can we explore space with unmanned drones?

If we want to really explore alien worlds, our drones and probes should lead the way.

Drone patrols are nothing new. By now, they're fairly humdrum stuff come to think of it. But what about a drone patrol on an alien world, one that could potentially last for decades and bring us a constant stream of data on everything we wanted to know about the world in question? Well, that's the basic idea behind the new AVIATR proposal, which sees a small, nimble drone flying across Titan with a pair of nuclear batteries that provide an ongoing boost for its propeller.

Since the moon has just one seventh of the Earth's gravity and provides three times the air density, a seemingly hard to control, somewhat flimsy drone here would become an endurance athlete in the skies of Saturn's largest satellite. Soaring between two and nine miles above the surface, it will be able to study the shores of methane and ethane lakes, explore impact craters, image the polar regions for further study, and monitor the weather in such detail that we could consider making weather forecasts for the alien moon. And since it's airborne, it would do its exploration far faster than any remote controlled rover.

AVIATR isn't the first concept drone for space exploration. In fact it has a predecessor intended to scream over the surface of Mars, the ARES. While the creators of ARES had a very similar idea, their propellant was rocket fuel and as soon as this supply was used up, the drone would've landed to become a stationary laboratory. It seems like a rather short-lived mission because there's only so much rocket fuel one can store in a relatively small drone.

But the nuclear batteries to be employed by AVIATR would work around the issue of storing your propellant and thus limiting your drones' range. If anything, scaling up those batteries and putting them into a larger, more powerful drone headed for Mars may be worth considering, though again, there are limitations in this scenario since a Martian drone would be subject to a third of the Earth's gravity rather than a seventh, and have to navigate through very thin air. A plain propeller may not be up to the job of keeping it aloft, though I can see quadcopter designs having some potential merit. Ideally, it would be great if we could come up with what could be a standardized design for flying through alien atmospheres, sending drones to whatever moon just so happens to interest us enough to be worth a closer look with some high precision instruments.

But why would we want to do that rather than customize each drone for its mission, playing to the strengths of each alien environment? For one, that would allow us to mass produce these drones and send them quickly, shaving off many years of development and testing time, casting a wider exploratory net over the solar system and its most interesting worlds. Yes, maybe each drone is not perfect for its mission, but it could collect data needed to justify further exploitation and make measurements one can't make from orbits or flybys. Why can't we use an advance scout to help us better target extensive scientific missions while collecting data we would not ordinarily have without actually sending some sort of probe? After all, we sent probes to just have a look at different objects of interest all the time.

The second advantage of mass produced extraterrestrial drones is the ability to significantly cut costs for curiosity-driven exploration. Combined with SpaceX's ambitious plans for a fully reusable rocket, we could consider scientific study of solar system objects to consist of picking a target of interest, reaching for the next available rocket, loading it with the next available drone, and launching it with just a few months notice. Even without a reusable rocket, not having to build each drone from scratch should already save hundreds of millions of dollars for a mission. Hey, if we'll have to boldly go on a budget, why not boldly go with an economical fleet of drones built for speed and efficiency?

See: Barnes, J., et al. (2011). AVIATR — Aerial Vehicle for In-situ Airborne Titan Reconnaissance Experimental Astronomy DOI: 10.1007/s10686–011–9275–9