[wyattearp]

There is, however, the minor difficulty of coming back the same way....

THANK YOU! A spacecraft with a solar sail does NOT work like a sailboat at sea. A solar sail equipped spacecraft can go in one direction - away from the sun. It can be redirected only slightly, but will always be moving outbound. You cannot tack into the solar wind and come back towards the sun, because you do not have the resistance of the ocean against the hull like in a sailboat. No rudder, no keelboard, and you are not displacing anything. A solar sail equipped ship goes out, and does not come back.

[r9etb]

To be fair, the guys do mention the need for a "braking unit" on the other end. However, there remains the problem of setting the damned thing up in the first place.... Not the sort of thing you can just land and hope it works.