Corrosion Resistant Aerial Covert Unmanned Nautical System

A new drone from researchers at Johns Hopkins University is going where many unmanned aerial vehicles cannot: underwater.

The submersible drone, which has a mouthful of a name — the Corrosion Resistant Aerial Covert Unmanned Nautical System (or CRACUNS) — can "stay on station beneath the water, then launch into the air to perform a variety of missions," according to a news release. Developed and tested by researchers within the university's Applied Physics Laboratory in Laurel, Md. with internal funding, the CRACUNS prototype promises to offer new capabilities not possible with existing unmanned aerial or underwater vehicles.

"The most innovative feature of CRACUNS is that it can remain at and launch from a significant depth without needing structural metal parts or machined surfaces," the researchers said. So, basically this thing can operate effectively in the air and underwater.

The team needed to overcome two major challenges to make this happen: water pressure and corrosion. Leveraging "advances in additive manufacturing and novel fabrication techniques," they managed to create a "lightweight, submersible, composite airframe" that can withstand water pressure. To combat corrosion, they sealed the most sensitive components in a dry pressure vessel and applied commercially available protective coatings to the motors that are exposed to salt water.

Then, they tested the coated motors by submerging them in salt water. Two months later, they showed no signs of corrosion, and they still worked.

"CRACUNS successfully demonstrated a new way of thinking about the fabrication and use of unmanned systems," APL's Rich Hooks, an aerospace and mechanical engineer who devised the additive manufacturing techniques used on CRACUNS, said in a statement.