Floating launch vehicle operations platform

A floating launch vehicle operations platform is a marine vessel used for launch or landing operations of an orbital launch vehicle by a launch service provider: putting satellites into orbit around Earth or another celestial body, or recovering first-stage boosters from orbital-class flights by making a propulsive landing on the platform. In the early decades of spaceflight technology, all orbital launch vehicle operations were exclusively from land, and all booster stages were expended after a single use for nearly 60 years after the first orbital spaceflight, Sputnik 1.

Source: Wikipedia — Floating launch vehicle operations platform (CC BY-SA 4.0)