Swarms of Nano-nauts
Meet the Nano-Nauts: Smart Dust Swarms for Planetary Exploration
Engineers at the University of Glasgow are designing a new breed of planetary explorers: tiny, shape-shifting devices that can be carried on the wind like dust particles but are also smart enough to communicate, fly in formation and take scientific measurements.
Smart dust particles consist of a computer chip, about a millimeter in dimension, surrounded by a polymer sheath that can be made to wrinkle or smooth out by applying a small voltage. Roughening the surface of the polymer means the drag on the smart dust particle increases and it floats higher in the air; conversely, smoothing out the surface causes the particle to sink. Simulations show that by switching between rough and smooth modes, the smart dust particles can gradually hop towards a target, even in swirling winds.
Dr John Barker, who described possible applications of smart dust at the RAS National Astronomy Meeting in Preston on 18th April said, "The concept of using smart dust swarms for planetary exploration has been talked about for some time, but this is the first time anyone has looked at how it could actually be achieved. Computer chips of the size and sophistication needed to make a smart dust particle now exist and we are looking through the range of polymers available to find one that matches our requirements for high deformation using minimal voltages."
Smart dust particles would use wireless networking to communicate with each other and form swarms. Dr Barker explains, "We envisage that most of the particles can only talk to their nearest neighbors but a few can communicate at much longer distances. In our simulations we’ve shown that a swarm of 50 smart dust particles can organize themselves into a star formation, even in turbulent wind. The ability to fly in formation means that the smart dust could form a phased array. It would then be possible to process information between the distributed computer chips and collectively beam a signal back to an orbiting spacecraft."
In order for the smart dust to be useful in planetary exploration, they would need to carry sensors. With current technology, chemical sensors tend to be rather large for the sand-grain sized particles that could be carried by the thin Martian atmosphere. However, the atmosphere of Venus is much denser and could carry smart sensors up to a few centimeters in size. Dr Barker said, "Scientific studies could theoretically be carried out on Venus using the technology we have now. However, miniaturization is coming on rapidly. By 2020, we should have chips that have components which are just a few nanometers across, which means our smart particles would behave more like macro-molecules diffusing through an atmosphere rather than dust grains."
The group at Glasgow thinks it will be some years before smart dust is ready to be launched into space. Dr Barker said, "We are still at an early stage, working on simulations and components. We have a lot of obstacles to overcome before we are even ready to physically test our designs. However, the potential applications of smart dust for space exploration are very exciting. Our first close-up studies of extra-solar planets could come from a smart dust swarm delivered to another solar system by ion-drive." It may be a long way off, but one day smart dust could provide a unique method of collecting data on some of the most important and exciting locations for astrobiology research.
Smart dust was developed by Kris Pister, Joe Kahn, Bernhard Boser at the University of Berkley, California, between 1998 and 2001 with the aim of demonstrating a complete sensor/communication system that could be integrated into a cubic millimeter package. Glasgow University is a member of a large consortium dealing with a practical variant called Smart Specks.