A 246-foot tower at Xidian University in Xi’an, China, has become the world’s first ground-based facility to test every function in the space solar power chain — from concentrating sunlight to beaming electricity wirelessly across a distance and catching it at a receiving antenna. The system passed a formal expert review after demonstrating wireless microwave power transmission across 180 feet, and it did so roughly three years ahead of its original schedule.
At a glance
- Space solar power: The tower replicates what a satellite in geosynchronous orbit would do — track the Sun, focus its light, convert it to electricity, transmit it as microwaves, and collect that energy at a separate ground-based rectenna.
- Wireless power transmission: The facility successfully beamed power across 55 meters (180 feet) in its verification test, satisfying a panel of visiting technical experts and earning formal approval to advance its research program.
- Xidian University: Construction began at the Xi’an campus in 2018 C.E. under the direction of researcher Duan Baoyan; the project covers six distinct research challenges, from microwave beam control to smart mechanical structure design.
Why space solar is worth the trouble
Solar panels on Earth face real limits. Clouds, seasons, and the atmosphere all cut into their output. At night, the planet itself gets in the way. Panels in geosynchronous orbit — about 22,500 miles above the surface — face none of those constraints. By some engineering estimates, a solar array in space could generate six to eight times more energy than the same hardware sitting on the ground.
The obstacle has always been getting that energy back down. Geosynchronous orbit is roughly three times the width of the Earth away. Wireless microwave transmission is the leading candidate for bridging that gap, but the physics of beaming power across tens of thousands of miles with useful efficiency has never been solved at full system scale — until now, at least at a test-tower level.
What the tower actually does
The upper section of the 75-meter (246-foot) structure holds an array of dish antennas that act as a surrogate satellite. They concentrate incoming sunlight, convert it to electricity, and send it downward as a microwave beam. A rectenna — a rectifying antenna — on the ground catches that beam and converts it back to usable power.
That complete loop — light in, electricity out, wirelessly transmitted and received — is what makes this facility a genuine world first. Previous research programs have studied individual links in the chain, but no other system has integrated and tested all of them together in a single structure. The Xidian team describes its research scope as covering high-efficiency light concentration, photoelectric conversion, microwave conversion and waveform optimization, beam pointing and control, microwave reception and rectification, and smart mechanical structure design.
The long road ahead
The researchers are careful not to oversell what comes next. Scaling from a 180-foot test distance to a working geosynchronous system 22,500 miles up, they wrote in their press release, will “require successive struggles of several generations.” A ground-based receiving array for an actual space solar satellite would likely need to span several miles to collect a meaningful amount of energy.
That gap between proof-of-concept and commercial deployment is the honest caveat here. For the foreseeable future, building more solar arrays on Earth will almost certainly deliver more clean energy per dollar spent than any space-based system could. The Xidian tower is a research milestone, not a power plant.
Still, the underlying technology has uses closer to home. New Zealand’s Emrod, for example, is developing wireless microwave power transmission for terrestrial applications — replacing high-voltage lines across difficult terrain where grid infrastructure is expensive or impossible to build. Meanwhile, the European Space Agency’s SOLARIS initiative and the U.K.’s national space solar study are advancing parallel research tracks, reflecting a growing global bet that the physics problems, while hard, are worth chasing.
Launch costs and the bigger picture
One factor that once made space solar purely theoretical is now shifting. The rise of reusable rockets has pushed launch costs down sharply over the past decade, making the economics of orbiting large power infrastructure at least conceivable within this century. The International Energy Agency’s World Energy Outlook projects surging global electricity demand through 2050 C.E., driven by electrification and AI infrastructure — a context that keeps high-yield power research alive even when timelines stretch across generations.
Space launch costs still need to fall much further before a commercial space solar system is viable. But the Xidian tower represents something valuable even in the interim: a permanent, publicly approved research platform where the full system can be studied, iterated, and improved. The fact that it arrived three years ahead of schedule suggests the engineering is moving faster than the timeline projected.
Xi’an — a city most familiar to outside audiences as home to the UNESCO-listed Terracotta Army — now also houses the most advanced space solar test facility on Earth.
Read more
For more on this story, see: New Atlas — China builds world-first full-function space solar verification tower
For more from Good News for Humankind, see:
- Renewables now make up at least 49% of global power capacity
- U.K. cancer death rates down to their lowest level on record
- The Good News for Humankind archive on renewable energy
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