Antenna Arrangement Verification for Low Sidelobe Levels

Space-to-earth Wireless Power Transfer (WPT) in large scale will not be allowed unless the side lobe levels (SLL) can be reduced many orders of magnitude lower than the current technology allows. In particular, high SLL could potentially interfere with aircraft communications around the beam, while the area inside the beam would necessarily be a no-fly zone, similar as over nuclear power plants. To overcome this, the transmitting antenna must be cleverly designed and controlled. In this work, independent validation of the layout, spacing, and envelope arrangement of a design first proposed in 2016 is performed and presented. This design involves a hexagonal design with a triangular antenna element arrangement and a spacing of 0.8 wavelengths using the Dolph-Chebychev beam profile. While this has been shown to produce -240 dB SLL in the AWR Design Environment already, it will now be analyzed using the MATLAB Phased Array System Toolbox. The design will also be investigated on a smaller scale, with the potential for use in other applications, including the powering of low orbit weather balloons or unmanned aerial vehicles (UAVs). The possibility of very low SLL would be transformational in these and other WPT applications, including space solar power, and could greatly benefit humanity and the environment

Wireless Power Transfer to Sitallite Stratospheric Platform

The following topics are dealt with: artificial satellites; ionospheric electromagnetic wave propagation; Global Positioning System; satellite navigation; ionospheric techniques; radiowave propagation; space vehicle electronics; ionospheric disturbances; total electron content (atmosphere); and magnetic storms

Space Nuclear Power for Terrestrial Utilities

Solar power satellites must be large because sunlight is diffuse. Recent advances in developing fission fuel on the Moon raise the possibility of a nuclear powersat. Modest payloads of uranium oxide, transmuted from lunar thorium, and delivered to GEO are inserted into fission reactors. Eighty such reactors attached to a spacetenna can provide GW-class baseload power to terrestrial utilities. This paper studies the size, logistics, and safety considerations for Space Nuclear Power. A particular technical concern is the thermal management required of a heat engine. The delivery of fuel pins from the Moon is studied, and various transport methods are compared. The transfer of power wirelessly is studied, as it impacts terrestrial communications. Of prime concern to all are the safety considerations, which are partly ameliorated by the use of U-233 as the fissile material. A Risk Analysis is presented, and the highest ranking solutions presented. Life Cycle Analysis considerations demand a practical end-of-life treatment. The design of the nuclear powersat aims to strictly minimize any use as a weapon, with the goal being no greater threat to earth than an inert body of similar mass. Through lunar resource utilization, the time may be advanced when utilities can provide baseload (always on) electric power, which is free of pollution

Performance Estimates for a Fuel-Free Stationary Platform in the Stratosphere

High-altitude pseudo-satellites (HAPS) may be kept aloft indefinitely with station-keeping provided by plasma air thrusters (PAT) using wireless power transfer (WPT) from a terrestrial phased array antenna (PAA). One example is the patented “Sitallite” superpressure balloon with a rectifying antenna (rectenna) covering its underside, with thrusters around the periphery. Such a stationary platform can provide continuous observation and communications capabilities covering vast areas for a fraction of the cost required for an orbiting satellite. This work builds upon the design and safety study published elsewhere to provide performance estimates for a long-duration, persistent HAPS powered by electronically-steerable microwave beams. Newly-derived efficiency equations are used to provide accurate estimates of free-space WPT transfer efficiency based on the dimensions of the ground-based PAA and the rectenna. Calculations of air drag for a spheroidal bouyant shape are used to derive PAT power requirements, and these, together with power conversion circuitry, are used to size the overall system. Accurate estimates of cost are derived. These performance estimates can be used to help make economic and logistic decisions, as a fuel-free HAPS with PAT and powered by WPT can be lofted in less time, and with lower risk, than an orbital satellite of comparable capabilities