US Navy's solar drone flies from and lands on water

It could be used to hunt for enemy submarines.

Unlike most quadcopters, the Aqua-Quad doesn't take off from solid ground. Dr. Kevin Jones and his team from the Naval Postgraduate School developed it to fly straight up from the ocean or any body of water. And it can land back on water after it has fulfilled its mission, staying on or under the surface until it's deployed again. According to New Scientist, the Aqua-Quad (PDF) could be used to replace sonobuoys to search for submarines, especially enemy subs that might be lurking in the depths of the country's oceans.

They're even better than the actual expendable sonar systems, because they're not constrained by battery life: the drone's rotors are covered in solar cells and can generate power after a little time under the sun. In addition, it can hunt for subs in flocks in case the Navy wants to scour a big area more quickly. Jones told the publication that as a sonobuoy replacement, the drone "[will] be on the water 23 hours a day, and flying maybe one hour a day." It was designed as a "launch and forget" system with a water-tight enclosure, though, so we're guessing it's tough enough to endure the ocean's harsh conditions.

Speaking of drones that can take off from water, researchers from the Johns Hopkins University Applied Physics Laboratory created a similar machine called CRACUNS. It can stay hundreds of feet underwater for months at a time until its operator sends it out to do his bidding.