It's still a fascinating idea, doing something with the solar power up there.
And I enjoyed reading 3 long articles on related subjects. First I tried to find an original Chinese news article on the matter. Found one, google translated it - and it doesn't mention the specific 500km altitude. Maybe that number related only to a singular test.
Anyway. This article here was a great about a Russian guy pushing for illuminating 10-70 km2 areas from space, the "Banner" project mentioned in the ABC-story. The space test (and his team's) was successful in beaming light from a structure jettisoned from the MIR - but the receiving regions on earth were mostly under cloud cover (!) so didn't "see" much. A really great read for your morning cuppa.
https://motherboard.vice.com/en_us/a...night-into-day
A retired professor, Susumi Sasaki, explains the project of Japan's
Space Solar Power System, SSPS, his country's rather solitary approach to collect solar power in space and beam it down via laser or microwave (better bc mw aren't scattered by clouds like laser is) to a receiving station on earth. By 2030, he projects, construction of the 1st 1GW SSPS-station could begin - if an international cooperation finds the funds for it for Japan can not finance it alone.
The on-earth test in late 2014 Sasaki mentions has been successful. But I couldn't find anything on the low-orbit test in 2018. These
FAQ give an overview on the required research areas and obstacles. The page appears to have been last updated in 2013. So not sure how much progress has been made since the 2014 Sasaki editorial on IEEE.
Another nice-to-read-article, just not at all technical, is the
Guardian one from 2013 about a small town in Norway near Oslo, Rjukan, which sits in a trough surrounded by high mountains and doesn't get direct sunlight for 6 months a year. Until an artist pursued and realized deflecting sunlight from mountain based mirrors down into the market square. Where town people can sit on new benches and get their winter blues lifted.
