A prototype of the Shapeshifter robot being tested at the Jet Propulsion Laboratory. (NASA)
As they conceive a new generation of robotic "rovers," NASA engineers are challenging themselves to think outside the box.
The contraptions they envision bear little resemblance to the car-like, six-wheeled cruisers we've followed during rolling adventures on Mars. Future space exploration robots may resemble "Transformers."
That's because a robot operating semi-autonomously on very alien turf must be able to negotiate a broad range of terrains and environmental conditions, the likes of which may not exist on Earth. So, how to design - and prepare the rover - for situations engineers may not even anticipate?
Concept drawings and working models of this robot resemble farm equipment- some kind of rolling grain harvester or threshing machine.
But it helps to see past Shapeshifter's prototype and imagine how engineers might take apart its components and put them back together in different forms to suit different needs, like Lego toys.
To demonstrate this concept, they built the Shapeshifter mockup from two separate and complementary assemblies: a pair of flight-capable drones housed within their own halves of a pipe-frame cylinder structure.
Combined, the prototype can roll like a barrel to easily traverse stretches of flat or mounded terrain. Separately, one half can ascend skyward on propellers, using the other half as a launch pad.
More advanced visions for the Shapeshifter stick with the paradigm of smaller robots working together - "co-bots" - that form different configurations, but involve greater numbers of base robot units.
These simplified future co-bots may combine into forms that can swim through a sea of liquid, fly together to lift and carry other equipment, such as a larger "mothership" lander, or roll around almost any terrain by reassembling into a sphere.
Bizarre Environments Call For Bizarre Robots
In 2005, NASA's Cassini spacecraft dropped the European "Huygens" probe onto the surface of Saturn's mysterious, cloud-shrouded moon Titan. With a simple plan to descend through the thick nitrogen atmosphere on a parachute and set down on any available surface, hopefully with enough battery power for a few minutes of picture-taking, Huygens offered a brief flash of insight into Titan.
NASA scored with that touchdown. Huygens, and further investigations by Cassini from space, demonstrated that Titan is a world like no other in the solar system, worthy of further exploration. Scientists also learned what a challenging physical environment Titan presents, and recognized the need for a new, super-flexible roving machine.
Unlike Earth's quiescent airless moon, Titan has a thick, dynamic and extremely cold atmosphere. Unlike the dry desert plains and mountains of Mars, Titan has a liquid cycle, similar to Earth's water cycle. Titan's rain, rivers, lakes and seas, however, are freezing cold liquid methane - a material that exists as a gas on Earth.
Titan's landscapes include vast plains of dunes, high and steep-walled mountains peppered with deep alpine lakes, complex networks of river-carved canyons, and several wide seas of liquid methane.
In some respects, Titan's physical environment will make it easier for a co-botic transforming Shapeshifter craft to move about.
Its surface gravity is about one-seventh that of Earth. Titan is also the only moon in the solar system with a thick atmosphere - thicker than Earth's - so engineers don't have to reinvent the helicopter propeller to make their Titanian co-bots fly.
Science Fiction Leading the Way?
"Transformers" isn't the only example of unconventional robot designs in the realm of science fiction that have played with ideas like shapeshifting and flexible configurations.
The robots TARS and CASE in the movie "Interstellar" looked like awkward rectangular blocks of plastic or metal, but their designers gave them the ability to articulate smaller building-block components into different configurations to walk, run, climb, lift, and even pinwheel through a shallow extraterrestrial sea as the situation demanded.
I won't go into the liquid-metal polymorphing robot from "Terminator 2," but who knows? Engineers are giving shape and motion to blobs of "ferrofluid" with magnetic fields, so it's not inconceivable that they may one day deploy a fluid "Explorinator" morphing around the surfaces of distant worlds.
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