Aren't solar sails just for propelling yourself once you're in space? I can't imagine how you could launch off the surface of a planet with a solar sail.
Yes, and even then they're incredibly low thrust devices. A light sail (whether solar or laser powered) may well be viable for sending a tiny unmanned probe to another star system (see [0]). It's really unlikely that it will ever scale up enough to take an average communication satellite the same distance, much less a manned craft.
