A thruster system includes a tank for holding liquid propellant, a catalyst bed connected with the tank and operable to decompose the liquid propellant and generate a gas, a plenum connected with the catalyst bed for receiving the gas, a heat exchanger connected with the plenum to cool the gas to a temperature below a threshold temperature and thereby generate a cooled gas, at least one thruster connected with the heat exchanger to receive the cooled gas, and at least one control valve between the heat exchanger and the at least one thruster controlling flow of the cooled gas to the thruster. At least one control valve includes a soft material valve seal.

Dual mode engine for propelling spacecraft, including combustion chamber having flange end, open nozzle end, and enclosed chamber portion extending therebetween, propellant tank in fluidic communication with combustion chamber, electronic controller, power source operationally connected to electronic controller, and fluid flow motivator operationally connected to electronic controller and connected in fluidic communication with propellant tank. Engine has chemical propulsion portion with propellant inlet port operationally connected to combustion chamber and disposed adjacent flange end, ignition trigger electrode positioned in combustion chamber adjacent propellant inlet port and operationally connected to electronic controller and operationally connected to power source propellant inlet port fluidically connected to tank electric propulsion portion with two electrodes ionizing propellant positioned in combustion chamber adjacent nozzle end, plurality of attitude control thrusters operationally connected to electronic controller and in fluidic communication with propellant tank, and plurality of valves, each fluidically connected between attitude control thruster and propellant tank.

Bi-modal propulsion systems and related methods are generally described. In some embodiments, a bi-modal propulsion system may employ a single propellant for both chemical thruster(s), operating at elevated pressures, and electrical thruster(s) (e.g., electro spray thruster), operating at reduced pressures. The propellant pressure may be reduced to a desired operational range of the electrical thruster(s) using any appropriate construction including, for example, capillaries configured to reduce the pressure of the propellant to an operational range of the electrical thruster(s). In some embodiments, the reduced pressure of the propellant may be lower than a vapor pressure of at least one volatile component of the propellant, leading to the formation of bubbles within the propellant line. The presence of alternating gas and liquid phases along a flow path between a propellant tank and the electrical thruster(s) may help to electrically insulate the electrical thruster from the rest of the system.

A debris removal satellite includes a capture device, a thruster of a chemical propulsion method, and a propellant tank to store chemical fuel. A solar array wing is operable in an orbit at an orbital altitude higher than a congested orbit region congested with satellites forming a satellite constellation. The debris removal satellite is built in advance for future use as a satellite to be launched, and when a debris intrusion alarm to give a warning about intrusion of debris into the congested orbit region is issued, propellant is loaded into the propellant tank and the debris removal satellite is launched by a rocket built in advance for future use as a launch rocket. The debris removal satellite captures capture-target debris at an orbital altitude higher than the congested orbit region, and operates a propulsion device with the capture-target debris being captured.

A spacecraft for the distribution of electrical energy to client craft at points situated in free space, in orbit and/or on a celestial body includes a main structure equipped with an electric thruster, with a chemical thruster and with a solar generator, a first fuel container for fuel intended for the electric thruster, and a second fuel container for fuel intended for the chemical thruster. The spacecraft is able to be modulated such that the main structure can be coupled/decoupled alternatively to/from the first container or the second container, the first container and the second container are able to be coupled/decoupled to/from one another, and the solar generator can be deployed or retracted.

A self-contained vertical takeoff and landing vehicle (VTOL) with aspect ratio of height to width no greater than 5.3:1 and with both rocket and airbreathing propulsion systems that can selectively operate one at a time or both at the same time and fuel tanks that have internal lattice structures formed of groups of interconnected multiplicities of fuel cells such as gyroids that line and are integrated with a vehicle skin to form a structural skeleton strengthened with said lattice structures that also serve to reduce fuel slosh compared with fuel tanks lacking such lattice structures and provide other benefits such as fuel temperature profile control.

A debris removal satellite includes a capture device, a thruster of a chemical propulsion method, and a propellant tank to store chemical fuel. A solar array wing is operable in an orbit at an orbital altitude higher than a congested orbit region congested with satellites forming a satellite constellation. The debris removal satellite is built in advance for future use as a satellite to be launched, and when a debris intrusion alarm to give a warning about intrusion of debris into the congested orbit region is issued, propellant is loaded into the propellant tank and the debris removal satellite is launched by a rocket built in advance for future use as a launch rocket. The debris removal satellite captures capture-target debris at an orbital altitude higher than the congested orbit region, and operates a propulsion device with the capture-target debris being captured.