'Prüfstand XII' was a German programme to develop an encapsulated version of the V-2 ballistic missile which could be towed across the Atlantic Ocean by a U-boat for launch against a target on the east coast of the USA (1943/45).

The concept was based on the idea that the capsule, once towed across the Atlantic, would be elevated to the vertical position by the flooding of its lower end, after which the hatch in the upper end would be opened and the missile launched. The first three capsules were under construction at the time of Germany’s surrender in May 1945.