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.
Perching Ambush Drones
'On the chest of drawers something was perched.' - Philip K. Dick, 1956.
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.
Tactile Skin Supplier Map
'What strange sensitivity! What an amazing development of science was manifested in every move and act and word of this Robot!'
Orb Nomad Zero-Emission Electric Aircraft
'That explains how it was so easy for me to remain motionless in midair or to perch on a flagpole in imitation of a giant bird, even in the windy city of Chicago.'
DIY Robot Scorpion Crushes It
'...it raised its front end off the ground and waved its antennae at them, then raised one armoured claw as if to snip them out of the sky.'