Disclosed are a reflector for a bifacial solar module and a bifacial photovoltaic system including the same, wherein the reflector includes a reflecting panel configured to reflect sunrays toward back surfaces of a first bifacial solar module and a second bifacial solar module which are located higher than the ground, a mobile cart configured to support the reflecting panel and be movable below and between the first bifacial solar module and the second bifacial solar module, and a control portion configured to control a position of the mobile cart to maximize power generation amounts of the first bifacial solar module and the second bifacial solar module.

Solar collectors can provide power for electricity, thermal propulsion, and material processing (e.g., mining asteroids). In one aspect, an apparatus for collecting solar energy and simultaneously protecting against damage from a resulting energy beam includes a solar energy collection system including at least one concentrator and a target configured to use, store, or convert the solar energy, the collection system configured to cause solar energy to focus on the target, at least one sensor configured to detect misalignment of the concentrator by determining that some or all of the collected solar energy is offset from the target, and a safety system configured to redirect the energy or interpose a safety structure for shielding other non-target systems from receiving too much solar energy from the collection system.

Omnivorous solar thermal thrusters and adjustable cooling structures are disclosed. In one aspect, a solar thermal rocket engine includes a solar thermal thruster configured to receive solar energy and one or more propellants, and heat the one or more propellants using the solar energy to generate thrust. The solar thermal thruster is further configured to use a plurality of different propellant types, either singly or in combination simultaneously. The solar thermal thruster is further configured to use the one or more propellants in both liquid and gaseous states. Related structures can include valves and variable-geometry cooling channels in thermal contact with a thruster wall.

A secondary reflector for receiving light from a plurality of primary reflectors that includes a reflecting surface having a length aligned along a first axis (z), where a cross-section of the reflecting surface in a plane perpendicular to the first axis (z) forms a curve comprising a concave section positioned between a first endpoint and a second endpoint, at least a portion of the concave section is accurately approximated by a polynomial equation, an aperture is formed by a straight line connecting the first endpoint to the second endpoint, and the concave section is configured to focus a plurality of beams of light passing through the aperture onto a focal point.

An aspect of the present disclosure is a device that includes a reflecting surface having a length aligned along a first axis (z), where a cross-section of the reflecting surface in a plane perpendicular to the first axis (z) forms a curve comprising a concave section positioned between a first endpoint and a second endpoint, at least a portion of the concave section is accurately approximated by a polynomial equation, an aperture is formed by a straight line connecting the first endpoint to the second endpoint, and the concave section is configured to focus a plurality of beams of light passing through the aperture onto a focal point.

An integrated wind and solar solution is provided, including a solar energy collection assembly (100) and a vertical axis wind turbine (400), combined to provide an integrated power output. In preferred embodiments, the vertical axis wind turbine is positioned above the solar energy collection assembly. Concentrating solar mirror collectors (116) are used to direct sunlight to a heat engine (250), which converts the collected heat energy into rotary motion. Rotary motion from the heat engine and from the vertical axis wind turbine preferably are on the same rotating axis (600), to facilitate load sharing between these two sources. A dual axis azimuth-altitude solar panel alignment tracking system is used in order to boost the energy conversion capability of the solar energy collectors.

Omnivorous solar thermal thrusters and adjustable cooling structures are disclosed. In one aspect, a solar thermal rocket engine includes a solar thermal thruster configured to receive solar energy and one or more propellants, and heat the one or more propellants using the solar energy to generate thrust. The solar thermal thruster is further configured to use a plurality of different propellant types, either singly or in combination simultaneously. The solar thermal thruster is further configured to use the one or more propellants in both liquid and gaseous states. Related structures can include valves and variable-geometry cooling channels in thermal contact with a thruster wall.

Solar collectors can provide power for electricity, thermal propulsion, and material processing (e.g., mining asteroids). In one aspect, a rocket propulsion system is configured to produce thrust for a spacecraft and includes: one or more optical elements configured to receive solar energy. The optical elements include: a first window configured to allow energy to enter the rocket propulsion system and form a concentrated energy beam, and a second window positioned to allow the concentrated energy beam to pass to the heat exchanger. The second window is spaced away from the first window to form a pressurized plenum chamber therebetween. The system further includes: a heat exchanger configured to receive the energy and use it to heat and pressurize a propulsion gas, and a rocket nozzle configured to expel the pressurized propulsion gas.

Solar collectors can provide power for electricity, thermal propulsion, and material processing (e.g., mining asteroids). In one aspect, an apparatus for collecting solar energy and simultaneously protecting against damage from a resulting energy beam includes a solar energy collection system including at least one concentrator and a target configured to use, store, or convert the solar energy, the collection system configured to cause solar energy to focus on the target, at least one sensor configured to detect misalignment of the concentrator by determining that some or all of the collected solar energy is offset from the target, and a safety system configured to redirect the energy or interpose a safety structure for shielding other non-target systems from receiving too much solar energy from the collection system.

A system (100) and method can monitor a reflectance of a mirror target that includes at least one curved mirror (M). The system (100) can take a first irradiance measurement of the sun (S), the first irradiance measurement representing a direct solar irradiance. The system (100) can take a second irradiance measurement that represents an irradiance from a reflection of the sun (S) from the mirror target plus background irradiance from a reflection of the sky from the mirror target. The system (100) can take a third irradiance measurement that represents the background irradiance from the reflection of the sky from the mirror target. The system (100) can determine a reflectance of the mirror target from the first, second, and third irradiance measurements. The system (100) can compare the reflectance to a specified reflectance threshold, and, upon determining that the reflectance of the mirror target is less than the specified reflectance threshold, can generate an alert signal.