April
2007
Meet the nanonauts0
Teaching resources (UK US) designed specifically for this story at Real Science
The story
Tiny, shape-shifting devices that are carried on the wind like dust, but are smart enough to communicate, fly in formation and take scientific measurements. Sounds like science fiction? Not at all, say engineers at the University of Glasgow, who are designing a new breed of planet explorers.
Smart dust particles contain a computer chip one millimetre across. This is surrounded by a polymer sheath that a small voltage can make wrinkled or smooth.
Roughening the surface makes the drag on the smart dust particle increase and it floats higher in the air. Smoothing out the surface causes the particle to sink. Simulations show that by switching between rough and smooth, the smart dust particles can hop towards a target.
Professor John Barker will talk about possible applications of smart dust at the RAS National Astronomy Meeting in Preston today, 18 April. “The concept of using smart dust swarms for planetary exploration has been talked about for some time,” he said.
“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.”
He and his team are studying a variety of polymers to find one that can give a large deformation for a small voltage, he added.
Smart dust particles would use wireless to communicate with each other and form swarms, Professor Barker explains. Most particles in the swarm can only talk to their nearest neighbours. But a few can communicate at much longer distances.
“In our simulations we’ve shown that a swarm of 50 smart dust particles can organise themselves into a star formation, even in turbulent winds.
“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.”
For smart dust to explore a planet, the particles need to carry sensors. Today’s chemical sensors are too big for the thin Martian atmosphere. This could only support particles the size of sand grains.
But the atmosphere of Venus is much denser. It could carry smart sensors up to a few centimetres in size. “Scientific studies could theoretically be carried out on Venus using the technology we have now,” says Professor Barker.
“However miniaturisation is coming on rapidly.”
By 2020 chips will be available with components just a few nanometres across, he said. “This means our smart particles would behave more like macro-molecules diffusing through an atmosphere, rather than dust grains.”
The Glasgow group believes it will be some years before smart dust is ready to be launched into space. “We are still at an early stage, working on simulations and components,” said Professor Barker. “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.”
Topics for group discussion or pupil presentations
1. Figuring out exactly what scientists have been doing on the basis of news stories is often quite difficult. A useful starting point is an activity that asks students to classify the different types of statement in a story. In groups students should look for all the occurrences of just two types of statement in this story: a) technology and methods used by the scientists, and b) new findings or developments they have made.
Students should then try to answer the following questions:
- In as much detail as possible, what do these Glasgow scientists actually do when they come into work each day?
- How has what they have been doing made the manufacture of smart dust more likely?
2. In groups, students should assess the merits of manned versus unmanned space exploration. Human spaceflight is costly, dangerous, and a complete waste of time and money, say critics. Supporters point out that the urge to explore is part of what makes us human. The key difference between people and robots (including smart dust) in space is that we care about people. It is hard to identify with the adventures of dust, no matter how smart it might be. So space exploration needs people up there to win support and funding from governments and the general unscientific public. Discuss.
3. One of the most astonishing sights in nature is a flock of starlings at evening-time, flying in formation, swooping and swirling in mesmerising patterns that seem to be controlled by just one mind. It’s one example of a phenomenon called emergent behaviour, which is quite widespread in the natural world. The scientists in this story are aiming to exploit the emergent behaviour of smart dust particles.
Students should find as many examples in the natural world as they can, and prepare a short presentation which touches on how one controlling mind can seem to emerge when individuals communicate only with their nearest neighbours.
Links to free activities, resources and lessons
This story is about science just beyond the limits of today’s technology, so the Web offers few relevant classroom activities. The following is a set of sources of accessible information on smart dust and its applications.
Professor Barker on smart dust research at Glasgow University. Includes entries on space applications, shape changing and the analogy with blown sand.
City-swallowing sand dunes. Nice illustrated story and audio of how particles of sand move by a method known as saltation. This is the most likely mode of travel for the first generation of smart dust.
“Swarms of smart dust might be packed into nose cones of planetary probes and subsequently ejected into the atmosphere of a planet where they would be carried by the wind. For a planet such as Mars smart dust motes would each be of the size of a grain of sand.” From Professor Barker’s website.
Notes and thoughts on a smart dust project at Berkeley.
Website of a company set up to commercialise smart dust.
“We have considered the collective movement of motes towards a target located in a portion of the Martian surface that extends over a range of several kilometres.” Professor Barker again.
The smart dust project. “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 can be integrated into a cubic millimetre package.” Glasgow University is a member of a large consortium dealing with a practical variant called Smart Specks.
Daily tip for science class discussions and groupwork
Listening to each other is not merely a matter of being quiet when another person speaks; listening requires a response to what is being said. Teachers could develop procedural guidelines to give structure to group talk so that children become used to questioning and challenging each other. The consistency in performance of one group in the study suggests that the children may have developed certain ground rules for the argumentation process, as they knew how to work together collaboratively. The inconsistent performance shown by other groups suggests that although they were capable of high levels of argumentation, they had no such ground rules. If children are able to scaffold small-group discussions themselves then the teacher input could be directed towards children who are not yet capable of doing this.
Simon, S. and Maloney, J. (2007) Activities for promoting small group discussion and argumentation. School Science Review, 88 (324), pp. 49-57
