September 4, 2021. By Kolemann Lutz
Microelectromechanical systems (MEMS), or smart dust, are small wireless microrobots 20micrometers - millimeters in size equipped with sensors, cameras, and other transceivers that can wirelessly collect vast amounts of data such as light, vibrations, temperature, pressure, acceleration, humidity, sound, and stress. MEMs operate with a very small power supply that can process, store, and wirelessly transmit and ping data to the cloud, computers, other MEMS or other IoT devices.
MEMS could collect data for agriculture, equipment screening, maintenance, assessing condition of machines, corrosion, inventory monitoring, medical diagnostics, transportation logistics, pavement maintenance, and temperature of roads. Another idea involves mixing the particles into concrete to internally monitor the health of buildings and bridges and even monitor various loads and forces acting on structures.
Dr John Barker, from the University of Glasgow proposes a detailed plan for the use of such microrobots to study other planets, in particular Mars.
Smart dust could be packed into the nose cones of planetary probes and then released into the atmospheres of planets, where they would be carried on the wind. For a planet like Mars, smart dust particles would each have to be the size of a grain of sand for flight in the wind-dominated environment of the Martian landscape.
Each MEMS system will be enveloped by a thin polymer film to enable changing shapes very quickly and efficiently under the influence of very low electrical impulses. By applying electric current to alter the shape of the polymer sheath surrounding the chip, dust particles could be steered towards a target to float with wind and to form an organised swarm.
Wrinkling the plastic sheath would increase the drag coefficient on the particle, lifting it higher in the wind. Flattening out the sheath would cause the particle to decrease in altitude, yielding improved precision flight trajectories.
"In our simulations, we have shown that a swarm of 50 dust particles can organise themselves into a star or spherical formation, even in turbulent wind." mentioned by Dr John Barker, from the University of Glasgow.
Similar to chipsats, the ability to fly in formation would allow the processing of data to be spread over longer distances, or "distributed" between all the chips, and a collective signal to be beamed back to a mothership in-orbit.
In a 2008 Conference in Boston On Swarm Intelligence and Smart Dust, Professor Barker published a study and presented research that found that the perimeter and not the surface area of the flier is the key factor in determining the force experienced during flight. Harvesting local power has been investigated for: solar power, microwave absorption and collisional self-charging but hostile terrain and weather remains a challenge.
Today’s sensors are too large for particles the size of sand-grains that might be carried by the Martian wind for deployment. But the denser atmosphere of Venus could carry particles up to a few centimeters in size. MEMS components should reach sizes of a few nanometers across, that would behave more like molecules in atmosphere rather than dust grains.
3D printing with stereo-lithography, two photon lithography, and thin film deposition on the microscale could enable significant price reductions and scalable production of ultra lightweight MEMS to support the data collection for human settlement on Moon, Mars, and Venus.
Acknowledging that smart dust is years away from deployment on an actual mission, Barker looks well down the road at interstellar implications: “Our first close-up studies of extra-solar planets could come from a smart dust swarm delivered to another solar system by ion-drive.”
Further research will be required to investigate the feasibility of stowing and deploying nanodust sensors and microrobots from interplanetary solar sails to Alpha Centauri.
Untethered micro fliers propelled by radiometric forces could reduce cost of imaging planetary surfaces and geology to democratize permanent settlement and expansion of life throughout the Solar system and cosmos.
Barker, J.R. and Rodriguez-Salazar, F. (2008) Self-organizing smart dust sensors for planetary exploration. In: Workshop on Nanosensors: Self-Organization and Swarm Robotics, Boston, Massachusetts, USA, 14 Sept 2008, http://eprints.gla.ac.uk/48536/
