The Ares V (formerly known as the Cargo Launch Vehicle or CaLV) was the planned cargo launch component of the cancelled NASA 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. The Ares V was to launch the Earth Departure Stage and Altair lunar lander for NASA's return to the Moon, which was planned for 2019. It would also have served as the principal launcher for missions beyond the Earth-Moon system, including the program's ultimate goal, a crewed mission to Mars. The uncrewed 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 then-current Space Shuttle, would have employed technologies developed for the Apollo program, the Shuttle program, and the Delta IV EELV program. However, the Constellation program, including Ares V and Ares I, was canceled in October 2010 by the NASA Authorization Act of 2010. In September 2011, NASA detailed the Space Launch System as its new vehicle for human exploration beyond Earth's orbit, while commercial space companies would provide low earth orbit access for both cargo and astronauts. Development Early concepts In the 1996 book The Case for Mars, author Robert Zubrin discussed a possible future heavy launch vehicle named Ares. In the book, the rocket would have consisted of the Space Shuttle external tank powered by four Space Shuttle Main Engines (SSMEs) and a second stage powered by an RL-10 engine. One notable difference in the Zubrin et al. design is that the SSMEs were on a small side-mounted flyback craft. This design was meant to allow the Ares to fly using existing Space Shuttle infrastructure. Constellation Ares V was to be the cargo launch component of the Constellation program. Unlike the Saturn V and Space Shuttle, where the crew and cargo were launched together on the same rocket, Project Constellation planned to use two separate launch vehicles, the Ares I and the Ares V, for crew and cargo respectively. This configuration would have allowed the two launch vehicles to be optimized for their respective missions. Constellation therefore combined the Lunar Orbit Rendezvous used by Apollo with the Earth Orbit Rendezvous mode proposed by Dr.