NASA/Michoud / Wikimedia

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

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

NASA's Michoud Assembly Facility in eastern New Orleans is closed for until Tropical Storm Isaac passes.

Plant officials said employees should monitor the facility's website, www.mafspace.msfc.nasa.gov/status/index.html or call 800-611-3116 for notice of the facility‚ÄČs reopening plan.