Orbit-to-ground Wireless Power Transfer test mission

Since the 1970s the concept of transferring power from orbit for use on Earth has had a great deal of consideration for future energy and environmental sustainability here on Earth. The cost, size and complexity of a production-grade system are extremely large, and have many environmental considerations. There has never been a publicly disclosed orbit-to-ground power transfer test mission. A proposed project provides an opportunity to test the conceptual operation of such a system, albeit at a much lower power level than the `grand' or `real scale' system. During this test, a small Solar Powered (SP) 6-U CubSat will be deployed into Low-Earth Orbit (LEO) (225 or 325 km) to collect and store 1 KW of power from solar energy as the satellite is orbiting. The goal is to transmit 1 KW of wireless power at a microwave frequency of 5.8 or 10 GHz to a ground antenna array system. This paper presents the architecture for the proposed mission and discusses the regulatory, legal, and environmental issues that such a mission poses. Furthermore, the gain of the transmitter is analyzed at 20 and 30 dB as well as the gain of the receiver is analyzed at 30, 40, and 50 dB. A SP 6-U CubeSat will have a Lithium Ion (LIon) battery capable of storing enough energy for 83.33 Whr charge to run the satellites controls, and 1 KW necessary for a 5-minute demonstration and test (in addition to power required for its own operational requirements). Once charged, the satellite will use highly accurate position and attitude knowledge provided by an onboard star-tracker, Global Positioning Satellite (GPS) and inertial measurement unit to determine the proper orientation for the power transfer test. The onboard Attitude Determination and Control (ADCS) will be utilized to achieve and maintain this orientation during the test period. A cold-gas propulsion system will be available to de-spin the reaction wheels to ensure that sufficient ADCS capabilities exist for attitude-stabilization use during the experiment. The size and type of solar collector arrays are investigated, as well as the transmitter in order to obtain the proposed 1 KW as well as the power needed to run the onboard systems. A ground receiver station comprised of rectifying antenna (rectenna) arrays will be utilized to receive the microwave energy and convert into Direct Current (DC) which is used to power lights and a fan for proof of concept. Measurements for the ground antenna system will be made on the amount of output DC power (efficiency) as well as the energy density received throughout the array, and Angle of Arrival (AoA) from the satellite. The considerations posed by FCC regulations, the Outer Space Treaty of 1967 and national space and security policies are also discussed. The potential humanitarian, economic, technological and national security implications of the technology advanced by the project are discussed in detail.