HUNTSVILLE, Ala. - NASA has completed the Ares I crew launch vehicle system requirements review -- the first such milestone for a U.S. human-rated launch vehicle system in more than 30 years. This review brings the agency one step closer to developing a new mode of space transportation for astronauts on missions to explore the moon, Mars and other destinations.

"This is a critical step for development of the Ares I crew launch vehicle," said Constellation Program manager Jeff Hanley. "A great deal of engineering analysis and planning has culminated in a thorough review that gives us confidence to go forward with Ares I design work."

The system requirements review confirmed that the Ares I system requirements were complete, validated and responsive to mission requirements.

It also confirmed that the Ares I architecture and design concept can fulfill the mission objectives and that the Ares project is ready to begin engineering design activities. The Ares preliminary design review is scheduled for mid-2008.

This review is the first in a series of milestones that will occur before the actual flight hardware is built. Each major review provides more detailed requirements for the vehicle design to ensure the overall system can meet all NASA requirements for safe and reliable flight. The review process also identifies technical and management challenges, and addresses ways to reduce potential risks as the project goes forward.

"The successful completion of this first review is the culmination of a lot of hard work and long hours by many people around the country by our government and industry team," said Steve Cook, manager of Marshall's Exploration Launch Projects Office. "The result of their tireless efforts is that the board confirmed that we have a good, stable set of requirements to start the design phase of Ares I."

Among the items addressed in the review was the commitment to reduce operations costs through streamlined launch vehicle processing. All hardware elements -- the first stage, upper stage and upper stage engine -- are emphasizing operations simplicity to enable NASA to sustain long-term exploration of space within its budget.

The review follows a series of successful system requirements reviews for the Ares launch vehicle project, including for the J-2X engine, Ares I first stage and Ares I-1 test flight. The J-2X engine will power the upper stage of Ares I, as well as the Ares V Earth departure stage that will propel Orion from Earth orbit to the moon late next decade. Ares I-1, planned for launch in 2009, will be the first test flight of the integrated launch vehicle system.

In January 2007, the Ares project will begin the second in a series of design analyses cycles leading to final design and fabrication of the launch vehicle. This cycle will baseline design changes made during the first cycle. In the updated Ares 1 configuration, a common bulkhead between the upper stage liquid hydrogen and liquid oxygen tanks has been substituted for an intertank, thus shortening the vehicle. The thrust profile for the Ares I first stage also has been baselined. This means requirements have been established for how the solid propellant inside the five-segment reusable solid rocket booster burns during ascent.

The Constellation Program, located at NASA's Johnson Space Center in Houston, has overall responsibility for development of the crew exploration and launch vehicles and related systems in support of NASA exploration missions to extend a human presence throughout the solar system. The Exploration Launch Projects Office at NASA's Marshall Space Flight Center in Huntsville, Ala., is responsible for design and development of the Ares I crew and Ares V cargo launch vehicles. Johnson is responsible for development of the Orion capsule and mission operations. NASA's Kennedy Space Center in Florida is responsible for ground and launch operations. The program also includes multiple project element teams at NASA centers and contract organizations around the nation.