Among all the challenges of sending robotic explorers to other planets and moons, nailing the landing has to be the most nail-biting part. Now, a team at NASA's Ames Research Center in Mountain View has devised a strange, flexible "super ball bot" concept that could take a rough landing on another world's surface and use the same structure to start rolling like a tumbleweed around the terrain.
The super ball bot is unlike any landing gear ever sent to another planet. For example, the 2004 Mars rovers Spirit and Opportunity essentially used a giant airbag ball to cushion the spacecraft as it bounced across the surface. It looks safe – until you consider that one sharp rock at just the right angle could puncture the thing as it bounced. The new-and-improved 2012 rover Curiosity used a highly complex landing system, including a supersonic parachute and a hovering platform, to lower the rover to the surface -- a series of events that became part of the dramatic "seven minutes of terror."
But this system would be completely different, Vytas Sunspiral, a senior robotics researcher at NASA Ames, explains in a NASA video. It sports a semi-rigid but flexible structure, made of stiff poles and stretchy cables, that can distribute the force from an impact at one point all over its system, protecting the payload of scientific instruments suspended at its center.
He added that it's a lot like a much more familiar shock-absorption system: our own skeletons.
"We have traditionally built robots in this very rigidly connected manner where you have elements that are hinged together with motors, but that's not how we work," Sunspiral said. "There's no pin that holds our bones together. There's no rigid hinge there. In fact there's a lot of fluidity and a lot of freedom of motion between the bones."
And, unlike the airbag or hovering aircraft systems, the super ball bot landing structure is also a roving system. Using the same globular network of poles and cables, the robot can get rolling and pick its way across the surface. The bots will also need smart software that will allow them to "evolve," picking the right rules to guide them across unfamiliar terrain, all without constant direction from a human handler on Earth. The researchers are working on prototypes.
"The point of this is to create a landing system that can both act like an airbag ... and then once it's landed, that very same structure can roll and move," Sunspiral said.
With no need to pack extra landing equipment, this could save money and energy, as it would require less fuel to send the rocket carrying it into space. This could make for much cheaper missions down the line, the researcher said.
But because the robots are so space-efficient -- they could fold up during flight, taking up much less room -- it could also mean that scientists could send not just one, but dozens of them to a new world to study.
One ideal place to send a team of rolling robots? Saturn's icy moon Titan, NASA says.
"Such teams will allow rapid, reliable in-situ exploration of hazardous destinations such as Titan," according to a NASA page explaining the robot concept, "where imprecise terrain knowledge and unstable precipitation cycles make single-robot exploration problematic."