STEVE INSKEEP, host:
The experience of the Mars rover highlights the trouble that robots can get into when they're far away from human help. That is one reason scientists would like to create robots that can fix themselves or even build their own replacements. Now some scientists say they've come up with primitive robots that can self-replicate. NPR's Nell Boyce has more.
NELL BOYCE reporting:
When people see the little robot in Hod Lipson's lab at Cornell University, they usually have the same reaction.
Mr. HOD LIPSON (Cornell University): The first impression of most people is that this is not a robot.
BOYCE: That's because his robot is just a stack of three white plastic blocks. They make a simple tower about a foot high. It looks like a toy, but then the tower starts to move.
(Soundbite of robot)
Mr. LIPSON: And gradually, the structure will bend itself over, twist in various ways. It is a bit interesting to watch how it changes its shape.
BOYCE: Each cube is split diagonally in half. Tiny motors and magnets allow it to swivel and hook up with its neighbors. Every cube also has an electronic brain that holds a blueprint for building new towers. That means that if you feed one tower more cubes, it will copy itself in just a couple of minutes.
(Soundbite of robot)
Mr. LIPSON: One of the things it can do is it can kind of bend down, pick up a cube on the side, bring it to the right place and drop it off.
BOYCE: Now reproduction is something that living things, like birds and bees, do all the time. But scientists have struggled for years to build machines that can reproduce. That's why Lipson's robot, described in the current issue of the journal Nature, is getting attention. Some scientists dream of building a single self-replicating explorer robot. It could travel to a distant planet, where it could clone itself. Lipson says his robot is still way too dependent on humans to take that kind of journey.
Mr. LIPSON: The robots are very limited in their ability to self-reproduce. They're dependent very much on having cubes supplied at a very particular place and a very particular time. Basically, they have a lot of constraints.
BOYCE: Other researchers are struggling with similar constraints. Gregory Chirikjian works at Johns Hopkins University. He makes robots from LEGOs. They also put together just a few ready-made parts. Chirikjian says his LEGObots aren't what people imagine when he tells them he's building self-reproducing robots.
Mr. GREGORY CHIRIKJIAN (Johns Hopkins University): In the general public consciousness, the idea is that it's a collection of robots that are somehow taking very basic parts, like nuts or bolts, and individually screwing them together to make these very, very complicated anthropomorphic C-3PO-like robots.
BOYCE: Researchers dream of building that kind of more complex, self-sufficient machine, but Chirikjian knows that this vision inevitably leads to fears about robots running amok.
Mr. CHIRIKJIAN: When I describe it to most people, they're worried about armies of robots making more and more things that are going to take over the world, and that's not at all what we're doing.
BOYCE: What they are doing is trying to design a self-copying robot made out of a dozen parts, instead of just three or four. Nell Boyce, NPR News.