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An ambitious project is underway: scientists around the world want to install solar panels in space to continuously capture energy and transmit it to Earth via microwaves or lasers, offering a new energy alternative to the planet.
A team of scientists in California is exploring a different way of thinking about clean energy. Their proposal goes beyond the atmosphere. Literally. They want to harness the solar energy in space and bring it more efficiently to Earth.
The idea is not new. It has been appearing in science fiction books since the 1940s. But now, researchers are putting the concept to the test with real-world tests, albeit on a small scale.
The challenge of bringing energy from space
Capture solar energy in space has one advantage: the supply would be constant. Unlike terrestrial solar panels, which depend on the weather, in space the sun shines all the time. This is increasingly attracting the interest of experts in the energy.
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But transmitting this energy from space to Earth is not so simple. The energy beam, usually in the form of microwaves, needs to be very well directed.
And because the distance is so great, the energy tends to disperse. This requires giant transmitters in space and large receivers on the ground, which is expensive and complex.
The idea of spatial relays
That's where the proposal by Ali Hajimiri, a professor at the California Institute of Technology, and his team comes in. They're thinking of placing intermediate transmitters orbiting the Earth.
As if they were relays space (electromechanical or electronic devices used to control electrical circuits), they would help redirect energy from space to receivers on the ground more accurately.
According to Hajimiri, this relay system allows the use of smaller transmitters and receivers. “Programmable transmission arrays placed in some intermediate orbit could greatly alleviate this size requirement.”, says the researcher.
how the system works
The proposed model involves a constellation of antennas. These sets of transmitters take turns capturing and redirecting energy.
When one group is moving away from the transmission sweet spot, another group approaches and takes over the job.
These orbital relays sit between the main space solar array — the so-called active array — and receivers on Earth. They allow the energy beam to be adjusted along the way, increasing the chance that more energy will reach its destination.
Promising test results
To test the concept, the researchers created simple, inexpensive prototypes. In one experiment, they placed a transmitter and receiver 3,8 feet apart inside an anechoic chamber, which simulates the space environment by preventing wave reflections.
With the relays, they were able to transfer almost 2,5 times more energy than the direct method. This shows that the system could work better over longer distances, or allow the use of smaller equipment.
Even though it was a small-scale test, the results excited the team. They believe the system could be a good solution to current space energy challenges.
Next steps and vision for the future
Much remains to be done. A complete system for transmitting energy from space to Earth is still far from becoming a reality. But Hajimiri and his colleagues are already planning future tests. The goal now is to develop large-scale transmission arrays and test how they behave in a space environment.
The professor also acknowledges that adding these relays to the system would increase initial costs. However, he believes that the efficiency gains would pay off over time. The system would become more economical per unit of energy generated.
As the world searches for cleaner, more reliable ways to produce energy, ideas like this show that thinking outside the box can be part of the solution.
