NASA's giant US moon rocket emerges for debut launch

 NASA's gigantic Space Launch System moon rocket, topped with an uncrewed astronaut capsule, began an hours-long crawl to its launchpad Tuesday night (Aug 16) ahead of the behemoth's debut test flight this month.

The 98m-tall rocket is scheduled to embark on its first mission to space - without any humans - on Aug 29. It will be a crucial, long-delayed demonstration trip to the moon in NASA's Artemis programme, the United States' multibillion-dollar effort to return humans to the lunar surface as practice for future missions to Mars.

The Space Launch System, whose development during the past decade has been led by Boeing Co, emerged from its assembly building at NASA's Kennedy Space Center in Florida about 10pm EDT on Tuesday (Wednesday, 10am, Singapore time) and began a 6km trek to its launchpad.

Moving less than 1.6kmh, the rollout takes roughly 11 hours.

Sitting atop the rocket is NASA's Orion astronaut capsule, a pod built by Lockheed Martin Corp. It is designed to separate from the rocket in space, ferry humans toward the moon's vicinity and rendezvous with a separate spacecraft that will take astronauts down to the lunar surface.

But for the Aug 29 mission, called Artemis 1, the Orion capsule will launch atop the Space Launch System without any humans and orbit around the moon before returning to Earth for an ocean splashdown 42 days later.

If bad launch weather or a minor technical issue triggers a delay from Aug 29, the National Aeronautics and Space Administration has backup launch dates on Sep 2 and Sep 5.