A massive structure described by NASA as the world’s largest spacecraft welding tool has been completed at the Michoud Assembly Center in New Orleans, which was chosen in 2011 to build components of a major new rocket system.

The 170-foot-tall, 78-foot-wide structure is called the Vertical Assembly Center. It will play a key role in construction of “Space Launch System” rockets.

NASA is designing the rockets to take astronauts beyond Earth orbit to an asteroid and eventually to Mars.

The Vertical Assembly Center will be used to build the “core stage” of the SLS rockets. The core stage will be more than 200 feet tall, with a diameter of more than 27 feet. Boeing is the prime contractor for the SLS core stage.