Hancock, N.H. Micro-rovers that hop, fly or burrow; networks of ultrasmall probes dropped on a remote body such as an asteroid or planet; swarms of micro-spacecraft taking in massive amounts of data. Those are just some of the systems and applications envisioned by the researchers working at NASA's Center for Nanotechnology.
At the NASA Ames Research Center (Moffet Field, Calif.), more than 50 scientists and technologists are working on broad fronts to develop the potential of nanotechnology for space exploration. The overall thrust of their work is to develop miniaturized, lightweight materials and electronics systems. Reducing the size of the payload while increasing the intelligence of space probes would help NASA to do more with less, the researchers said.
"Nanotechnology presents a whole new spectrum of opportunities to build device components and systems for entirely new, bold space architectures," lab director Meyya Meyyappan writes in a progress report on the group's research. To that end, projects are under way to build nanotube sensors, molecular electronics, nanotube-based materials, quantum-computing systems and compu-
tational optoelectronics. The center's time line calls for putting systems in the field in 10 to 15 years.
Processing systems for nanomaterials are a key enabling technology. While visionaries expect the creation of nano-
bots that could assemble materials and systems at the atomic and molecular scales, that approach is too far in the future for NASA's current needs. For now, the nanomaterials aspect of the lab's work is looking at conventional, top-down materials processes to glean clues to practical processing techniques.
A two-pronged attack combines computer simulation of basic processes, such as chemical vapor deposition or plasma processing, with data derived from gas-phase, plasma-phase and surface chemistry experiments. The researchers hope an understanding of those basic processes will lead them toward novel materials for space vehicles that would not only be tough and lightweight but could also include sensors and electronic components on a molecular scale.
On one project investigating the physical and electronic properties of single-walled carbon nanotubes, a relationship between mechanical strain in semiconducting nanotubes and their bandgap was discovered. Carbon nanotubes could be assembled into extremely tough materials that would also have useful electronic properties because the nanotubes exhibit a variety of conducting and semiconducting capabilities, the researchers said.
Nanotube fabrication is also expected to yield molecular-scale motors. A simulation by one group showed how benzene molecules could be attached to a nanotube to form a gear. The nanotube functions as the axle and the benzene as the gear teeth. Assemblages of gears were also simulated, showing how one gear could drive another.