The almost zodiac-like craft has been an ongoing project over recent years, and contains a fully automated system which the Navy calls a "Precision Engagement Module" which uses an Mk-49 mounting with a dual missile launcher manufactured by Rafael.

ENGADGET: US Navy tests first 11-meter missile-firing sea drone (video)

The craft is carrying a time capsule in the form of a golden gramophone record, complete with stylus, which contains a recording of greetings from Earth in different languages as well as samples of music ranging from Mozart to singer Blind Willie Johnson.

BBC: Voyager impression (Nasa)