COVER STORY Nuri rocket successfully completes 5th flight

Korea’s home-developed Nuri rocket successfully carried out its mission in its fifth launch Wednesday, sequentially deploying 14 out of 15 satellites it carried into their target orbit.

The key objective of the fifth launch was to safely deploy the five microsatellite constellations, and the success has demonstrated Korea's increased multi-satellite launch capabilities, taking another step toward privately led commercial launch services.

The rocket lifted off from the launchpad at the Naro Space Center in Goheung, Jeonnam-Gwangju Special Metropolitan City, at 12:25 p.m. and completed its roughly 20-minute flight at around 12:45 p.m.

The rocket separated its first stage about two minutes after liftoff, followed by the second stage about four and a half minutes into the flight. At around 12:40 p.m., it reached an altitude of 570 kilometers and completed the sequential deployment of five New-space Earth Observation Satellite Constellation for National Safety (NEONSAT) microsatellites (satellites No. 2 to 6), its primary payload, along with nine of the 10 CubeSats it carried.

Initially, the Nuri sent signals indicating that all of the CubeSats had been successfully deployed. However, subsequent checks found that PERSAT02, developed by Quaternion, had failed to separate from the rocket.

"The Nuri rocket successfully completed its planned fifth launch mission,” Korea AeroSpace Administration (KASA) Administrator Oh Tae-seog said during a press briefing at around 2 p.m.

“The five NEONSAT microsatellites, the primary payload, were also confirmed to have separated successfully according to the planned sequence. NEONSAT No. 6 successfully established its first communication with the King Sejong Station in Antarctica at around 1:08 p.m., and the others are expected to establish communications sequentially.”

The Nuri carried 15 satellites on its fifth launch, the largest number ever carried by the rocket, up from 13 on the fourth launch, which carried the third next-generation medium-sized satellite and 12 CubeSats. The total payload weight also increased to about 1,071 kilograms from roughly 960 kilograms.

The Nuri rocket deployed the satellites at an altitude of 570 kilometers, 30 kilometers lower than on the fourth launch, to meet the orbital requirements of the NEONSAT mission.

The satellite deployment sequence was also more challenging than during the fourth launch. In the previous mission, one primary satellite was separated and followed by pairs of secondary satellites at intervals of about 20 seconds.

This time, the rocket began separating the five primary NEONSATs about 810 seconds after liftoff at intervals of 35 to 40 seconds, while pairs of secondary satellites were deployed at intervals of about 10 seconds, except for the one that failed.

The Nuri successfully performed collision avoidance maneuvers between satellite separations, demonstrating its capability to deploy multiple satellites into a single orbit.

“With the success of the fifth launch, the Nuri’s cumulative launch success rate rose from 75 percent to 80 percent, further improving the rocket’s reliability,” Oh said.

“The fifth launch is also significant because it successfully demonstrated the precise deployment of multiple satellites in a single launch. This was the first time Korea deployed five primary satellites into space simultaneously. The successful deployment of the satellite constellation demonstrated a more advanced space transportation capability that can support diverse missions according to customers’ desired orbits and schedules."

The Korea Advanced Institute of Science & Technology (KAIST) oversaw the development of the five NEONSAT satellites. Each is an Earth observation satellite weighing less than 100 kilograms, designed to capture high-resolution images with a ground resolution of 1 meter in black and white and 4 meters in color.

Five additional satellites are scheduled to launch aboard Nuri on its sixth mission in 2027. Once the constellation of 10 mass-produced satellites is operational, it will be able to image the Korean Peninsula at least three times a day and revisit the same location within 24 hours in emergencies.

The CubeSats included a range of missions designed to test technologies developed by private companies in the space environment. SpaceLiinTech’s BEE-1012 will conduct an experiment to grow pharmaceutical crystals in microgravity, with onboard artificial intelligence analyzing their formation and growth and adjusting the experiment.

UEL-Y-Sys, developed by Unmanned Exploration Laboratory, will test LG Group’s electronic equipment and cameras for potential use in lunar exploration. Korea Aerospace Research Institute’s CubeSat carries SK hynix DRAM and universal flash storage memory to examine how space radiation and high-energy particles affect their performance.

DaejeonSat-1, developed by regional space companies, will conduct Earth observation and test domestically developed payload technologies.

Other satellites will conduct Earth and space environment observations. CosmoWorks’ JACK-007 will image Earth using its own optical equipment. Quaternion’s PERSAT02, which failed to deploy, was supposed to track the movement of marine debris around Jeju Island and test Korean satellite components.

University-developed satellites will also conduct technology demonstrations. CPSat, developed by Chosun University and Pusan National University, will test optical communications using lasers and LEDs, while GBSAT, developed by a KAIST student team, will observe the radiation environment in low Earth orbit.

“The importance of the fifth launch lies in the fact that Korea’s independent launch capabilities are expanding to a stage where it can put space assets that perform actual national missions, such as national security and disaster response, into orbit on its own,” said An Hyoung-joon, associate research fellow at the Science and Technology Policy Institute.

“This launch demonstrates mission-oriented space transportation capabilities that go beyond simply carrying satellites into orbit to deploying them as a constellation system.”