So why does it take so long for Danuri to reach the moon?
One of Danuri's key features is that it uses gravity to propel the orbiter toward its destination.
Though this feature greatly extends travel time to moon, it helps saves fuel, which is crucial factor in fulfilling its mission.
KIM Jung-sil reports.
Normally, it takes as little as 3 days to get to the moon, but Danuri is looking at a journey of about four and a half months.
It's because the orbiter will use a more energy-efficient method of travel.
"The trajectory used for Danuri is called the "Ballistic Lunar Transfer", BLT is an energy-efficient one."
This BLT method is the key to Danuri's successful lunar mission.
And it's so difficult that no other countries, apart from the U.S., and Japan have attempted it.
The route will take Danuri, first, some 1.56 million kilometers in the direction of the sun before it loops back around the earth to enter a trajectory toward the moon around December 16th.
This way, Danuri can make fuel savings of 20-25%, a precious amount in the depths of space.
Scientists at the Korea Aerospace Research Institute originally designed Danuri to make three and a half rotations of the earth for a shorter trip.
But as Danuri was being built, it became much heavier than planned.
If Danuri had reached the moon with no fuel, it wouldn't have been able to conduct any of its mission.
So, officials chose to use gravity to propel the orbiter instead.
On its journey, Danuri will draw a giant ribbon-like figure and fly about 6 million kilometers.
That's about 15 times the distance between the moon and earth which is about 380,000kilometers.
Danuri will begin to slow down from December 16th before entering its target orbit 100 kilometers above the moon's surface.
Authorities expect that at least 9 trajectory adjustments will need to be made before its mission begins.
KIM Jung-sil, Arirang News.