It’s a bird, it’s a plane … it’s a robo-puffin?

Birds like gulls and puffins can effortlessly move between air and water, a feat that seems impossible due to the vast difference in density between the two mediums. Water is 1,000 times denser than air, meaning movement requires entirely different mechanics in each environment. Yet these birds dive into the sea, swim underwater, and then fly back into the air as if it were routine. Engineers at MIT and EPFL in Lausanne, Switzerland, were inspired by this ability and designed a robot that mimics these actions. The robot, called the flapping-wing aerial-aquatic vehicle (FAAV), weighs less than 300 grams—about half a pound—and is equipped with a central body, two flexible wings, and a steerable tail. The wings are made of thin membranes coated with hydrophobic nanoparticles to repel water, while the tail helps control movement in both air and water.

The FAAV operates using a waterproof electric motor and a crankshaft that drives the wings up and down at preset frequencies. The body contains a battery to power the system. The wings are designed to be flexible enough to minimize flapping in water but firm enough to generate lift in air. The robot’s tail is motorized, allowing it to change its angle to help the robot dive or ascend. In experiments conducted in a water tank and at Lake Geneva, researchers led by Raphael Zufferey, an assistant professor of mechanical engineering at MIT, found that medium-sized wings and a tail angle of 70 degrees enabled the robot to smoothly transition from swimming to flying. Surprisingly, the robot did not require feet to take off from water, unlike many diving birds that use their feet to paddle.

The engineers envision the FAAV as a tool for scientists and researchers who need to collect data from aquatic environments that are difficult or dangerous to access with traditional methods. Zufferey suggests that oceanographers, marine biologists, and coastal communities could use the robot to launch it from a boat or shore, fly it to an area of interest such as an iceberg or a pod of whales, dive into the water to take measurements or collect samples, and then fly back to deliver the data. This could be done at a fraction of the cost of traditional methods. The robot could potentially operate multiple times in a single day, flying out at high speeds, diving, and returning with data every hour. This frequent and widespread data collection could address one of the major challenges in ocean science: gathering data both frequently and across many locations.