Forward-looking: Recent tests have proven that beaming solar energy to Earth from low-orbiting satellites is theoretically possible with existing technology. If implemented, the method could resolve several flaws of conventional solar panels, providing a continuous source of renewable energy while occupying minimal space.
Researchers from Japan Space Systems (JSS) recently beamed energy wirelessly from a speeding jet to antennae on the ground. The successful experiment confirms the viability of numerous tools that might eventually transmit solar power from space to Earth.
Low-orbit solar panels that beam energy to the surface have multiple advantages over ground-based solar farms. Without interference from the Earth’s atmosphere, they can collect several times more energy. The arrays would send power to Earth in the form of microwaves, which lose only five percent of their energy when passing through the atmosphere.
Furthermore, maintaining proper orbit enables the transmission of solar energy at night, ensuring an uninterrupted, round-the-clock supply. Scientists theorize that solar energy from space might supplement the energy needed to power various land and air vehicles, further reducing carbon emissions. Ground-based receivers would also cover far smaller areas than typical solar or wind farms.
However, some obstacles remain. Significant amounts of energy are lost during conversion to and from microwave emission. Furthermore, all artificial satellites must deal with micrometeorites and the prospect of creating space debris. Some also theorize that orbital microwave emitters could become weapons of mass destruction.
Early JSS experiments confirmed wireless power transmission at distances ranging from 30 to 100 meters, while the latest test achieved complete success from a fast-moving object at 5km (3.1 miles). The scientists flew a small jet over an antenna array and measured energy reception from multiple angles, demonstrating the capability to quickly and accurately redirect microwave transmissions.
The microwave transmissions utilize quantum interference to bounce waves from multiple sources simultaneously, which cancels out all waves except those moving in a chosen direction. The concept resembles the act of splashing waves at multiple points in a body of water, which creates pockets of intense waves that complement each other and calm areas where waves cancel each other out.
JSS ultimately plans to beam energy from satellites orbiting 36,000km (22,369 miles) above the Earth. Researchers from Caltech completed a similar experiment in 2023. The university’s Microwave Array for Power-transfer Low-orbit Experiment directed enough energy from low-Earth orbit to power two LED lights on the ground. Last year, a California startup proposed selling solar power redirected from space using an array of satellites equipped with mirrors.
