Once complete, the SLS will be the most powerful launch vehicle ever constructed, capable of taking humans to hitherto unreachable destinations including a manned mission Mars.

The review took 11 weeks, and saw 13 teams of NASA engineers and scientists review over 1,000 documents in order to determine whether the gargantuan rocket concept was ready to transition into full-scale production. The design review has now been submitted to a Standing Review Board composed of experts independent of the program.

The next step will be to present the results of the board to the Marshall's Center Management Council, and then the Human Exploration and Operations Mission Directorate at NASA Headquarters.

The 2015 critical design review is only effective for the first of three planned SLS variations. The first iteration is known as Block 1, which will stand an impressive 322 ft (98 m) tall and boast four RS-25 engines similar to those used in the shuttle program, along with two side mounted 177 ft (54 m) long solid fuel boosters.