With a history of productive lander missions, two healthy spacecraft currently in Mars orbit and the unqualified success of the Mars Pathfinder mission, it would be easy for NASA to just continue with more of the same. Future Mars orbiters, landers and rovers are in development, but NASA is also working on the next generation of hardware and software solutions for more advanced unmanned exploration.

'Bot'-ing Around Some New Designs

NASA is currently investigating innovative designs such as Snakebots, which move across desert terrain like a sidewinder snake, and Frogbots, which can propel themselves with a hopping motion.

Bulldozer rovers that operate like miniature excavation teams and beachball-like Tumbleweed rovers that will blow across the Martian surface are examples of less costly and more efficient robotic designs now undergoing tests at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

Where's the Water?

The search for evidence of water on Mars is of primary interest to planetary scientists. As more information from Mars Global Surveyor provides increasing evidence that water resources may be concentrated near Martian cliff edge outflows, with the possibility of rich water-borne mineral deposits that extend all the way to the cliff base, NASA is working toward robotic means for exploring these difficult-to-reach sites. Enter JPL's latest rover concept, the Cliff-Bot.

"We're trying to go where no robot has gone before," said Dr. Paul Schenker, Supervisor of the Mechanical and Robotic Technologies Group at NASA's Jet Propulsion Laboratory. "There are areas on the surface of Mars that we think to be very rich with new geology, mineralogy and atmospherics that current robots can't access. So we're trying to develop a new type of rover, more intelligent, more agile, to get to these regions."

Current rovers can only traverse grades of 15 to 20 degrees. Schenker and his team are working on rovers that can traverse near vertical cliff-like terrain. This will allow close investigation of areas such as the cliff edge outflows imaged by the Mars Global Surveyor.

Schenker described how the robots work: "The Cliff-Bot is a system of three robots, two of which stand above a cliff edge, one below. They work autonomously and cooperatively together to let the Cliff-Bot itself (the lower robot) descend and ascend to do cliff face exploration."

This technology could also have useful applications here on Earth. "They're capable of rappelling down and climbing up very steep rocky inclines and this is bound to have importance in the future, to such applications as Search and Rescue," Schenker added.

Greater Cooperation Among Machines

Researchers at NASA's JPL have recently demonstrated the first use of multiple rovers working in synch to perform tasks such as coordinated grasping, lifting and moving of an extended payload while navigating through obstacles on natural terrain. These Robotic Work Crews demonstrated the simulated deployment of a solar power station, as two cooperating rovers autonomously approached, gripped and carried a 2.5 meter (8 foot) long container over distances of more than 50 meters (164 feet).

While these robots are more mechanically advanced than their recent predecessors, the cooperative systems are the big changes over recent designs used on Mars Pathfinder's Sojourner rover.

"We're not asking one rover to go out and do a local area exploration, but rather multiple robots to autonomously do rather human-like tasks," Schenker said. "Here we have an evolution of sensory intelligence, of control intelligence and cooperation among assets.

"Think about the promise of that for the future, where we eventually look towards planetary exploration that has multiple vehicles, landers, stations, all working in a rich network environment for a sustaining presence," Schenker continued. "This is a major step in that direction. It's the beginnings of a computing architecture, a network robotic capability that will lead us towards the definition and development of that kind of future planetary system."

The vision is to bring more autonomous intelligence, longer operations without human supervision and increased mission capabilities to the future. The All Terrain Explorers will take us to places we've never gone before. Once NASA determines there are the right resources on Mars for long-term habitation, robot work crews would help pave the way for people to join the robotic teams.

Eventually, the software developed in this research has potentially broad applications beyond Mars exploration, wherever robotic vehicles must work closely together. As an example, it could someday be used to control a constellation of multiple satellites that search for distant planets.

The Future

Although initial tests on Earth have been successful, this technology is still in the early stages of development. It will take about 10 years or more for these systems to mature enough to be chosen for flight applications. With further Mars landers and rovers currently being readied for flight and many more robotic explorers under development, NASA's vision for extensive unmanned exploration of the Red Planet is now coming into focus.

Before we can make the next "giant leap for mankind", we need to have a far better understanding of Mars. All Terrain Explorer technologies like Cliff-Bot will provide mission planners with information to help select landing sites for future missions that hold the greatest potential for scientific discovery.

Over the next decade, NASA missions will continue to gather vital information needed to assure the successful human exploration Mars. Such a critical new understanding of the Red Planet will be the direct result of an armada of orbiting, roving, rolling, grasping and climbing robots that will be exploring Mars in the years ahead.

Robert "Chuck" Marble runs Marble Productions, which specializes in non-profit multimedia space science presentations.