I guess their model starts with "assume a spherical person"...

I haven't posted on /. for years (though I've been reading it...), but I simply wanted to share this. I was recently at a conference (attending mostly by academics who have been funded/supported by Germany) where Schavan gave a speech. It was utterly horrible: pompous, pretentious and condescending, half the sentences were grammatically correct but devoid of information, the other half contained mostly bullshit, wild hyperbole designed to sound grand, and misinformation. I was literally writhing in my seat in agony. The speech was surely impossible to satirize. Even the late, great Loriot (http://en.wikipedia.org/wiki/Vicco_von_B%C3%BClow) couldn't beat this speech. Anyway, now it looks like she, too, may have plagiarized her PhD. Call me vindictive, but I really hope this pans out...

This means that Holger Müller is the guy who logged onto arXiv and uploaded the paper. It has nothing to do with who actually contributed how much to the research.

I can imagine that shopkeepers might oppose parks on the grounds that urbanly stressed people are more likely to buy stuff they don't need.

I think the term "solar sail" is a bit of a misnomer here. If I understood correctly, almost all the thrust comes from the recoil of particles boiling off the surface, because the surface is heated by a microwave beam. This thrust is therefore perpendicular to the surface of the "sail", which is (largely) independent of the direction towards the microwave source. The exception is that, if the sail is parallel to the beam, then the microwaves don't hit the sail at all, and the system doesn't work.

But it would work perfectly well for travelling towards the microwave source (i.e. Earth), or, equivalently, for slowing down on the way to Mars: just have the paint on the other side of the sail, which gets heated from behind.

So one can imagine a craft which has two sails. The first is unfurled in Earth's orbit, with paint facing the Earth, which is used to kick it in a suitable direction to get it to Mars. After the microwave beam is turned off, the sail is discarded. Once the craft gets close to Mars, it unfurls a second sail, this time with paint on the other side, pointing towards Mars. Again a (extremely well focussed!) microwave beam from the Earth heats this sail from behind and the craft can slow down to safe speeds to land on Mars.

Of course, if your beam is so well focussed that you can use the sail near Mars, then you can use a much weaker beam for much longer to get up to the same (or greater) speed. This means you don't need a 60 megawatt beam at all - just use a 1 megawatt beam for 60 hours or whatever.