The private spacecraft carrying the UAE's Rashid rover will attempt a lunar landing today.
The Hakuto-R Mission 1 lander, built by ispace, will begin an hour-long landing sequence at 7.40pm GST. If all goes to plan it will slow down and descend towards the Moon before touching down softly on the surface.
If the landing is a success, the rover will then descend on to the surface, after nearly five months of being stored safely inside the Japanese spacecraft as it travelled to the Moon.
The UAE would then become the first Arab nation to have a spacecraft on the surface of another celestial body.
How to watch the lunar landing
Ispace will hold a gathering at the National Museum of Emerging Science and Innovation in Tokyo on Tuesday.
The event will be streamed live on ispace's YouTube channel, with scenes from mission control expected to be broadcast.
The broadcast will begin at 7pm.
What will the landing attempt entail?
The Hakuto-R M1 lander entered lunar orbit on March 21.
Since then, it has been getting closer to the surface through a series of manoeuvres.
On landing day, it will begin an hour-long landing sequence 100km above the surface.
Its main propulsion system will be fired in what is known as a braking burn, to help it decelerate from orbit.
Engineers have already programmed its commands, which means the lander will adjust its attitude (positioning in space) and reduce speed to make a soft landing.
Lunar landings are difficult because the Moon has no atmosphere, which means engineers cannot use parachutes to land spacecraft as they do on Mars and Earth.
Instead, complex manoeuvres are required to help the spacecraft decelerate so it touches down safely.
Only the US, China and the former Soviet Union have achieved soft landings. Israeli and Indian spacecraft crash-landed in 2019.
Where on the Moon is it landing?
Hakuto-R M1 will attempt a landing on the Atlas crater in the Mare Frigoris region of the Moon's near side, facing Earth. The co-ordinates will be 47.5°N, 44.4 E°.
Ispace says three alternative landing sites have been selected as a precaution.
If the first attempt is delayed, alternative landing dates are April 26, May 1 and May 3.
The Mare Frigoris region is also known as the Sea of Cold, as it is in the north polar region.
Scientists find the area particularly interesting because of the light plains scattered throughout the region.
Studying these will help scientists learn more about the geological history of the unexplored region.
What happens after landing?
If the spacecraft lands softly, Emirati engineers will carry out health and safety checks on the Rashid rover before it is lowered on to the surface.
It will then spend 14 days exploring the area, during which it will record and send data on the Moon's geology and dust.
Engineers hope to take more than 1,000 images of the surface and its surroundings.
The Mohammed bin Rashid Space Centre is already working on a second lunar rover.