The Korea AeroSpace Administration said on 24th that Danuri, the lunar orbiter carrying out an extended mission, will complete its low-altitude mission, enter a frozen orbit that can be maintained without additional fuel consumption, and carry out additional tasks.
Danuri, launched on Aug. 5, 2022, lowered its mission operation altitude from 100 kilometers to 60 kilometers on Feb. 19 and carried out a low-altitude mission for about seven months. The frozen orbit that it will now enter for the additional mission is an elliptical orbit that is naturally maintained without fuel consumption for orbital adjustments due to the moon's gravity distribution characteristics. Danuri is scheduled to be placed in a frozen orbit with a low altitude of 60 kilometers and a high altitude of 200 kilometers.
During the mission operation period under frozen-orbit conditions, the mission will use the characteristics of the elliptical orbit to conduct additional scientific observations, including improving the resolution and clarity of lunar surface images, observing changes in shadow conditions in the permanently shadowed regions of the lunar north and south poles, and measuring magnetic fields at various altitudes.
However, because Danuri is operating beyond its design life, the performance of its battery and solar cells has declined, requiring caution in mission operations. Earlier, during two total lunar eclipses on Mar. 14 and Sept. 7, Danuri maximized battery charging in advance and minimized power consumption to prepare for potential power shortages. After the frozen-orbit mission ends in 2027, the plan is to perform a disposal maneuver to secure landing data needed for a lander mission, then collide with the lunar surface to formally end the mission.
Kang Kyung-in, head of space science exploration at the Korea AeroSpace Administration, said, "Danuri has achieved additional scientific results, such as acquiring high-resolution images through the extended low-altitude mission, and it is expected to make a significant contribution to the advancement of lunar science by obtaining observation data from various lunar orbits through long-term observations in the future in the elliptical frozen orbit."