The Ares I Crew Launch vehicle is currently being developed by NASA to launch the Orion Spacecraft. Together, along with the Ares V, the Ares I and Orion will replace the aging shuttle fleet. The first operational launch is scheduled for 2014, four years after the space shuttle is retired. The Ares I is the crew launch component of Project Constellation, the plan to send Americans back to the moon by 2020. Unlike with the space shuttle where both the crew and the cargo were launched in the same rocket, the crew and cargo will be launched separately. The unmanned Ares V will launch the cargo, while the Orion Spacecraft, launched atop the Ares I will take the role of carrying astronauts to the ISS and eventually the moon. The Ares I is based on the Space Shuttle Solid Rocket Booster. The first stage is an SRB with an added fifth segment to increase the lift capacity. The second stage features an Apollo program-derived J2X engine which will be used to blast the Orion out of earth orbit. The first stage will be recovered and reused in later missions, while the upper stage is expendable. Though the design has been heavily criticized, the Ares I holds promise for the future and will serve its mission well.