By Dean Irvine for CNN
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LONDON, England (CNN) -- Posted October 16, 2006
As Nasa's Martian robot, Opportunity, wheels its way around the edge of the Victoria crater, a new breed of automaton is being developed that could provide a great leap forward, literally, in robotic exploration.
Microbots, small spherical robots able to hop over a planet's rugged terrain could become the front line in planetary exploration in ten years time, according to Professor Steven Dubowsky and his team at the Field and Space Laboratory at the Massachusetts Institutes of Technology.
The main advantage of these microbots, each slightly larger than the size of tennis ball, would be their ability to venture into the cracks and crevices of a planet such as Mars or the moon, where other robots cannot reach.
"We don't see these microbots as a replacement for rovers, but as complementary explorers that could be used to serve a number of purposes," Dubowsky told CNN.
"They could operate as scouts and cover large areas looking for materials or sites that would warrant further investigation by larger robots capable of carrying more equipment."
The hopping movement would allow the mini robots to leap over obstacles, if not in a single bound, at least in increments. Dubowsky and his team envisage a swarm of microbots working in a team.
The devices would travel approximately 1.5 meters with each hop, at an average of six hops per hour. They could also roll and bounce over remote and rocky terrain.
A swarm of microbots sent to investigate a particular area then could cover 50 square miles a day.
The microbots' hop is produced by a small foot that extends and retracts from the bottom of the sphere. By incorporating a stability system to keep the bot the right way up, the device is designed to store and release energy.
Made of durable plastic to withstand the harsh landscape of either Mars or a planetary moon, the microbots would be powered by a small fuel cell that would provide enough heat to keep their sensors and electronics operational in conditions, that should they be deployed on Mars, which can fluctuate by 70 degrees centigrade in a day.
"We have the fuel cell down to the size of a postage stamp with it producing a fraction of a watt of energy," said Dubowsky.
This might seem a small amount by today's standards of fuel cell technology -- some of which are being developed for use in cars and laptops of 5 watts -- but it is enough to power the bistable foot of a microbot for long range missions of around 100 hops.
The project has received Phase 2 funding from Nasa's Institute for Advanced Concepts that will run until 2007 and the current prototype is already hopping around the lab, according to Dubowsky.
However the aim is to test the probes in the field next fall. The MIT team have been working with Dr Penelope Boston of New Mexico Tech, where the test will be undertaken next year in the caves of New Mexico.
Martian lava tubes -- the tunnels left behind from underground lava flows - and canyons have been identified as the perfect place for the spelunking bots to investigate as they are promising locations for the discovery of water on the Red Planet.
Sending a swarm of microbots down a lava tube from it's opening on the surface would be one of the only ways to explore these otherwise inaccessible locations.
Current rover robots, like Opportunity and Spirit on Mars, need a flat area to land and must avoid tipping over. A single mishap could jeopardise a whole mission and cost a space agency hundreds of millions of dollars.
By employing microbots in large numbers, even the loss of a few hundred or a thousand of them would not derail a mission.
"In such a hostile environment, the microbots would have a sacrificial use," Dubowsky told CNN. "You wouldn't mind sending a thousand or so of these robots into an environment where they wouldn't return from if you knew that you could gather evidence."
Working as a team the probes would be able to communicate with each other, relaying data via a local area network from those bots at the front of the chain to those further back that would then transmit the data back to base.
While this wireless technology can already be found in many domestic homes and offices, the power sources and instruments contained in the mini robots is a key point of the team's research.
Their size naturally limits how many sensors or devices they could carry -- some may be equipped with tiny cameras, others with chemical sensors or ion-selective electrodes for gases.
The versatility of the mini robots even extends to how they could be deployed. Nasa's rover Opportunity is approximately the same size and weight as a golf buggy. For a similar size and weight, 1,000 microbots could be launched.
"They could be carried by rovers or air launched from orbiting probes above the planet's surface. They could even be carried in an astronaut's backpack and thrown into an area or cave by hand," said Dubowsky.
Some experts, such as Dr. Charles Elachi of Nasa's Jet Propulsion Institute believe that smarter robots will shape the future of robotic space exploration.
"Robots will have some level of intelligent decision making in the future. It exists already on Spirit and Opportunity, where if we command them to do something and they find a risk doing it, they will not do it. They will stop and say,' wait a minute, are you sure you want me to do this?'," Elachi told CNN.
This may be a hop to far for the microbots as they take a more collective approach to operating, but these mini foot soldiers of planetary exploration may well serve a vital link in the future discoveries of our solar system's moons and planets.
A swarm of microbots could explore inhospitable areas other robots or humans could not reach.
The microbot would hop uisng a extendable foot, part of a sophisticated onboard balance and mobility system.
No bigger than the size of a baseball, the microbots could be deployed in huge numbers.