The design for NASA's future monster rocket — dubbed the Space Launch System (SLS) — passed its last critical design review. That means NASA found that the vehicle’s specifications hold up, and the agency has deemed the design capable of launching into space. Now, engineers can begin the process of building and assembling the rocket, to get ready for its next major review in 2017. That test will determine how well the manufactured rocket matches up to its original design.

Along with passing the design review, the SLS also got an upgraded look this week. A new artist’s rendering of the vehicle shows most of the rocket's fuselage painted a burnt orange with a few grey streaks on its solid rocket boosters. The coloring is new, and the burnt orange hues inspire a hint of nostalgia, making the rocket reminiscent of NASA's canceled Space Shuttle, which traveled into space on the back of a giant burnt orange fuel tank. An ironic choice, as the SLS is often considered the replacement for the grounded Shuttle.

NASA hopes to use the SLS to transport astronauts beyond lower Earth orbit into deep space. The idea is for the vehicle to take humans near the Moon in 2020, and then to the surface of Mars in the 2030s. Up to four people will ride in the SLS inside NASA's Orion crew vehicle, which is designed to sit on top of the rocket in its upper stage. The Orion spacecraft is currently under development at NASA and underwent its own critical design review in August. The space agency has successfully shown that test versions of the Orion can land safely from both space and high altitudes, even when two of its main parachutes fail.

Although a test version of the SLS hasn't been built yet, NASA engineers have conducted numerous ignition tests on the main RS-25 engines that the vehicle will use. The SLS will have four of these engines, along with two solid rocket boosters attached to the main rocket to provide additional thrust during launch. Eventually, NASA plans to build two updated versions of the rocket, which will use bigger upper stages, along with more advanced rocket boosters. However, these alternative forms of the SLS have yet to pass a critical design review.

Despite passing this major test, the SLS program has run into a few setbacks recently. Last month, the first crewed flight of both SLS and Orion was tentatively pushed back by two years; originally scheduled for August 2021, it's looking more likely the flight, titled EM-2, will happen in April 2023. NASA said it pushed back the dates due based on how much money the Orion program is scheduled to receive based on the president's proposed budget.