Abstract: A fuel cell-based power system comprises a fuel cell configured for continuously receiving a first reactant and a second reactant to produce chemical reactions that generate electrical power, water, and heat, a coolant subsystem configured for circulating a primary coolant in association with the fuel cell, thereby absorbing the generated heat, a tank configured for storing a reactant, and a reactant distribution subsystem configured for conveying the reactant from the tank to an independent system, the fuel cell as the first reactant, and the coolant subsystem as a secondary coolant to remove the absorbed heat from the primary coolant and/or a water accumulator. The secondary coolant may be conveyed to a gas thruster as a gas after the absorbed heat has been removed from the secondary coolant. The reactant may boil off of a cryogenic liquid or vapor or gas transformed from a cryogenic liquid via a heater.

Abstract: A fuel cell-based power system comprises a fuel cell configured for continuously receiving a first reactant and a second reactant to produce chemical reactions that generate electrical power, water, and heat, a coolant subsystem configured for circulating a primary coolant in association with the fuel cell, thereby absorbing the generated heat, a tank configured for storing a reactant, and a reactant distribution subsystem configured for conveying the reactant from the tank to an independent system, the fuel cell as the first reactant, and the coolant subsystem as a secondary coolant to remove the absorbed heat from the primary coolant and/or a water accumulator. The secondary coolant may be conveyed to a gas thruster as a gas after the absorbed heat has been removed from the secondary coolant. The reactant may be boil off of a cryogenic liquid or vapor or gas transformed from a cryogenic liquid via a heater.

Abstract: A fuel cell-based power system comprises a fuel cell configured for continuously receiving a first reactant and a second reactant to produce chemical reactions that generate electrical power, water, and heat, a coolant subsystem configured for circulating a primary coolant in association with the fuel cell, thereby absorbing the generated heat, a tank configured for storing a reactant, and a reactant distribution subsystem configured for conveying the reactant from the tank to an independent system, the fuel cell as the first reactant, and the coolant subsystem as a secondary coolant to remove the absorbed heat from the primary coolant and/or a water accumulator. The secondary coolant may be conveyed to a gas thruster as a gas after the absorbed heat has been removed from the secondary coolant. The reactant may boil off of a cryogenic liquid or vapor or gas transformed from a cryogenic liquid via a heater.

Abstract: A fuel cell-based power system comprises a fuel cell configured for continuously receiving a first reactant and a second reactant to produce chemical reactions that generate electrical power, water, and heat, a coolant subsystem configured for circulating a primary coolant in association with the fuel cell, thereby absorbing the generated heat, a tank configured for storing a reactant, and a reactant distribution subsystem configured for conveying the reactant from the tank to an independent system, the fuel cell as the first reactant, and the coolant subsystem as a secondary coolant to remove the absorbed heat from the primary coolant and/or a water accumulator. The secondary coolant may be conveyed to a gas thruster as a gas after the absorbed heat has been removed from the secondary coolant. The reactant may be boil off of a cryogenic liquid or vapor or gas transformed from a cryogenic liquid via a heater.

Abstract: An method of controlling thermal transfer between a first structure and a second structure may include a signal at a thermal switch. In response to receiving the signal at the thermal switch, a rotating plate may be rotated into one or more positions adjacent to a fixed plate to facilitate radiative thermal transfer between the rotating plate and the fixed plate. The rotating plate and the fixed plate may be in thermally conductive contact with respective ones of the first structure and the second structure.

Abstract: An method of controlling thermal transfer between a first structure and a second structure may include a signal at a thermal switch. In response to receiving the signal at the thermal switch, a rotating plate may be rotated into one or more positions adjacent to a fixed plate to facilitate radiative thermal transfer between the rotating plate and the fixed plate. The rotating plate and the fixed plate may be in thermally conductive contact with respective ones of the first structure and the second structure.

Abstract: A method of controlling thermal transfer between a first structure and a second structure includes sending a command signal to a thermal switch and actuating an electric motor in response to receiving the signal. The electric motor may move a first thermally conductive member toward and/or in contact with a second thermally conductive member. The first and second thermally conductive member may be in thermally conductive contact with respective ones of the first and second structure.

Abstract: A propulsion system may be operated by determining pressure in a cryogenic liquid tank storing a fluid and cooling the cryogenic liquid tank in response to determining that the pressure is greater than a predetermined value. The cryogenic liquid tank may be pressurized by admitting a gaseous form of the fluid into the cryogenic liquid tank in response to determining that the pressure in the cryogenic liquid tank is less than a predetermined value.

Abstract: A propulsion system may be operated by determining pressure in a cryogenic liquid tank storing a fluid and cooling the cryogenic liquid tank in response to determining that the pressure is greater than a predetermined value. The cryogenic liquid tank may be pressurized by admitting a gaseous form of the fluid into the cryogenic liquid tank in response to determining that the pressure in the cryogenic liquid tank is less than a predetermined value.

Abstract: An oxygen-hydrogen pressurization system includes a cryogenic oxygen tank, cryogenic hydrogen tank, thermal switch, supercritical oxygen bottle, supercritical hydrogen bottle, and pressure management system and a thermodynamic vent system. The thermal switch permits heat to flow between hot and cool areas within the space vehicle to help facilitate pressure management within the cryogenic liquid oxygen tank and the cryogenic liquid hydrogen tank in conjunction with the higher pressure fluid from the supercritical oxygen tank and the fluid from the supercritical hydrogen tank and the added cooling from the pressure management system.

Abstract: An oxygen-hydrogen pressurization system includes a cryogenic oxygen tank, cryogenic hydrogen tank, thermal switch, supercritical oxygen bottle, supercritical hydrogen bottle, and pressure management system and a thermodynamic vent system. The thermal switch permits heat to flow between hot and cool areas within the space vehicle to help facilitate pressure management within the cryogenic liquid oxygen tank and the cryogenic liquid hydrogen tank in conjunction with the higher pressure fluid from the supercritical oxygen tank and the fluid from the supercritical hydrogen tank and the added cooling from the pressure management system.

Abstract: Methods and apparatuses for causing thermal transfer between two structures on command including responding, by a thermal switch, to a command signal by moving a first set of one or more thermally conductive members into a position adjacent to a second set of one or more thermally conductive members, the first and second one or more thermally conductive members having thermally conductive contacts with the first and second structures, respectively.

Abstract: A combined application paraboloid spacecraft structure that is adapted to serve as a structural element for space transportation vehicles, and in additional applications, as a separated spacecraft. The primary structure of the combined application paraboloid spacecraft structure is shaped as the shell of a paraboloid of revolution which has focusing properties for use in such functions as a solar power concentrator, a surveillance or an astronomical telescope, or a communications antenna when deployed in space. The primary structure of this combined application paraboloid can nest and can also be used to support other single or multiple host spacecraft during launch and orbit to orbit transportation.