Civilian drones may someday deliver your pizza, but they'll also travel places that people can't easily go, mapping forest fires or natural disasters, tracking wildlife, and studying Mars.
The further drones go, the more it might make sense to construct them out of biological materials. A new bio-drone could eventually be able to grow itself in remote locations, and if it gets lost in the wilderness,melt into a harmless puddle.
The shell of the drone is made from a mushroom-like material called mycelium, and cellulose coated with the same protein used to make wasp nests waterproof. Inside, the circuit board is printed with silver. Most of the materials—apart from a few components, like the motor—are biodegradable.
"If it crashes in an environmentally-sensitive place, such as a coral reef, then it can biodegrade and it won't affect the coral as strongly," explains Ian Hull, a sophomore at Stanford University, who was part of a large team of students from Brown, Spelman, and Stanford who collaborated with researchers from NASA on the design of the prototype.
"We can also send it into environments where we might not expect it to return," he says. "If we want to fly it over wildfires to see where it's spreading, or if there's a nuclear meltdown and we want to fly in to see what's going on with the radioactivity, we can send in the drone and it can send back data without returning."
The mushroom material proved to be well-suited for flying. "Mushroom materials are inherently lightweight, biodegradable, and the strength to weight ratio of the material was preferable for this application," says Melissa Jacobsen from Ecovative, the company that helped the students make the chassis.
Though the material would naturally biodegrade on its own, the students designed it to self-destruct. "It won't degrade very quickly unless we give it a set of enzymes that will help break it down further," says Hull. "Part of our project was making those enzymes that would only trigger upon certain conditions such as impact or time."
The bio material is also ideal for space, since in can grow itself, no matter where it is. "The problem with trying to bring anything to space is it's expensive to take mass up there, and you want anything you bring to be easily modified," says Hull. "Instead of taking parts and backups, you can just take a tiny sample of the bacteria or fungus you need to grow something like this drone."
The drone can also use bio-engineered sensors, which can help reduce weight and eliminate the need for electric power. Other bio-engineered cells, developed from organisms that live in extreme environments, help protect the drone from high temperatures and radiation. The students carefully changed the cells so they wouldn't affect the environment if the drone crashes and melts.
The drone was one of this year's entries in the International Genetically Engineered Machine competition.