RLV is an acronym for Reusable Launch Vehicle. An RLV is a machine that puts people into space and then returns to earth where it can be refueled and launched again. Unlike ELVs and the space shuttle, RLVs can be completely reused.
Effective RLV designs are the key to cheap access to space, and will enable affordable space tourism. Current RLV designs include the NASA/Lockheed VentureStar and designs from Pioneer Rocketplane and Bristol Spaceplanes, as well as the Roton.