I still think there's lots of benefits to be had (and lots of money to be made) from replacing many of current satellites with high-altitude solar-powered UAVs. They'll be much cheaper to design and manufacture (no need for satellite-grade sterility, or engineering for microgravity environment), much easier to service and replace, and they'd offer some capabilities impossible for satellites (like not flying around the globe).

I've said that before, and got plenty of skeptical looks. I recently learned, however, that I'm not the only one thinking this - in fact the concept has been dubbed "atmosats", "pseudosats", or "HAPS". ESA seems to be into it now:

http://www.esa.int/Our_Activities/Navigation/Crossing_drones...