A submarine's periscope is a useful reconnaissance tool, but it puts the vessel at risk since it can only be used when the sub surfaces. As an alternative, researchers at Johns Hopkins University have created a waterproof drone that can float up from the murky depths and then take to the skies to provide an aerial view. Named the CRACUNS (Corrosion Resistant Aerial Covert Unmanned Nautical System) the waterproof drone could be mounted to the outside of a submarine and only deployed as needed for additional intelligence gathering — without putting the billion dollar vessel at risk.
Built using custom 3D-printed parts, CRACUNS' electronic components are either protected inside waterproof housings, or like its four electric motors, treated with a cheap off-the-shelf coating that keeps H2O at bay. The approach helps keep the price of the drone affordable, so it could be treated as a disposable tool and deployed when situations were too risky for larger craft.
During testing the researchers at Johns Hopkins University's Applied Physics Lab left the CRACUNS submerged in salt water for as long as two months without affecting its ability to take flight whatsoever. Which means the drones could be secretly dropped from passing planes into coastal areas and left underwater for months before being deployed to fly inland to gather intelligence.