The Ares V (formerly known as the Cargo Launch Vehicle or CaLV) was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V and the smaller Ares I were named after Ares, the Greek god of war, which is the equivalent to the Roman god Mars.

Initially, the Ares V would have launched the Earth Departure Stage and Altair lunar lander had NASA returned to the Moon, which was planned for 2019, but would also have served as the principal launcher for missions beyond the Earth-Moon system, including the program's ultimate goal, a manned mission to Mars after 2030. The unmanned Ares V would complement the smaller, and human-rated Ares I rocket for the launching of the 4-6 person Orion spacecraft. Both rockets, deemed safer than the current Space Shuttle, would have utilized technologies developed for the Apollo program, the Shuttle, and the Delta IV EELV programs. However, the Constellation program, including Ares V was canceled in October 2010 by the passage of the 2010 NASA authorization bill.