The last decade has seen an incredible bloom in small autonomous and remote controlled helicopters, AKA drones. It isn’t far wrong to call them ubiquitous, and probably the characteristic technology of the 2010s. (Sorry Siri.)
It isn’t surprising, then that NASA (the National Aeronautics and Space Admin.) has some ideas about what to do with robot helicopters.
This month it is confirmed that the next planned Mars rover will have a copter aboard . (To date, this appears to be known as “The Mars Helicopter”, but surely it will need to be christened with some catchy moniker. “The Red Planet Baron”? “The Martian Air Patrol”? “The Red Planet Express”?)
This won’t be a garden variety quad copter. Mars in not Earth, and, in particular, Mars “air” is not Earth air. The atmosphere is thin, real thin, which means less lift. On the other hand, gravity is less than on Earth. The design will feature larger rotors spinning much faster than Terra copters.
Operating on Mars will have to be autonomous, and the flying conditions could be really hairy. Martian air is not only thin, it is cold and dusty. And the terrain is unknown. The odds of operating without mishap are small. The first unexpected sand storm, and it may be curtains for the flyer. Mean time to failure may be hours or less.
Limits of power and radios means that the first mission will be short range. Unfortunately, a 2 kilo UAV will probably only do visual inspections of the surface, albeit with an option for tight close ups. Still it will extend the footprint of the rover by quite a bit, and potentially enable atmospheric sampling.
This isn’t the only extraterrestrial copter in the works. If Mars has a cold, thin atmosphere, Saturn’s moon Titan may have methane lakes and weather, and possibly an ocean under the icy surface. Titan also has a cold thick atmosphere, and really low gravity—favorable for helicopters!
Planning for a landing on this intriguing world is looking at a copter, called “Dragonfly” [1, 2]. The Dragonfly design is a bit larger, and is an octocopter. <<link>> (It is noted that it should be able to continue to operate even if one or more rotors break.) Dragonfly is also contemplated to have a nuclear power source—Titan is too far away for solar power to be a useful option.
Titan is a lot farther away than Mars, and communications will be difficult due to radiation and other interference. The Dragonfly will have to be really, really autonomous.
Flying conditions on Titan are unknown, but theoretically could include clouds, rain, snow, storms, who knows. The air is methane and hydrocarbons which could gum up the flyer. Honestly, mean time to failure could be zero—it may not be able to even take off.
Both these copters are significantly different from what you might buy at the hobby store or build in your local makerspace. But prototypes can be flown on Earth, and the autonomous control algorithms are actually not that different from Earth bound UAVs. This is a good thing, because we have to program them here, before we actually send them off.
In fact, I think this is one of the advantages of small helicopters for this use. Flying is flying, once you adjust for pressure, density, etc. It’s probably not as tricky as driving on unknown terrain. We should be able to design autonomous software that works OK on Mars and Titan. (Says Bob, who doesn’t have to actually make it work.)
Finally, I’ll note that a mission to Titan should ideally include an autonomous submarine or better, a tunneling submarine, to explore the lakes and cracks. I’m sure this is under study, but I don’t know that it will be possible on the first landing.
- Evan Ackerman, How to Conquer Titan With a Nuclear Quad Octocopter, in IEEE Spectrum – Automation. 2017. https://spectrum.ieee.org/automaton/robotics/space-robots/how-to-conquer-titan-with-a-quad-octocopter
- Dragonfly. Dragonfly Titan Rotorcraft Lander. 2017, http://dragonfly.jhuapl.edu/.
- Karen Northon, Mars Helicopter to Fly on NASA’s Next Red Planet Rover Mission, in NASA News Releases. 2018. https://www.nasa.gov/press-release/mars-helicopter-to-fly-on-nasa-s-next-red-planet-rover-mission
We must go to Titan! We must go to Europa!
Ice Worlds, Ho!