Nasa has started assembling the first Space Launch System (SLS) rocket on a launch platform ahead of its maiden flight next year.

The SLS is the giant rocket that will send US astronauts back to the Moon this decade - with the first crewed landing targeted for 2024.

Engineers in Florida have begun stacking the segments that make up the vehicle's two solid rocket boosters.

The rocket is scheduled to make its debut in November 2021.

The SLS consists of a giant, 65m (212ft) - long core stage with four engines that's flanked by the twin solid fuel boosters.

The boosters will burn six tonnes of solid, aluminium-based propellant each second when the SLS launches.

The mobile launcher they're being stacked on is a 115m (380ft) -tall structure that's used to process and assemble the SLS before moving it to the launch pad.

Once it's fully assembled, the SLS rocket will stand taller than the Statue of Liberty and have about 15% more maximum thrust at lift-off than the Saturn V rocket used to launch the Apollo missions to the Moon in the 1960s and 70s.

The booster segments being assembled in Florida will launch Nasa's next-generation astronaut vehicle, Orion, on a loop around the Moon in November next year.

It will be used to check out the vehicle's performance before humans are allowed onboard for the Artemis-2 mission, currently scheduled for 2023.