Virginia Tech: Autonomous Robotic Jellyfish from virginiatech on Vimeo.

This five-and-a-half-foot robot jellyfish could be the future of Navy underwater surveillance. Seriously. Maybe. Certainly, if a team of engineers from Virginia Tech gets its way.

Meet the Cyro, an autonomous robot with eight mechanical legs ringing its metal chassis, designed to mimic the unique, efficient underwater propulsion of a jellyfish. Covered in silicone to replicate the jellyfish's wavy, bioluminescent mesoglea – the jelly, basically – the Cyro weighs a staggering 170 pounds, all thanks to a five-year grant from the Office of Naval Research.

The robot is still a prototype, years away from being in the water. But it represents a new kind of testbed for oceanographic surveillance, the Cyro's basic application. Like the bird- and insect-shaped drones the Air Force is developing, a jellyfish-like spybot has a natural stealth advantage. "Mimicking a natural animal found in a region allows you to explore a lot better," says Alex Villanueva, a graduate student at Virginia Tech working on the Cyro.

It's a much different model for underwater propulsion than the Navy's used to. Jellyfishes move, uniquely, by flapping themselves about. "It's not necessarily the best hydrodynamics propulsion mechanism, but the jellyfish has a very efficient metabolism: energy going in comes out as hydrodynamic energy," Villaneuva says. The Cyro isn't there yet, but it gets three to four hours of swimming time out of its rechargeable nickel metal hydride battery.

And it's also a launch-and-forget robot. There's no remote controls on the Cyro. Place it into the water, and its roll-pitch-yaw sensor package, pressure sensors and software do the rest. That's something for the Navy to think about as it considers designs for its forthcoming unmanned underwater vehicle fleet.

There's no saying whether the Navy will purchase the 'bot, and its inventors are comfortable emphasizing its civilian potential as an oceanographic research testbed. But should the Navy decide it needs a surveillance tool that looks like a massive jellyfish, there's one on offer.