[Reading Science] The 'God's Move' Behind Making Two More Danuri Spacecraft

Earlier this year, Korea's first lunar exploration orbiter, Danuri (KPLO), which began its official mission, recently brought joyful news. Its mission period (1 year) has been extended by a full 2 years. Danuri was developed and launched at a cost of about 200 billion KRW. Simply put, this extension has earned the equivalent of over 400 billion KRW, enough to produce two more Danuri spacecraft.

What was the “masterstroke” that effectively created “two more” Danuris? First, cooperation with NASA played a crucial role. The Korea Aerospace Research Institute (KARI) signed an agreement with NASA in 2016 and has collaborated throughout Danuri’s development, launch, and operation. NASA transferred deep space navigation and communication technologies, which Korea had no prior experience with. In return, KARI equipped Danuri with NASA’s ShadowCam, designed to capture permanently shadowed regions. This helps select landing sites for Artemis, humanity’s second lunar landing project.

The most decisive factor in this process was adopting the ballistic lunar transfer (BLT) orbit based on NASA’s advice. Initially, KARI chose a phasing orbit method, which involves orbiting Earth and then gently entering lunar orbit?a method commonly used by other beginner countries lacking experience and know-how. However, in 2018, they faced a major challenge. The originally designed weight of Danuri was 550 kg, but after adding all components, it turned out to be 675 kg?23% heavier. This was because, as a first deep space probe, it was built prioritizing stability and high performance. The fuel was limited to 260 kg, but the spacecraft’s weight had significantly increased. This made the originally planned stable 1-year mission impossible. At this point, KARI received a proposal from NASA to use the BLT method. Although NASA had only tested this technology, they advised that by utilizing Earth’s and Moon’s gravity, fuel could be conserved to successfully complete the mission. This also became an opportunity for Korea to gain recognition for its capabilities through its first space development cooperation with NASA.

The second factor was what Korea’s own engineers accomplished. KARI engineers completed the nine planned trajectory correction maneuvers (TCMs) in just five. They also reduced the planned five lunar orbit insertion (LOI) maneuvers to three. This was a miracle achieved by “novice” operators conducting deep space navigation for the first time. According to Kim Dae-gwan, the lead researcher overseeing the Danuri project, luck, skill, and effort all played a role. The favorable angle at separation from SpaceX’s Falcon 9 was luck. However, decades of experience in satellite manufacturing contributed skillfully. The thrusters’ performance and mounting angles were excellent. Effort was also key. KARI engineers meticulously designed trajectories down to nine decimal places to avoid rookie mistakes. They worked overnight without hesitation, finely adjusting thrust during each maneuver to control Danuri with neither excess nor deficiency.

The lesson from this Danuri mission extension is clear. For future mega- and micro-scale scientific research projects that will determine humanity’s fate, international cooperation is essential. This is especially true in fields where Korea is still far behind. The multidisciplinary and convergent research, as well as cooperation among industry, academia, and research institutes that produced the “first-ever” lunar probe Danuri, along with the utilization and development of Korea’s industrial base, are equally important. To open the era of lunar exploration and space economy, and to pioneer humanity’s future against climate change, resource depletion, and environmental pollution, the Republic of Korea must learn from Danuri’s success.

This content was produced with the assistance of AI translation services.