London, May 31 : Engineers have designed inflatable, spherical, and lightweight robots, which one day might economically explore vast regions of Mars and other robots.
According to a report in New Scientist, while researchers have proposed rolling spherical rovers before, no one has previously suggested making them inflatable.
With funding from the Swedish National Space Board, Fredrik Bruhn and his team from Angstrom Aerospace in Uppsala, Sweden, has designed an inflatable version with a diameter of just 30 centimeters when it gets pumped full of xenon gas from an internal cartridge on landing.
Crucially, when deflated and stowed, the inflatable occupies just half the volume a wheeled rover with equivalent sensing instrumentation would require, according to Bruhn.
"Our inflatable rovers are lightweight, travel great distances, use very low energy and will be fairly cheap," said Bruhn, who initiated the idea that has now been developed by a team of engineers. "One battery charge will let such a rover travel around 100 kilometers," he added.
The technology would allow the descendents of NASA's Spirit and Opportunity Mars rovers to carry mini-rovers of their own - dispatching them to scout out new sites of scientific interest.
Bruhn is confident that the idea will work because a larger (though not inflatable) version of the spherical robot technology, made by Rotundus of Stockholm, is already up and running.
That company's spherical 'Groundbot', is currently being tested for use in security and surveillance applications by the defence division of Saab.
"It can happily patrol large areas like harbours, travelling on snow, sand or gravel - it doesn't matter what the surface is," Bruhn told New Scientist.
The inflatable version of the robot would comprise an inflatable shell made of an ultra-strong plastic commonly used in space flight applications that's capable of withstanding high temperatures.
Inside it, a hollow metal axle stretches from one side of the sphere to the other, supporting all of the rover's electronics on a pendulum that hangs off it.
Bruhn's design team, which includes engineers from Uppsala University and NASA's Jet Propulsion Laboratory in Pasadena, California, US, envisages two landing scenarios for the robots.
In one, a lander or large rover can land as normal and then inflate and deploy the spherical scouts when they are needed.
"They would make a very good complement to a wheel-based robot, traveling at up to 30 kilometres per hour on sand and loose, gravelly solid surfaces - and giving scientists many more chances to see where the best science can be done," said Bruhn.
In another, less likely scenario, an orbiter arriving at Mars could inflate a flock of rovers and dispatch them into the atmosphere, with a heat shield to protect them from atmospheric heating.