Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100

self-replicating robots to the moon. There, the robot would use the soil and create unlimited copies of itself.
    Most of the report was devoted to the details of constructing a chemical factory to process moon rocks (called regoliths). The robot, for example, might land on the moon, disassemble itself, then rearrange its parts to create a new factory, much like a toy transformer robot. For example, the robot might create large parabolic mirrors to focus sunlight and begin melting the regoliths. It would then use hydrofluoric acid leeching to begin processing the regoliths to extract usable minerals and metals. The metals could then be fabricated into the moon base. Eventually, the robot would construct a small moon factory to reproduce itself.
    Building on this report, in 2002, NASA’s Institute for Advanced Concepts began funding a series of projects based on these self-replicating robots. One scientist who has taken seriously the proposal of a starship on a chip is Mason Peck of Cornell University.
    I had a chance to visit Peck in his laboratory, where you could see his workbench filled with components that may eventually be sent into orbit. Next to his workbench was a small, clean room, with walls draped in plastic, where delicate satellite components are assembled.
    His vision of space exploration is quite different from the one given to us by Hollywood movies. He envisions a microchip, one centimeter in size and weighing one gram, that could be accelerated to 1 percent to 10 percent of the speed of light. He takes advantage of the slingshot effect that NASA uses to hurl spacecraft to enormous velocities. This gravity-assist maneuver involves sending a spacecraft around a planet, like a rock from a slingshot, thereby using the planet’s gravity to increase the spacecraft’s speed.
    But instead of gravity, Peck wants to use magnetic forces. His idea is to send a microchip spaceship whipping around Jupiter’s magnetic field, which is 20,000 times greater than the earth’s field. He plans to acceleratehis nanostarship with the magnetic force that is used to hurl subatomic particles to trillions of electron volts in our atom smashers.
    He showed me a sample chip that he thought one day might be hurled around Jupiter. It was a tiny square, smaller than your fingertip, crammed with scientific circuitry. His starship would be simple. On one side of the chip, there is a solar cell to provide energy for communication. On the other side, there is a radio transmitter, camera, and other sensors. The device has no engine, since it is propelled using only Jupiter’s magnetic field. (NASA’s Institute for Advanced Concepts, which funded this and other innovative proposals for the space program since 1998, was unfortunately closed in 2007 due to budget cuts.)
    So Peck’s vision of a starship is a sharp departure from the usual one found in science fiction, where huge starships lumber into space piloted by a crew of daring astronauts. For example, if a base were set up on a moon of Jupiter, then scores of these tiny chips could be fired into orbit around that giant planet. If a battery of laser canons were also built on this moon, then these chips could be accelerated by hitting them with laser light, increasing their velocity until they reached a fraction of the speed of light.
    I then asked him a simple question: Can you reduce your chips to the size of molecules using nanotechnology? Then, instead of using Jupiter’s magnetic fields to accelerate these chips, you could use atom smashers based on our own moon to fire molecular-sized probes at near the speed of light. He agreed that this would be a real possibility, but that he hadn’t worked out the details yet.
    So, we took out a sheet of paper and together began to crank out the equations for this possibility. (This is how we research scientists interact with one another, by going to the blackboard or taking out a sheet of paper to solve a problem by writing down the equations.) We wrote down the equations for the Lorentz force, which Peck uses to accelerate his chips around Jupiter, but then we reduced the chips to the size of molecules and placed them into a hypothetical accelerator similar to the Large Hadron Collider at CERN. We could quickly see that the equations allowed for such a nanostarship to accelerate to nearly the speed of light, using only a conventional atom smasher based on the moon. Because we were reducing the size of our starship from a chip to a