UNITED STATES: NASA gave the four Artemis astronauts circling Earth the green light on Thursday to head for the Moon and carry out the first crewed lunar flyby in more than 50 years.

NASA Flight Director Jeff Radigan told the astronauts the mission management team had approved firing up the engine of their Orion capsule to send the spacecraft on a trajectory towards the Moon.

The 5min and 49sec burn is scheduled to take place at 7:49 pm Eastern Time (2349 GMT) and send the astronauts out of Earth orbit to begin the three-day voyage toward the Moon, the first since 1972.

"Flight controllers will closely monitor engine performance, guidance, and navigation data throughout the maneuver to ensure Orion remains precisely aligned for the outbound journey," NASA said.

The enormous orange-and-white Space Launch System (SLS) rocket carrying the Orion capsule blasted off flawlessly from Kennedy Space Center in Florida on Wednesday for the long-anticipated journey around the Moon.

The astronauts -- Americans Reid Wiseman, Victor Glover and Christina Koch and Canadian Jeremy Hansen -- spent their first hours in space performing checks and troubleshooting minor problems -- including a communications issue and a malfunctioning toilet.

Before getting a few hours of sleep, they ignited the spacecraft's main engine to place it in a high Earth orbit, the US space agency said.

"Artemis II astronauts are doing great," NASA chief Jared Isaacman said in a post on X. "The Orion spacecraft is performing well in an impressive elliptical orbit."

Orion is to loop around the Moon as part of the 10-day Artemis 2 mission aimed at paving the way for a Moon landing in 2028.

Lunar mission

NASA gives Artemis crew green light to head towards Moon