Drones and helicopters flying on the red planet might glow as they fly by, creating tiny electric currents in the Martian atmosphere.

That's according to NASA scientists who say the physics involved aren't actually alien; it's similar to the phenomenon on Earth known as St. Elmo's Fire that's sometimes seen around ships and planes in electrical storms.

"The faint glow would be most visible during evening hours when the background sky is darker," William Farrell, of NASA's Goddard Space Flight Center, said in a statement.

Farrell is the lead author of a study published last year in the Planetary Science Journal. It describes his team's use of lab measurements and computer models to investigate how the rotor blades of a drone or helicopter might build up an electrical charge in a dusty environment like that on Mars. 

"The electric currents generated by the fast-rotating blades on drones are too small to be a threat to the craft or the Martian environment, but they offer an opportunity to do some additional science to improve our understanding of an accumulation of electric charge called 'triboelectric charging,'" Farrell wrote.  

The atmosphere of Mars is remarkably thin and the resulting low pressure makes for more ideal conditions for this accumulation to occur. The team hypothesizes that the currents generated by flying a drone on Mars would be small but possibly energetic enough to create a blue-purple glow around such a small craft in flight. 

NASA already has a small helicopter named Ingenuity that's been making experimental flights from the surface of Mars for the past year, but it's not able to fly at the right dusky hour. 

"Future drones could be cleared for evening flight and look for this glow," Farrell writes. "In fact, one could even place small electrometers up near the blade and at the legs to monitor the effects of any charging. This kind of electrical monitor could be of both scientific value and provide critical input on drone health during the flight."

Humanity's interminable wait for Martian glow-in-the-dark drones may finally be over soon.