Articles

The author and/or Dr. Janhunen appear to have a few things wrong on solar sails. In particular,

1) Solar sails are 'propelled' by momentum transfer from photons bouncing off the reflective surfaces of the sail. It has nothing to do with the solar wind (the mechanism driving this electric sail concept).

2) Solar sails are indeed capable of thrust-vectoring, in a matter analogous to the method described for electric sails.

3) It is true that no solar sail has been deployed AND tested in orbit, but significant work has been done by groups in Russia, the U.S., Japan and Germany in ground-based development and deployment testing. In particular, both JAXA and NASA have unfurled sail (or sail-like) structures in orbit.

4) Since solar sails just need sunlight, not the solar wind, they can be tested in Earth orbit (albeit with difficulty). For example, NASA/Marshall has the ongoing CubeSail activity to fly a tiny-but-real solar sail demonstrator in low-Earth orbit from a CubeSat (P-POD) deployer.

That being said, this electric sail is an extremely interesting technology, and I hope to see them succeed in getting sufficient sponsorship to keep working towards flight tests.