Sandia National Labs and Northrup Grumman have been working on nuclear drones that could stay up for months at a time. NASA has even been given a proposal for a nuclear powered drone mission to Titan.
(Dragonfly nuclear drone mission to Titan)
The idea is that a nuclear-powered drone could not only stay up for a very long time, but could carry more payload, varied weapons and stay on station for longer.
As I recall, the eyes, world-spanning drones from Roger Zelazny's 1966 story This Moment of Storm must have used some sort of very long lasting power source, since they stayed up almost indefinitely. Just the thing for one person to use to monitor an entire planet.
Small Town Wants 60 License Plate Readers
'the registration number which the traffic control automatically photographed as she left the controlway...' - Robert Heinlein, 1940.
Technovelgy (that's tech-novel-gee!)
is devoted to the creative science inventions and ideas of sf authors. Look for
the Invention Category that interests
you, the Glossary, the Invention
Timeline, or see what's New.
Orion's 'Skip-to-M'Lou' Entry
'A lightning pilot possibly could land that tin toy without power and still walk away from it provided he had the skill to play Skip-to-M’Lou in and out of the atmosphere...'