Nasa engineers are developing a Martian quadcopter designed to fly in the Red Planet’s thin atmosphere and gather samples from sites inaccessible to rovers.
The Martian drone, under development under the Extreme Access Flyers programme, would use a lander as a base to refuel and re-charge its batteries between missions.
In addition to Mars, it could work on asteroids and the Moon or other celestial bodies lacking atmosphere.
"This is a prospecting robot," said Rob Mueller, senior technologist at Nasa's Kennedy Space Center in Florida. "The first step in being able to use resources on Mars or an asteroid is to find out where the resources are. They are most likely in hard-to-access areas where there is permanent shadow.”
While a crater with steep walls may be too much for a Curiosity-style rover to tackle, a flying drone would be able to easily descend to its bottom and return back with whatever it finds there.
The engineers envision the drones would be fuelled by propellants made of locally available resources and would be delivered to the target planet or asteroid aboard a lander. Ideally, multiple drones would be delivered at the same time, so that they could be easily replaced if any single one broke down.
Unlike Earth-bound quadcopters, the Martian one would not use rotors to keep itself in the air but cold-gas jets using oxygen or steam water vapour. Moreover, it would require an autonomous navigation system, as there are no GPS signals available on Mars.
The Nasa team has so far experimented with a program that would enable the drone to recognise landmarks in the terrain and guide itself to areas based on ground controllers’ commands.
For the sampling itself, designers currently envision a modular approach that would let the flyer take one tool at a time to a sample area to gather approximately seven grams of material at a time. This is sufficient for instruments to analyse. With multiple flights, the Earth-bound scientists would be able to get a complete picture of the geology of the area.
Many of the technologies used in the project are based on existing systems for unmanned aerial vehicles.
"The flight control systems of commercially available, small, unmanned multi-rotor aerial vehicles are not too dissimilar to a spacecraft controller," Mike DuPuis, co-investigator of the Extreme Access Flyer project. "That was the starting point for developing a controller."
The team is currently testing prototypes of several sizes and shapes to refine the design of the final vehicle.
The space exploration drones, the researchers believe, could also find use in terrestrial conditions - for example, in areas contaminated with toxins or radiation.