Sen— NASA has completed the preliminary design review of its deep space rocket called the Space Launch System (SLS).
The SLS is being designed to lift cargo and the Orion crewship beyond low-Earth orbit to destinations such as an asteroid and Mars.
The SLS moved from concept to design last year after completing a combined system requirements review and system definition review. The preliminary design review, which began in June, concluded that the rocket's design was capable of fulfilling the objectives for the SLS.
Todd May, manager of the SLS Program at NASA's Marshall Space Flight Center explained: "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."
The completion of the initial design phase means the next stage is what NASA calls "Key Decision Point-C" when officials decide whether to move the project to the next stage of development.
LeRoy Cain, head of the independent standing review board for the SLS, explained: "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."
If the SLS gets the official go ahead, its first test flight would take place in 2017. The 2017 mission, designated Exploration Mission 1, would see the SLS -- in its 70 metric ton configuration -- lift an unmanned Orion crew vehicle into space.
Orion meanwhile is scheduled to have an unmanned flight in 2014, to be launched by a United Launch Alliance Delta IV Heavy rocket rather than the SLS. Exploration Mission 1 would be the first pairing of the SLS and Orion.
The first manned flight of Orion and the SLS could come in 2021 when Exploration Mission-2 would see the SLS lift Orion carrying four astronauts into space.
The SLS, which will be certified for human spaceflight, is being designed with two configurations, one that can lift 70 metric tons and a larger configuration with a second stage that will be capable of lifting 130 metric tons.
In its larger format the SLS will stand 384 feet tall. Its height and lift capability will exceed those of the Saturn V moon rocket which stood 363 feet tall (110 metres) and could lift 120 metric tons to low-Earth orbit.
Since the retirement of the Space Shuttle in 2011 NASA has been without the capability to put cargo or crew into orbit, and relies on Russian Soyuz vehicles to ferry crew to and from the International Space Station.
NASA's strategy for low-Earth orbit missions is to outsource crew transportation to companies including SpaceX, Sierra Nevada Corporation and Boeing who are each developing a space vehicle designed to taxi astronauts to and from the space station. However, NASA hopes the SLS and its Orion spacecraft will provide the capability to explore space beyond low-Earth orbit.