Drexler's master's thesis has more detail: https://dspace.mit.edu/handle/1721.1/16234 and pp 7-9 of http://space.nss.org/media/L5-News-1979-05.pdf summarize. I don't know what's been done more recently about space-built sails (or other uses of big, light mirrors).

Japan has operated a solar sail near the orbit of Venus, several countries and companies are running experiments on using them to make satellites deorbit faster, the Planetary Society is launching Lightsail-2 on the next Falcon Heavy, and the Breakthrough Starshot hopes to make scifi a reality and shine a huge laser on tiny chip-scale spaceships to send them to Alpha Centauri.

The field has been active.

It's great to see progress -- I just meant I'm curious about building the sails in space for higher performance, and haven't heard about anyone else trying to refine those ideas.

IANAL, but I wonder if this invention has any significance to the Planetary Society's plan to launch a solar sail satellite in the near future, the LightSail [1]. If I understand the patent correctly, Google has patented (a) a means to steer a light powered craft, and (b) a means to produce solar sail. I understand the LightSail controls the sails by changing the orientation of the satellite with respect to the sun. I have no info on how the sail itself was fabricated. Do they owe Google some money?

[1] http://www.planetary.org/explore/projects/lightsail-solar-sa...

The patent doesn't belong to Google. This is just Google's patent search site.

It's a very different design because the Planetary Society's is built to be launched from Earth and then unfolded, presumably making it much heavier. If it does use ideas from this patent, it must've expired by now.

This patent is from 1980--I don't think it's Google's.

Patents expire after 26 years. Like sane copyright laws should.