Leviathan

The many variants of the Leviathan are the work horse of interplanetary civilization. Almost all launches of bulk cargo from habitable planets have been done with this type of rockets, since it replaced its predecessor, the Sea Dragon, in the mid 21st century. Leviathan is the pinnacle of the Big Dumb Booster paradigm of rocket engineering: Instead of smaller and more efficient, but complicated designs, enormous, simple rockets are build. Leviathan is capable of lifting over a thousand tons of cargo into a low orbit in a single launch.
The rockets are constructed from simple materials such as steel sheeting in factories on the shore. In the early days, these were retrofitted naval dockyards. They are then towed out to sea, where their tanks are filled by ships. Attached to the first stage engine cone is a ballast tank which is filled with water, pulling the rocket upright. It is then launched from the water. The first stage splashes down several hundred kilometers downrange. Thanks to the simple construction it can be refurbished, making Leviathan partially reusable.

by Graphic by AstroBidules - Own work, CC BY 4.0