PORTLAND, Ore. — Astronauts can only endure space for about six months without irreversibly damaging their muscles, despite daily exercise. Unfortunately, it will take at least 30 months of space travel to reach Mars, making a manned flight unfeasible today.

The National Aeronautics and Space Administration (NASA) recently reported progress toward a neural implant technology using carbon nanotubes that could enable space flights of indefinite periods.

By stimulating the neural pathways responsible for muscle atrophy, NASA hopes to fool the brain into thinking that gravity is still present even in free fall. "We hope to let the brain feel the weight of gravity, even if it's not there," said NASA scientist Jun Li. "For a trip to Mars, we could monitor astronauts' brains, then artificially stimulate its neurons with nanofiber electrodes to fool it into thinking gravity is still working."

The project has been ongoing for about two and a half years at NASA's Ames Research Center in Moffett Field, Calif. Scientists are working to develop a biocompatible implant that can interface to the brain as a prosthetic device that both monitors neural activity and stimulates neural tissue as necessary. The resulting vertically aligned carbon nanofiber (VACNF) electrodes could also be helpful on Earth for biosensors, medical implants to combat Parkinson's disease, as well as an anti-atrophy stimulator for deep-space travelers, according to Li.

"We have learned a lot from others' successful cochlea implants, artificial retinas and medical prosthetics implanted into the brain to stimulate neural pathways that combat Parkinson's disease and epilepsy," said Li. "Now we think we have improved on those designs and are ready to prove it by trying out our implants in live subjects."

NASA has experimented on the brain tissue of rats and reports that their tests show a 10-fold increase in efficiency, compared with conventional electrodes. Next, they plan to test their nanofiber electrodes in the brains of live rats and measure both electrical characteristics and synaptic chemical neurotransmitters.