A 170-foot powerhouse -- the Vertical Assembly Center (VAC) -- is near completion and will soon be ready to build the core stage of NASA's Space Launch System (SLS). SLS will be the most powerful rocket in history for deep space missions, including to an asteroid and ultimately to Mars.

This photo taken with a special camera lens shows the VAC, the world's largest spacecraft welding tool -- part of a family of tools at NASA's Michoud Assembly Facility in New Orleans.

These tools are specifically designed to build the core stage, which will store cryogenic liquid hydrogen and liquid oxygen that will feed the vehicle's RS-25 engines.

The core stage is comprised of five major structures: the forward skirt, the liquid oxygen tank, the intertank, the liquid hydrogen tank and the engine section.

The core stage recently passed its critical design review -- a major milestone for the program which proves the first new design for America's next great rocket is mature enough for production. Boeing is the prime contractor for the SLS core stage, including avionics.

The first flight test of the SLS will feature a configuration for a 70-metric-ton (77-ton) lift capacity and carry an uncrewed Orion spacecraft beyond low-Earth orbit to test the performance of the integrated system.

As the SLS evolves, it will provide an unprecedented lift capability of 130 metric tons (143 tons) to enable missions even farther into our solar system to places like Mars.