A heat pipe has an evaporator portion, a condenser portion, and at least one flexible portion that is sealingly coupled between the evaporator portion and the condenser portion. The flexible portion has a flexible tube and a flexible separator plate held in place within the flexible tube so as to divide the flexible tube into a gas-phase passage and a liquid-phase artery. The separator plate and flexible tube are configured such that the flexible portion is flexible in a plane that is perpendicular to the separator plate.

A heater apparatus configured to provide heat to at least one component of a spacecraft. The heater apparatus comprises a combustion chamber for a hypergolic propellant, and a heat radiator configured to radiate heat from the combustion chamber towards the at least one component to be heated. A spacecraft comprises at least one component to be heated and a heater apparatus configured to heat the at least one component to be heated. A method for heating at least one component of a spacecraft. The method comprises generating heat in a combustion chamber for a hypergolic propellant, and radiating at least a portion of the heat towards the at least one component.

An electrical power system has a dual battery configuration that enables sufficient power supply for a spacecraft bus and a payload module being carried by the spacecraft. During a sunlight power mode, power is drawn from a solar array of the bus to power a low-discharge payload of the spacecraft and a high-discharge payload of a payload module. During the sunlight power mode, a low rate discharge battery and a high rate discharge battery are charged by a battery charge management unit of the spacecraft bus. During an eclipse power mode, the low rate discharge battery powers the low-discharge payload of the spacecraft and the high rate discharge battery powers the high-discharge payload of the payload module. The high-rate discharge battery may also be used to power the high-rate discharge payload in the sunlight power mode to meet its high current demands to meet a flexible mission operations.

A method to improve thermal performance of vascular composites by using a two-phase working fluid for isothermalization includes the steps of: manufacturing a vascular composite structure optimized for a design point; manufacturing a thermal back end sized for the application; integrating the vascular composite into a fluid loop; and evacuating and filling the fluid loop with working fluid to an amount resulting in two-phase operation at the design point.

Techniques for minimizing diurnal temperature variation of a radiator of a spacecraft are disclosed. In one aspect, a spacecraft includes a body, a radiator panel, and a heat dissipating unit thermally coupled with the radiator panel. The spacecraft is configured to operate in an orbital plane, and 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 a roll axis orthogonal to the pitch axis and the yaw axis. The radiator panel includes a surface area external to a body of the spacecraft, a first portion of the surface area facing a first direction that is substantially parallel to the roll axis, and a second portion of the surface area facing a second direction that has a substantial component parallel to the yaw axis.

Retrofittable satellite systems for an in-orbit host satellite comprising an enhancement module for adding a capability to the in-orbit host satellite, modifying the function of the in-orbit host satellite, and/or extending the function of the in-orbit host satellite. The in-orbit, retrofittable satellite system comprises a transfer vehicle for transferring the enhancement module from a first to a second location and a service vehicle for receiving the enhancement module from the transfer vehicle and installing the enhancement module on the in-orbit host satellite. In-orbit space situational awareness systems, comprising one or more in-orbit host satellites having one or more enhancement modules attached thereto, the enhancement modules comprising sensors such as satellite spatial location/position sensors, range sensors, navigation sensors, and/or proximity sensors for detecting other objects in-orbit, their location, speed, acceleration, orbital trajectory or the like, wherein the enhancement modules communicate to create a mesh network between the satellites.

A panel assembly for use with a spacecraft includes a payload, a radiator panel and a heat pipe. The payload is configured to generate waste heat during operation. The radiator panel is spaced apart from the payload and is configured to dissipate waste heat. The heat pipe is coupled to the payload and the radiator panel. The heat pipe includes a compliant portion to permit the radiator panel to move relative to the payload. Further the heat pipe is configured to transfer waste heat from the payload to the radiator panel.

A satellite includes a satellite housing, a temperature sensitive component carried by the satellite housing, and a thermal radiator carried by the satellite housing. A thermal switch is movable between a coupled state and a decoupled state. In the coupled state, the temperature sensitive component and the thermal radiator are thermally coupled. In the decoupled state, the temperature sensitive component and the thermal radiator are thermally decoupled.

An apparatus includes a structure configured to receive and transport thermal energy. The structure includes one or more materials configured to undergo a solid-solid phase transformation at a specified temperature or in a specified temperature range. The one or more materials form a heat input region configured to receive the thermal energy and a cold sink interface region configured to reject the thermal energy. The structure also includes one or more thermal energy transfer devices embedded in at least part of the one or more materials. The one or more thermal energy transfer devices are configured to transfer the thermal energy throughout the one or more materials and at least partially between the heat input region and the cold sink interface region. The one or more materials are also configured to absorb and store excess thermal energy in response to a temperature excursion associated with a thermal transient event and to release the stored thermal energy after the thermal transient event.

Various aspects as described herein are directed to a radiative cooling device and method for cooling an object. As consistent with one or more embodiments, a radiative cooling device includes a solar spectrum reflecting structure configured and arranged to suppress light modes, and a thermally-emissive structure configured and arranged to facilitate thermally-generated electromagnetic emissions from the object and in mid-infrared (IR) wavelengths.