Abstract: Technology is disclosed herein for orbit raising of multiple spacecraft launched with a single launch vehicle. Two or more spacecraft are configured in a stacked launch configuration in which a lower spacecraft is mechanically coupled with a payload adapter of a launch vehicle with one or more upper spacecraft above the lower spacecraft. Propellant that is stored in the lower spacecraft during launch is transferred to an upper spacecraft in the stack after launch. The propellent may be used by the upper spacecraft for an orbit raising maneuver that raises the orbit of at least the upper spacecraft from a first orbit to a second orbit. Storing the propellant in the lower spacecraft lowers the center of mass of the stack during launch. Lowering the center of mass reduces the structural bending moment of the stack during launch, which allows a greater total launch mass.

Abstract: Technology is disclosed herein for using an antenna reflector to regulate a spacecraft temperature during orbit raising. When in a launch configuration, the antenna reflector may be stowed in a fairing of a launch vehicle. After the spacecraft is deployed from the launch vehicle and prior to orbit raising, the antenna reflector is moved from the launch configuration to an orbit raising configuration in which the antenna reflector is used to regulate the spacecraft temperature. The antenna reflector may be proximate a thermal radiator panel of the spacecraft when in the launch configuration. The antenna reflector may be positioned such that sunlight will reflect off the antenna reflector onto the thermal radiator panel, thereby warming the spacecraft. After orbit raising, the antenna reflector is moved from the orbit raising configuration to an operational configuration in which a boresight of the antenna reflector may be directed toward nadir.

Abstract: A spacecraft includes a semi-rigid solar array and a main body structure, the main body structure configured as a convex polyhedron and including an aft and a forward face disposed opposite to the aft face and at least four side faces disposed between and approximately orthogonal to the aft face and the forward face. The solar array includes a number of panels linked together with flexible couplings. In an undeployed configuration, panels of the solar array cover at least two adjacent side faces, the flexible couplings providing an articulable joint approximately aligned with a line along which the two adjacent side faces are joined and connecting a first panel of the solar array and a second panel of the solar array, the first panel being proximal to a first side face and the second panel being proximal to a second side face.

Abstract: A cooling system for power electronics, the system comprising: a cooling module having inlet and outlet ends, an inlet side with an inlet channel for receiving, at the inlet end, a flow of cooling fluid and an outlet side having an outlet channel through which, at the outlet end, outlet flow exits the system, the inlet and outlet channels being on a first face of the cooling module; and a cooling plate mounted on the other face of the cooling module and forming with the cooling module a cooling chamber in fluid communication with the inlet and outlet flow channels via a plurality of cooling fluid passages located on opposite sides of the cooling module, such that, in use, flow of cooling fluid in the cooling chamber is from the inlet side to the outlet side.

Abstract: A spacecraft includes a propulsion system including an inert gas stored in a set of pressurant tanks, one or more electric thrusters operable with the inert gas, one or more cold gas thrusters operable with the inert gas; and a pneumatic arrangement including commandable valves.

Abstract: A spacecraft includes a propulsion system that includes one or more pressurant tanks configured to store an inert gas at a high pressure, one or more propellant tanks configured to store liquid propellant at an intermediate pressure, electric thrusters operable with the inert gas at a low pressure and pneumatically coupled with the one or more pressurant tanks by way of a first pressure regulator, and chemical thrusters operable with the liquid propellant. The inert gas is one or a mixture of two or more of xenon, argon and krypton. At least a portion of the liquid propellant is stored in at least one of the propellant tanks, the propellant tank including an ullage volume pneumatically coupled with at least one of the pressurant tanks by way of a second pressure regulator having an output set to the intermediate pressure and the ullage volume is pressurized by the inert gas.

Abstract: A first spacecraft includes a first fluid storage arrangement and a fluid flow metering arrangement including a holding tank coupled with the first fluid storage arrangement, a flow meter disposed proximate to the holding tank, and an active thermal control arrangement controlling the temperature of the flow meter and the holding tank. The first spacecraft is configured to service a second spacecraft, the second spacecraft including a second fluid storage arrangement, by transferring one or both of a propellant and a pressurant from the first fluid storage arrangement to the holding tank, and from the holding tank, through the flow meter, to the second fluid storage arrangement.

Abstract: A spacecraft includes a structural interface adapter for mating to a launch vehicle, an aft surface disposed proximate thereto, and a forward surface disposed opposite thereto, a main body structure, including a plurality of sidewalls, disposed between the aft surface and the forward surface and a plurality of unfurlable antenna reflectors. At least one unfurlable antenna reflector is configured to be illuminated, in an on-orbit configuration, by a respective feed array. The spacecraft is reconfigurable from a launch configuration to the on-orbit configuration. In the launch configuration, the at least one unfurlable antenna reflector is disposed, undeployed, forward of the respective feed array, proximate to and outboard of one of the plurality of sidewalls. In the on-orbit configuration, the forward surface is substantially earth-facing and the at least one unfurlable antenna reflector is disposed, deployed, so as to be earth-facing from a position aft of the respective feed array.

Abstract: Techniques for articulating a sunshield to shade portions of a spacecraft are disclosed. In one aspect, a spacecraft includes a body and an articulable sunshield. The spacecraft is configured to operate in an orbital plane, such that the spacecraft has a yaw axis within the orbital plane and directed from a spacecraft coordinate system origin toward nadir, a pitch axis orthogonal to the orbital plane and passing through the spacecraft coordinate system origin, and a roll axis orthogonal to the pitch axis and the yaw axis and passing through the spacecraft coordinate system origin. The sunshield is configured to rotate about an axis substantially parallel to the pitch axis such that a selected location of an exterior portion of the body is shaded from the Sun by a surface of the sunshield irrespective of seasonal and diurnal variations in orientation of the spacecraft with respect to the Sun.

Abstract: A spacecraft includes a structural interface adapter for mating to a launch vehicle, an aft surface disposed proximate thereto, and a forward surface disposed opposite thereto, a main body structure, including a plurality of sidewalls, disposed between the aft surface and the forward surface and a plurality of unfurlable antenna reflectors. At least one unfurlable antenna reflector is configured to be illuminated, in an on-orbit configuration, by a respective feed array. The spacecraft is reconfigurable from a launch configuration to the on-orbit configuration. In the launch configuration, the at least one unfurlable antenna reflector is disposed, undeployed, forward of the respective feed array, proximate to and outboard of one of the plurality of sidewalls. In the on-orbit configuration, the forward surface is substantially earth-facing and the at least one unfurlable antenna reflector is disposed, deployed, so as to be earth-facing from a position aft of the respective feed array.

Abstract: An electric coolant heater assembly (10) has a coolant gallery (12) connected at each end to a fluid line of an engine's (E) coolant system (C). The gallery defines a fluid flow path through the assembly and includes baffles (24) for inducing turbulent flow to the fluid. A housing (20) mounted on one side of the gallery includes drive control electronics (18) for the assembly and a heater unit (14) is installed on the opposite side of the gallery. Heating elements (26) comprising the heater unit are energized by the drive control electronics. The drive control electronics are responsive to inputs from an external engine controller to operate an electric pump (P) and activate the heating elements so, at initial engine start-up, cause the coolant temperature to rise more rapidly than it otherwise would and assist the engine in reaching its nominal operating temperature faster than it otherwise would.