It will be years before Amazon's dream of same day package deliveries via drone will ever become a reality. But you can forget about trying to shoot one down for some free electronics thanks to new software that allows a quadcopter to stay aloft—and on course—even after losing one or more of its propellers.

As demonstrated in this video created by researchers at ETH Zurich, normally when a quadcopter loses one of its propellers it's game over. The software on board that keeps the craft stable doesn't have a clue how to compensate, and down it goes. But thanks to advanced flight algorithms the researchers have developed, this drone not only stays aloft after one of its propellers flies off, it also returns to the last spot where it was hovering.

And remarkably, the researchers claim this intelligent flight control system—which can be added to any quadcopter via a simple software upgrade—works even if it loses two or three propellers. Of course, a quadcopter probably wouldn't have enough lift to stay airborne if that happened, but with this improved software it could help reduce the impact of an unplanned landing, or steer the quadcopter to a safe place to crash. [YouTube via IEEE Spectrum via Robohub]