NASA is currently working on the Space Launch System (SLS) - the powerful rocket that is planned to be used for manned deep space missions to asteroids and eventually Mars.

Before any of those missions take place - and it will be a while, as astronauts are not expected to travel to an asteroid until the 2020s - the rocket has to be designed, built and tested. To build the core of the SLS, NASA has revealed the world's largest spacecraft welding tool. It's a sight to behold:

Image: NASA

The towering, 170-foot-tall 'Vertical Assembly Center' will join domes, rings and barrels to complete the tanks or dry structure assemblies, and also be used to evaluate the welds in detail.

Todd May, SLS program manager says "The SLS Programme continues to make significant progress. The core stage and boosters have both completed critical design review, and NASA recently approved the SLS Programme's progression from formulation to development. This is a major milestone for the program and proof the first new design for SLS is mature enough for production."

You can read more about the project here.