The US space agency NASA is preparing for another attempt to launch its next-generation rocket to carry an unmanned spacecraft into orbit around the moon.

The launch was initially planned for Monday, but was postponed due to engine problems.

The 98-meter-high Space Launch System rocket is set to lift off from the Kennedy Space Center in Florida at 18:17 UTC on Saturday.

NASA says preparations for the launch are going smoothly.

NASA's new Orion space capsule is attached to the rocket and has three dummies inside. It will loop around the moon on a roughly 40-day test flight before returning to Earth.

Orion will collect data on impact and radiation necessary for future manned flights.

The rocket has been developed for the Artemis program, an international lunar exploration project aimed at sending astronauts to the lunar surface by 2025. It would be the first attempt since the Apollo program in the late 1960s and early 1970s.

Japan and some European countries are participants in the US-led program.