THEY whirr and clomp and stagger. They poke and dig and grab. Some look like spiders. Some look like frogs.
They are the forebears of the next generation of planetary explorers - the robot rovers that will boldly go where no human wants to go before them. When they strutted their stuff during the World Space Congress here last week, they drew more attention than the human astronauts and cosmonauts.
Rover Expo set up shop next door to the National Air and Space Museum, which joined the National Aeronautics and Space Administration (NASA) and the Planetary Society in sponsoring the exhibit. The robots included complex rovers that climb hills and crawl over boulders. They roll on wheels and walk on legs. Some even somersault over obstacles. There were also structures designed to test functions, for example, those of the National Institute of Standards and Technology's Spider.
The Spider looks like a frame built from an old Erector set with a scoop-carrying platform suspended from it. The purpose was to demonstrate remote operation of the platform. This was simple enough for a child to do, as a small boy happily illustrated.
But he was having no more fun then Lewis Friedman, executive director of the Planetary Society in Pasadedna, Calif., who enthusiastically conducted the rover show. Dr. Friedman has said he feels especially excited right now because he sees the rover-explorer concept moving rapidly toward mission status.
Last May, the Planetary Society joined with three Russian organizations to test a prototype rover for the Russian Mars 796 mission. The Russian organizations - Babakin Center of NPO Navochkin, Khimki, Institute for Space Research, Moscow, and Mobile Vehicle Engineering Institute, St. Petersburg - expect to have a flight model ready for the mission's launch in 1996. This now has become an international mission, with NASA included.
As displayed here, the Russian rover looks like an instrument-carrying cart on six titanium wheels that look like air bags instead of ordinary-looking wheels. It can travel through rough, boulder-strewn terrain with high mobility, according to the Planetary Society. Its designers say they may work with American counterparts to develop a rover for lunar exploration.
Some robots, like the Sandia National Laboratory's Raybot, work right here on Earth. Raymond Byrne - the "Ray" of Raybot - designed the vehicle as a general purpose test machine. But, he said, it has become useful in investigating accidents.
Rovers need optical, tactile, and sometimes chemical sensors. They need tiltmeters and accelerometers for balance and orientation. They may need grabbers and diggers and, maybe, drills or laser probes. They of course need power supplies. And, most of all, they need on-board computers to process all the data from their sensors and integrate it to produce appropriate actions.
Designers say they expect the technology to evolve in increasingly sophisticated ways that more and more will resemble human capacities. But they feel enough pride in what their present models can do to give them such pet names as Genghis, Spider, Ratler, and Rocky III. They also point out the more advanced capabilities that are are being built into machines. Carnegie Mellon University's Dante, for example, has a "mechanically intrinsic walking gait."
At one booth, a small biological unit was testing its own capabilities. It had optical, tactile, and chemical sensors. It had grabbers and diggers. It obviously had a mechanically intrinsic walking gait. And it had a data processing and control system that outclassed anything else in the exhibit.
This central command system has what engineers call self-learning capacity. In time, the stumbling gait could become a graceful waltz, the uncertain grip could one day guide an artist's brush.
Designers freely admit, though, that they cannot hope to give their machines the capabilities with which a human child is born.