Update: Successful launch!
In this season of solar sailing (Japan's IKAROS is still going strong), another ship is about to leave the harbor.
NASA's modest solar sail demonstrator, Nanosail-D, is due to launch tonight on a Minotaur 4 rocket from Alaska. You can watch Spaceflight Now's live feed from the Kodiak Launch Complex. Liftoff is scheduled for 8:24 p.m. Eastern time.
Nanosail-D is just one of more than a dozen experiments and technology demos onboard the Minotaur, and will be NASA's first orbital deployment of a solar sail.
It's more an experiment in packaging than propulsion. The Nanosail engineers want to see if the sail can deploy cleanly from its shoebox-size container. If it does, it won't do much actual sailing; there's still enough atmosphere in its low orbit to exert drag on the thin material.
Read about the project here. This video shows how the sail will unfold: