The ability to beam power from space to earth has long been a staple of Science Fiction books and movies. On the surface it makes sense, space is huge and if we can setup solar panels in space to collect energy and get it to earth in a usable format then it is a win-win. No more having to deal with fossil fuels/nuclear reactors etc. Folks have been working on this for over 5 decades now and progress was slow as most people focused their efforts on other options such as improving land based solar panels, geothermal etc etc.
Now researchers from California Institute of Technology (Caltech) have successfully demonstrated MAPLE (Microwave Array for Power-transfer Low-orbit Experiment) which is an array of 32 flat antennas packed onto a surface slightly larger than a dinner plate. During the experiment the energy was transmitted to earth and successfully received by a receiver on the roof of the Gordon and Betty Moore Laboratory of Engineering and they were able to successfully target receivers about a foot away alternatively and transmit ~200 milliwatts of power to the receiver that powered a LED light.
Using constructive and destructive interference between individual transmitters, a bank of power transmitters is able to shift the focus and direction of the energy it beams out—without any moving parts. The transmitter array uses precise timing-control elements to dynamically focus the power selectively on the desired location using the coherent addition of electromagnetic waves. This enables the majority of the energy to be transmitted to the desired location and nowhere else.
MAPLE features two separate receiver arrays located about a foot away from the transmitter to receive the energy, convert it to direct current (DC) electricity, and use it to light up a pair of LEDs to demonstrate the full sequence of wireless energy transmission at a distance in space. MAPLE tested this in space by lighting up each LED individually and shifting back and forth between them. The experiment is not sealed, so it is subject to the harsh environment of space, including the wide temperature swings and solar radiation that will be faced one day by large-scale SSPP units.
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MAPLE also includes a small window through which the array can beam the energy. This transmitted energy was detected by a receiver on the roof of the Gordon and Betty Moore Laboratory of Engineering on Caltech’s campus in Pasadena. The received signal appeared at the expected time and frequency, and had the right frequency shift as predicted based on its travel from orbit.
This is a big step forward, but I still have major doubts about the feasibility of the project, at least in the current form. Here we are using microwaves to transmit the energy from space to earth, at the level of power we need to transmit the microwave beam will cook anything that crosses it, for example if a plane flies through the beam you can say goodbye to the passengers. Even if we decide that we will establish a no-fly zone around the area what is to stop birds etc from flying into the beam and getting fried. Another problem is that microwave beams generate heat as a side-effect and that can cause a major heating of the atmosphere and change the air-currents which can cause a massive environmental impact.
We also need to consider that in order to collect the solar energy at a scale where it would be useful and make financial sense we would need to setup massive solar-panels in space. This will case a huge problem for astronomers. We already have issues being caused by the Starlink Satellites, this will be the same but at a much larger scale.
However, that being said I see the potential and if we can ever get quantum entanglement or spooky action at a distance as Einstein called it working reliably and consistently then that could potentially be used to transmit the power to earth without frying everyone in the path.
Lets see what else the researchers come up with…
Source: Caltech.edu: In a First, Caltech’s Space Solar Power Demonstrator Wirelessly Transmits Power in Space
Science.org: Satellite beams solar power down to Earth, in first-of-a-kind demonstration
– Suramya
