The three-day Lunar Capability Concept Review capped a nine-month study led by the Exploration Systems Mission Directorate at NASA Headquarters in Washington that incorporated science and exploration objectives earlier developed by representatives of 14 countries. The study is part of NASA's Constellation Program, which has the responsibility for developing the next human space transportation system that will be used to extend a human presence throughout the solar system.

The Lunar Capability study looked at possible lunar mission scenarios and compared them to the capabilities of the emerging Ares V heavy lift launch vehicle and the Altair lunar lander design concepts.

"We confirmed that Constellation's conceptual designs for both Ares V and Altair will enable us to land astronauts and cargo anywhere on the moon and to build an outpost supporting widespread exploration of the lunar surface," said Jeff Hanley, Constellation Program manager.

According to Hanley, the study bears out the strength of the initial concepts showing the vehicles can be built and delivered in time to return humans to the moon by 2020.

The review refined early configurations of the Ares V rocket to ensure its capability to deliver the Altair lunar lander, four astronauts and cargo anywhere on the moon and return the crew to Earth at any time. To accomplish those objectives, the current configuration of the Ares V will use six RS-68B liquid oxygen and liquid hydrogen engines on a core stage along with two five-and-one-half segment solid propellant rocket boosters, which are a direct evolution from the first stage of the Ares I rocket. The Ares V upper stage will propel the Orion crew capsule and Altair to the moon using the same J-2X engine as the Ares I crew launch vehicle. The Ares V will stand about 381 feet tall and be able to send more than 156,600 pounds of cargo and components into orbit to the moon, and later to Mars or other destinations.

Altair will be capable of landing four astronauts anywhere on the moon, providing life support and a base for the first week-long surface exploration missions, and returning the crew to the Orion spacecraft for the ride home to Earth. A variant of the lunar lander will serve as an autonomous cargo carrier, taking modular outpost components, lunar rovers, and scientific equipment to the moon's surface.

The formal decision to start Phase A will be taken to NASA's leaders before the end of this year.