an annular cathode concentric to the annular discharge region.

Abstract: A liquid propellant rocket engine includes a pump that is disposed along a central axis. The pump includes a purge system, a collection annulus in fluid communication with the purge system, and a drain. The collection annulus has an outer diameter wall, an inner diameter wall, and an end wall. The end wall defines an annular channel that has a channel depth that varies circumferentially. The drain opens to the collection annulus. At the drain, the annular channel has a lowest point at which the channel depth is maximum depth.

Abstract: A solid rocket propellant includes a binder that has hydroxyl-terminated polybudadiene (HTPB) with a curative that is selected from isocyanate-terminated polyether, isocyanate-terminated polysiloxane, or combinations thereof.

Abstract: A turbopump includes an impeller (22) that is rotatable about an axis (A). A discharge collector (28) is located radially outward of the impeller. A passage (30) fluidly connects the impeller to the discharge collector. The passage is curved.

Abstract: A catalytic thruster includes a reaction chamber that extends between first and second opposed chamber ends. The first chamber end includes a thermal standoff cup. There is a catalyst bed in the reaction chamber, and a feed tube extends into the reaction chamber through the thermal standoff cup.

Abstract: A power converter includes a first rectifier circuit having a pair of first rectifier circuit output terminals and a second rectifier circuit having a pair of second rectifier circuit output terminals, a snubber circuit comprising a first diode and a first capacitor connected to each other at a first node and connecting the pair of first rectifier circuit output terminals, a second diode and a second capacitor connected to each other at a second node and connecting the pair of second rectifier circuit output terminals, a third diode connecting the first node to one of the pair of second rectifier output terminals, and a fourth diode connecting the second node to one of the pair of first rectifier output terminals.

Abstract: A pump includes an axial inducer. The axial inducer includes a housing that has an internal surface that defines an axial fluid passage. A rotor is disposed about a central axis in the fluid passage. The rotor includes at least one blade that defines at least one blade tip. The internal surface of the housing defines a plurality of grooves adjacent the at least one blade tip. The grooves are elongated in a circumferential direction.

Abstract: A rocket engine includes a copper alloy combustion chamber, a non-copper weld transition ring welded to the copper alloy combustion chamber, and an injector assembly welded to the non-copper weld transition ring. The engine can be manufactured by forming the copper alloy combustion chamber using additive manufacturing, welding the non-copper weld transition ring to the copper alloy combustion chamber, and welding the injector assembly to the non-copper weld transition ring.

Abstract: An impedance measurement circuit includes a signal injector having a voltage input and a voltage output, a controllable switch, and a voltage drop device connected in parallel with the controllable switch between the voltage input and the voltage output. The voltage output is connected to a load. A voltage sensor is configured to measure a voltage across the load. A current sensor is configured to measure a current draw of the load. A computing device is configured to determine an impedance of the load at a frequency based on the measured voltage and the measured current. The computing device controls the switch based on the frequency.

Abstract: A latch valve includes a ferromagnetic shell, a ferromagnetic pole, a permanent magnet disposed within the ferromagnetic shell, an electromagnet disposed within the ferromagnetic shell, a seal, and a magnetic plunger disposed within the ferromagnetic shell. The ferromagnetic shell, the permanent magnet, the electromagnet and the magnetic plunger are configured in a magnetic circuit, and the magnetic plunger is configured to selectively compresses the seal based on a force produced by the magnetic circuit.

Abstract: A method for enhanced validation of an entity associated with a COF token includes: storing at least transaction data, a token requester identifier (TRJD), and a COF token identifier; receiving payment credentials, wherein the payment credentials include at least a COF-specific payment token; generating a transaction message, wherein the transaction message is formatted based on one or more standards and includes at least a plurality of data elements including at least a first data element configured to store the COF-specific payment token, a second data element configured to store the COF token identifier, a third data element configured to store the TRID, and one or more additional data elements configured to store the transaction data; and electronically transmitting the generated transaction message to a financial institution via a payment network.

Abstract: A liquid propellant rocket engine includes a main turbo-pump and a boost turbo-pump. The main turbo-pump has a main pump with an outlet that is fluidly coupled with a supply line. The boost turbo-pump includes a housing, a rotor, a boost pump, and a turbine. The boost pump includes a first portion of the housing and a first portion the rotor. The turbine includes a second portion of the housing and a second portion of the rotor. The turbine has turbine blades attached to the second portion of the rotor and an inlet fluidly coupled with the supply line. The turbine has a plurality of circumferentially disposed feed lines defined by the second portion of the housing and not the first portion of the housing. The feed lines are fluidly coupled between the inlet and the turbine blades. The feed lines have an acute angle turn.

Abstract: An engine start system includes a facility that has a ground based hydraulic pressurization system and a combustor of a liquid propellant rocket engine. The engine is fluidly coupled to the ground based hydraulic pressurization system. The liquid propellant rocket engine is operably detachable from the ground based hydraulic pressurization system.

Abstract: A latch valve includes a ferromagnetic shell, a ferromagnetic pole, a permanent magnet, an electromagnet, and a ferromagnetic plunger that is disposed within the ferromagnetic shell.

Abstract: A liquid propellant rocket engine includes a combustion chamber that has a throat and a nozzle aft of the throat. The nozzle has a first nozzle section adjacent the throat and a second nozzle section aft of the first nozzle section. The first nozzle section includes active cooling features and the second nozzle section excludes any active cooling features. The first nozzle section is operative via at least the active cooling features to form a condensate that passively cools the second nozzle section.

Abstract: A propulsion system includes at least one group of electric thrusters that are spatially distributed in a multi-axis system. A controller is in communication with each of the electric thrusters. The controller is configured to differentially throttle the thrusts of the electric thrusters with respect to propulsion force about two axes of the multi-axis system.

Abstract: A turbopump includes a slinger that has a first section and a second section. The first and second sections are disposed substantially radially in a fluid circuit. The second section is downstream of, and radially inward of, the first section. A housing is located downstream and adjacent to the first section of the slinger and radially outward of the second section of the slinger.

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