When I say enormous, I mean enormous. We're talking 500-ft wingspan here. The idea is it would be a permanent sub-orbital (60,000-90,000ft) base, powered by the sun and capable of carrying 1,000lb of gear. It could cruise around, taking high-res photos for map applications or meteorologists, or maybe a few of them could carry transceivers for bouncing signals around. Or, considering it's DARPA doing this, it might carry a couple precision-strike missiles or bunker busters.
In any case, they've checked out a few designs and the one they contracted for (from Aurora Flight Sciences) has unfortunately not been photographed. It's got a 493-ft wingspan in a tri-section design with hinges that allows it to rotate and get the best possible exposure from the sun. Aerovironment tried something like this called the Helios (pictured above) but the conditions took their toll and it, well, crashed. Here's hoping Aurora and their "Odysseus" craft fare better.
[via The Register]