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 was also planned to carry supplies for a human presence on Mars. 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 and Ares I was canceled in October 2010 by the passage of the 2010 NASA authorization bill. In September 2011 NASA detailed the Space Launch System as its new vehicle for human exploration beyond Earth's orbit.

For the Zodiac sign, see Aries (astrology).

Ares (Ancient Greek: Ἄρης [árɛːs], Μodern Greek: Άρης [ˈaris]) was the Greek god of war. He is one of the Twelve Olympians, and the son of Zeus and Hera. In Greek literature, he often represents the physical or violent aspect of war, in contrast to the armored Athena, whose functions as a goddess of intelligence include military strategy and generalship.

The Greeks were ambivalent toward Ares: although he embodied the physical valor necessary for success in war, he was a dangerous force, "overwhelming, insatiable in battle, destructive, and man-slaughtering." Fear (Phobos) and Terror (Deimos) were yoked to his battle chariot. In the Iliad his father Zeus tells him that he is the god most hateful to him. An association with Ares endows places and objects with a savage, dangerous, or militarized quality. His value as a war god is even placed in doubt: during the Trojan War, Ares was on the losing side, while Athena, often depicted in Greek art as holding Nike (Victory) in her hand, favored the triumphant Greeks.