The two contractors chosen, Northrop Grumman Systems Corporation and Martin Defense Group, will each build and showcase a full-size demonstration drone. The mission profile here presents an impressive challenge; these machines must be incredibly self-sufficient in a harsh environment.
They must be able to stop and charge their batteries, presumably harvesting power from underwater currents. They will need to be able to sense, label and avoid all sorts of obstacles to avoid getting trapped in algae, scratched by rocks and coral or stuck in crevasses and they will also need to be highly corrosion resistant to cope with the salt sea's ability to devour metal. and capable of dealing with the wide range of microorganisms and macroorganisms that will attempt to take up residence on the drone's surfaces.
And while doing all this, they will need to be able to self-navigate, communicate with the surface and transport significant mission payloads for potentially months and months, presumably while being very difficult to detect.