[Q&A] Everything Was Perfect... KARI "Thankful for the Public's Support" [Nuriho 2nd Launch]

[Asia Economy Reporter Kim Bong-su] On the afternoon of the 21st at 4 PM, South Korea's first indigenous space launch vehicle, "Nuriho," successfully reached its target altitude of 700 km and entered satellite orbit during its second launch. This moment marks the happy ending of the 12-year "Korean Launch Vehicle Development Project" that began in 2010. The key developers, Korea Aerospace Research Institute (KARI) and officials from the Ministry of Science and ICT, expressed their deep emotions and announced plans to focus on the development of next-generation launch vehicles.

The following is a Q&A session held from 5:10 PM at the Naro Space Center briefing room with KARI Director Lee Sang-ryul and other officials.

- How did the second launch proceed?

△(Director Lee Sang-ryul) The second launch was successfully carried out. Nuriho was launched at 3:59:59 PM today and succeeded in reaching the target orbit and separating the performance verification satellite. Analyzing the remote reception results, according to the predetermined flight sequence, at about 123 seconds, the first stage separated at an altitude of 62 km; at 227 seconds, the fairing separated at 202 km; at 269 seconds, the second stage separated at 273 km; at 872 seconds, the performance verification satellite separated at 700 km altitude; and at 922 seconds, the satellite mock-up separated. The satellite was accurately deployed at the desired altitude. It meets the success criteria of the Nuriho launch, which is the target orbit of 700 km ± 5%. Communication with the Antarctic King Sejong Station was also successful, confirming the satellite's position. Tomorrow morning, the satellite's status will be checked through multiple communications with the Daejeon ground station. We once again thank the citizens who supported and encouraged us.

- Why were there slight second-level differences in the launch sequence?

△(Go Jeong-hwan, Head of KARI Korean Launch Vehicle Development Project) Some events occurred slightly earlier. Engine performance can vary slightly between units. The density of the fuel (kerosene) also varies each time, affecting performance. This is natural. This time, with better performance, events proceeded a bit faster. Overall, the final goal of the launch vehicle is to deploy the satellite into the target orbit, and since the performance verification satellite was deployed within the error range of the target orbit, it can be considered normal progress.

- After the incomplete first launch and two postponements of the second launch, you finally succeeded. How do you feel now?

△(Head Go) It would have been better if everything had gone smoothly last week, but variables always arise. Even yesterday, when the launch vehicle left the assembly building, everyone was anxious. We could only watch hoping for the best, and fortunately, it ended well. There is some regret that it did not go well last week. There is still a long way to go. We will analyze the results carefully and do better.

- What was the speed at satellite deployment?

△ (Director Lee Sang-ryul) The final goal of the launch vehicle is to accurately deploy the satellite at the desired orbit velocity. That is why we say it was successful. Of course, the speed of 7.5 km/s at 700 km altitude was precisely achieved.

- You have overcome many difficulties and challenges. Is there anything memorable?

△(Head Go) This is the 13th year of the project and the last year of this phase. The most memorable period was 2015-2016 when we faced technical difficulties. At that time, engine combustion was unstable, and after more than a year of hard work, we resolved it. Also, the development process of the propellant tank was not established, so the overall picture of the launch vehicle was unclear. It was a dark period when we did not know when it would be resolved or built. Another memorable moment was in May 2020 when we completed the 75-ton liquid engine and conducted combustion tests for the first time. The most fearful and relieving time was the combustion test of the first stage verification model in January, February, and March last year. We worried whether it would deliver the desired performance and withstand the test to completion. If it failed, the entire project would have been jeopardized. We watched with mixed worry and expectation, and it ended well.

- What are the plans for the third launch?

△(Jang Young-soon, Head of KARI Launch Vehicle System Development) Originally, the Korean launch vehicle development plan only included stage assembly for the third vehicle. The third vehicle was developed as a backup model in case of problems during the first and second flight tests. The goal is to complete stage assembly by the end of December. (With the success of the second launch) the third launch will correspond to the first launch of the Korean launch vehicle advancement project. The satellite to be carried will be the second next-generation small satellite, with the timing expected around early next year but not yet fixed.

- What is the communication status between the satellite and ground station?

△(Ahn Sang-gil, KARI Deputy Director) The exact communication time needs to be checked. We received signals exactly at the expected time. Reviewing the satellite data, the most important attitude control and battery status were confirmed to be better than expected. The battery remained almost fully charged, and the satellite attitude was stable after separation and is currently confirmed to be good. Detailed checks will be conducted through communication with the Daejeon ground station early tomorrow morning. Since the satellite is equipped with a Global Positioning System (GPS), accurate orbital data will be obtained tomorrow. Comprehensive inspection will take about a week. Starting from the 29th, eight days after launch, the CubeSats mounted on the performance verification satellite will be deployed.

- How was the sensor malfunction repaired?

△(Oh Seung-hyeop, KARI Deputy Director) On the 15th, during flight preparations, there was an issue with the first stage oxidizer tank level sensor. The repair was done without anyone entering inside; the inspection window at the connection between the first and second stages was opened. Only the sensor core of the first stage oxidizer tank was removed, checked, and replaced.

- What was President Yoon Seok-yeol's reaction?

△(Deputy Director Oh) I heard the president's remarks through the control room monitor. What I remember is his encouragement for overcoming difficulties and achieving success. Regarding his campaign promise to establish the Aerospace Administration, he emphasized the need to realize it and pledged full support for the aerospace sector, urging us to continue research on next-generation launch vehicles and follow-up studies.

- Any message to the public?

△(Kwon Hyun-jun, Director of the Ministry of Science and ICT) This year marks 30 years since South Korea launched its first scientific rocket in 1993 and 20 years since developing a liquid rocket in 2002. The efforts of the past 30 and 20 years have finally borne fruit. We are grateful to receive the results of the efforts made by our predecessors. We thank the public once again for their support and encouragement.

(Head Go) The good results today bring joy both personally and to the public. It took a long time. Nevertheless, thanks to the unwavering support and encouragement from the public, we have come this far. With the successful launch of Nuriho, we have taken the first step. This is not the end; the possibilities are endless regarding what to do next and how to develop follow-up launch vehicles. South Korea's path to space has opened, and everything is open for what to do next. This is just the beginning. We ask for more encouragement and support in the future. Especially, please help children in each household to take an interest in science and technology.

(Director Lee Sang-ryul) Once again, thank you for your support. Although South Korea has made great progress, even during times of stagnation, we dreamed challenging dreams through space and achieved success. Please continue to be with us.

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