“This very ground you’re standing on is the launch pad. At around 7:30 a.m. today, the launch vehicle, which had completed final assembly at the assembly building, was transported 1.8 km to the launch pad. After over an hour of work, it was erected as you see it now.”
At 4 p.m. on the 16th at the Naro Space Center launch pad in Goheung, South Jeolla Province, Kim Dae-rae, director of the Korea Aerospace Research Institute’s Naro Space Center, pointed to the Nuri rocket standing upright on the Vehicle Holding Device (VHD).
A green steel structure stands alongside the launch pad where the rocket is positioned. It is the umbilical tower, meaning “umbilical cord.” It supplies propellant to the erected launch vehicle. Director Kim explained, “If the Nuri flight model is a baby, the umbilical tower is its mother. The umbilical tower provides the best environment for the baby to reach space.”
South Korea’s domestically developed space launch vehicle Nuri has entered the final inspection phase ahead of its fourth launch in November. On this day, the Ministry of Science and ICT and the Korea Aerospace Research Institute (KARI) conducted a Wet Dress Rehearsal (WDR), a procedure that simulates the final countdown before launch.
The term WDR is borrowed from theater. It is similar to a final rehearsal where lighting, costumes, and sound are tested as if it were the actual performance. The same applies to rockets. During the WDR, the actual flight model is filled with liquid propellant and tested up to the stage just before engine ignition. Hence, the term “wet” is used, and it is called WDR. Director Kim stated, “After analyzing the data obtained from today’s WDR, the final launch date will be determined at the Launch Management Committee meeting on the 26th.” The ministry expects the launch to occur around late November, with the launch window set between 12:54 a.m. and 1:14 a.m.
◇Nuri Prepares to Return to Space After a Two-and-a-Half-Year Hiatus
Nuri made history with its first successful flight in 2021 as South Korea’s first domestically developed space launch vehicle. In May 2023, it successfully completed its third launch using technology co-developed by the government and private sector, proving that South Korea could launch satellites into space with its own technology. For this fourth launch, Hanwha Aerospace, a private company, will participate in all processes from manufacturing to launch. This marks the first space launch led by the private sector.
Tension filled the Naro Space Center ahead of the fourth launch. This is not only the first private-led launch operation but also follows a two-and-a-half-year hiatus since the third launch. The decision to conduct the WDR, which was not performed during the second and third launches, stems from this context.
Typically, flight models (FM) are used sparingly during rocket development. Since components and systems are already verified, and qualification models (QM) undergo comprehensive combustion tests and assembly procedures, flight models are usually launched directly. WDRs are conducted only during the first development launch or when a fixed launch date must be strictly adhered to.
Park Jong-chan, head of the Korea Space Launch Vehicle Advancement Project Team, said, “We are conducting the WDR with the mindset of checking even the sturdiest bridge before crossing it.” The goal is to minimize the risk of failure on launch day by addressing potential issues on the ground.
◇South Korea’s First Private-Led Space Launch
This fourth Nuri launch is historically significant as the first in South Korea’s space industry to be led by a private company. Hanwha Aerospace, as the system integrator, is leading the entire process from design to launch operations. To this end, KARI transferred a total of 16,050 technical documents to Hanwha Aerospace. While the company participated only in partial stage assembly during the third launch, this time it is overseeing the entire process, including managing subcontractors, stage assembly, and full vehicle assembly.
Senior Researcher Kim Ji-nam of Hanwha Aerospace said, “We are proceeding with the launch while receiving technology transfers from KARI. All component and vehicle inspections have been completed, and the work is progressing smoothly so far.”
Starting from the sixth launch, Hanwha Aerospace will also assemble the launch vehicle at a stage assembly facility under construction in Suncheon.
◇Domestic Hydrazine Fuel Charging Facility for Satellites
On one side of the Naro Space Center stands South Korea’s first hydrazine charging and containment facility. Hydrazine is the fuel for the Next-generation Medium Satellite 3, the main satellite to be launched on this mission. It is used for orbit correction and attitude control. Since fuel cannot be preloaded during satellite production, a charging facility must be established at the launch site.
While hydrazine is an efficient fuel, it is highly toxic. Therefore, the facility must include leak detection sensors and decontamination systems. HD Hyundai Heavy Industries completed the construction, and U.S. company UPC, a specialist in hydrazine handling, verified the facility’s stability. After the satellite’s transfer and inspection are completed by the end of October, the plan is to charge the fuel before the fourth launch.
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