Nuri rocket to carry 15 satellites in 5th launch, opening South Korea's private space era

South Korea's homegrown Nuri rocket is set to attempt its fifth launch Oct. 7, carrying 15 satellites — five ultra-small cluster satellites and 10 CubeSats. The launch is expected to serve as a proving ground for the private sector's takeover of manufacturing and launch technologies developed by the government and the Korea Aerospace Research Institute, with the goal of eventually operating an independent space transportation service.

The fifth launch will see significantly expanded participation by a private systems integrator in manufacturing, assembly and launch operations, and will also mark the first application of a new technology for precisely separating multiple satellites.

According to the Korea Aerospace Research Institute, the fifth Nuri launch is scheduled for between 12:23 p.m. and 1:23 p.m. on Tuesday.

The target orbit is a sun-synchronous orbit at an altitude of 570 kilometers. The satellite payload section weighs approximately 1,071 kilograms in total: about 500 kilograms for the five primary payloads — ultra-small cluster satellites Nos. 2 through 6 — about 96 kilograms for the 10 CubeSats, and about 475 kilograms for satellite ejection devices and adapters.

Another highlight of this launch is what officials are calling a "cluster satellite launch service."

Once Nuri reaches its target altitude, it will release the five ultra-small cluster satellites one by one at 35-to-40-second intervals, followed by the 10 CubeSats in pairs at 10-second intervals. The exercise goes beyond placing a single satellite into orbit — it tests the rocket's capacity to deploy multiple satellites in a set sequence and on a precise timetable.

Nuri itself has also been upgraded for the task. A low-impact satellite separation system — designed to reduce separation shocks to levels comparable to those of foreign launch vehicles — is being applied for the first time. The system, developed from Nuri's existing small satellite separation device, uses an integrated clamp-band mechanism. A new lower ring for mounting secondary payloads has also been added.

The fifth launch is drawing particular attention as a sign that the handover of Nuri to the private sector has entered a substantive phase.

In the first through third Nuri launches, the Korea Aerospace Research Institute led vehicle manufacturing and final assembly, with participating companies in a supporting role. From the fourth launch onward, Hanwha Aerospace, as the designated systems integrator, took the lead on manufacturing and assembly, with the institute overseeing and supervising.

In the fifth launch, the private sector's role expands to launch operations. Hanwha Aerospace will staff 20 of the 22 consoles at the Launch Control Center with 23 personnel, 18 of whom will directly operate consoles.

The government is transferring domestically developed launch vehicle technology to the private sector through the Nuri upgrade project. By participating in the fourth through seventh Nuri launches, Hanwha Aerospace is building the technical expertise and operational experience needed to independently manufacture and operate launch vehicles once the government's upgrade program concludes.

The Nuri upgrade project will receive a total of 796.88 billion won ($586 million) from 2022 through 2028. Its core objectives are to enhance Nuri's reliability through repeated launches and to transfer launch vehicle manufacturing and operations technology to the private sector.

The government and the Korea Aerospace Research Institute are also focusing on developing reusable launch vehicle technology that would allow rockets to be recovered and reflown.

The institute is developing a demonstrator to verify key reusable launch vehicle technologies. The vehicle will weigh about six metric tons at liftoff, measure 12.2 meters in length and 1.5 meters in diameter, and will ascend to approximately 500 meters before returning to a vertical landing. It will use a ground development model of a 10-ton-class staged-combustion cycle engine intended for the upper stage of the next-generation launch vehicle.

Ultimately, the technologies gained through Nuri will feed into the next-generation launch vehicle, designated KSLV-III. The KSLV-III is being developed as a two-stage rocket designed with reusability in mind. The first stage will carry nine 80-ton-class engines burning liquid oxygen and liquid methane, with one such engine on the second stage. The program also plans to incorporate reusability technologies including grid fins, thrust vector control systems and landing legs.

"The technical goal of the fifth Nuri launch is to place 15 satellites precisely into their target orbits," said Han Yeong-min, director of the Space Launch Vehicle Research Center at the Korea Aerospace Research Institute. "The bigger goal, once the sixth and seventh launches are complete, is for the systems integrator to have the capability to conduct launch operations entirely on its own."