For those who are interested [link]http://www.ugcs.caltech.edu/~diedrich/solarsails/[/link]. This is Caltech's Solar Sail website. It has TONS of great data. If you're patient, you can find some really interesting scraps hidden inside the news of NASA's JPL site.
My own take is that NASA won't use them for interstellar missions because they are the slowest known form of space propulsion, lagging far behind even ion drives. Even with massive ground-based lasers to augment the effectiveness, they can't hold up to any other form of propulsion and are not going to be used for anything except perhaps a few satelites as a means of giving them theoretically infinited maneuvering abilities so they can keep themselves in orbit much longer than ones with only chemical burners for maneuvers.
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