NASA has achieved a major milestone in its effort to build the nation's next heavy-lift launch vehicle by successfully completing the Space Launch System (SLS) preliminary design review.

Senior experts and engineers from across the agency concluded Wednesday the design, associated production and ground support plans for the SLS heavy-lift rocket are technically and programmatically capable of fulfilling the launch vehicle's mission objectives. NASA is developing the SLS and Orion spacecraft to provide an entirely new capability for human exploration beyond low-Earth orbit, with the flexibility to launch spacecraft for crew and cargo missions, including to an asteroid and Mars.

"The review had to be incredibly detailed, so our plans for vehicle integration, flight software, test, verification and operations will result in a safe, affordable and sustainable vehicle design," said Todd May, manager of the SLS Program at NASA's Marshall Space Flight Center in Huntsville, Ala.

This review concludes the initial design and technology development phase. The next milestone in the continuing verification process is Key Decision Point-C, in which NASA will grant the program authority to move from formulation to implementation.

"The agency not only reviews the program internally, but also seeks help from many external sources," said LeRoy Cain, head of the independent standing review board for SLS. "There are several external NASA stakeholders and organizations -- including Congress, the Office of Management and Budget, and the public -- who require a thorough, truly independent look at these programs as they transition through their lifecycle."

People from across the country, including experts on 11 different review teams, participated in the design review process, which included analysis of approximately 200 documents and 15 terabytes of data.

NASA's industry partners -- The Boeing Company of Chicago, ATK of Brigham City, Utah, and Aerojet Rocketdyne of Sacramento, Calif. -- also contributed to this successful checkpoint, and will continue to work to meet all program milestones.

In July 2012, the SLS Program completed a combined system requirements review and system definition review, which set requirements of the overall launch vehicle system. That successful completion confirmed the SLS was ready to move from concept to design. All element-level preliminary design reviews for the SLS core stage, boosters, engines and spacecraft and payload integration have been completed successfully.

"In two short years from the first announcement of the Space Launch System, we are at a milestone that validates the detailed design and integration of the system," said Dan Dumbacher, deputy associate administrator for the Human Exploration and Operations Mission Directorate. "You can feel the momentum of the workforce as we produce test hardware today. We are creating a national capability, and we will get this country, and the world, exploring deep space."

The initial 70-metric-ton version of SLS will stand 321 feet tall, provide 8.4 million pounds of thrust at liftoff, and carry 154,000 pounds of payload. The rocket is scheduled for its first mission, Exploration Mission 1, in 2017 at which time it will launch an uncrewed Orion spacecraft. The mission's goal is to demonstrate the integrated system performance of the SLS rocket and spacecraft before a crewed flight in 2021.

The SLS will be modified from the 70-metric-ton versionA into the most powerful rocket ever built, a 130-metric-ton version, which will be capable of lifting 286,000 pounds. NASA plans to engage industry peers to further refine the 130-metric-ton design to support any destination, any payload and any mission to deep space.

For more information on the SLS preliminary design review visit here