NASA announced on 30-June-2006 the names of the next generation of launch vehicles that will return humans to the moon and later take them to Mars and other destinations. The Crew Launch Vehicle (CLV) will be called Ares I, and the Cargo Launch Vehicle (CaLV) will be known as Ares V.
Since the original CLV and CaLV plans were announced in 2005, several design modifications have been made to both launch vehicles.

Ares I (CLV):
• Stage 1 has been upgraded from a 4-segment RSRM to a 5-segment RSRM.
• Stage 2 engine has been changed from a single SSME to one Rocketdyne J-2X engine.

Ares V (CaLV):
• Booster  has been upgraded from a 5-segment RSRM to a 5.5-segment RSRM.

• Stage 1   engines have been changed from five SSME to six Rocketdyne RS-68 engines.
                  diameter has been increased from 8.4 m to 10.0 m to accomodate greater propellant load.
• Stage 2   engine has been changed from two Rocketdyne J-2S to one Rocketdyne J-2X engine.
                  diameter has been increased from 8.4 m to 10.0 m to accomodate greater propellant load.

Ares V will use five RS-68 liquid oxygen/liquid hydrogen engines on a 10-meter diameter core with two five-segment RSRMs for the first stage. The upper, "Earth Departure" stage will also be powered by a single J-2X engine. Ares V will stand more than 109 meters tall, will weigh 3,356 tonnes at liftoff, and will be able to lift about 130 tonnes to low Earth orbit.

An early change increased the diameter of the upper stage and payload shroud to 10 meters, matching the core diameter. Additional changes included increased RSRM nozzle length, changes to the solid propellant mix, improved RSRM vacuum specific impulse, bettered RS-68 thrust and specific impulse, and increased use of lighter weight composite structures.

On June 23, 2008, NASA announced that the Ares V baseline design had grown larger and more powerful than previous designs. The trans-lunar insertion (TLI) capability had risen to 71 tonnes, a 7 tonne increase. The theoretical Low Earth Orbit (LEO) payload had grown to 145 tonnes or more from the previous 130 tonnes.
Planners added a sixth RS-68 engine to the core stage and specified a pair of five-and-a-half segment solid rocket boosters. The previous design used five RS-68s and two five-segment boosters. The core stage was lengthened. The Earth Departure Stage (EDS) diameter had already been increased to 10 meters to match the core diameter during recent design iterations. The payload fairing diameter also grew to 10 meters. Overall height jumped to 116.16 meters, 5.56 meters taller than Saturn V. Lift-off weight increased to 3,699.23 tonnes and lift-off thrust to an unprecedented 5,306 tonnes.