Why is 'Nuriho = Space Independence'? ... Let's Understand This First [Reading Science]

First Launch of Korean Space Launch Vehicle on the Afternoon of the 21st
Securing Independent Space Development Capability, Advancing to the World's Top 7 Space Powers
Enabling Stake Acquisition by Confidently Participating as a Partner in International Space Cooperation
Significant Impact on NewSpace Era, Activation of Private Space Industry, and Pioneering 'Future Growth Engines'

[Asia Economy Reporter Kim Bong-su] On the afternoon of the 21st, Korea’s indigenous space launch vehicle, ‘Nuriho (KSLV-2),’ carrying the dream of South Korea’s ‘space independence,’ will embark on its maiden flight. Development began in 2010 with a budget of 1.9572 trillion won, and Nuriho was completed using 100% domestically developed technology. If successful, South Korea will join the ranks of the world’s top seven space powers. This will play a significant role in national security and improving the quality of life for citizens, as well as allow South Korea to participate confidently in international space development and secure its stake. The economic impact, including the activation of the private space industry, is also considerable.

-What are the key points to watch during the Nuriho launch process and the ‘success criteria’?

▲The success of the Nuriho launch will be determined within 16 minutes. First, it is crucial that the combustion and propulsion of each stage proceed normally: 127 seconds for the first stage, 147 seconds for the second stage, and 521 seconds for the third stage. Additionally, immediately after the first stage combustion, the payload fairing (the cover of the cargo compartment) must separate properly. Finally, success is achieved if the dummy satellite loaded on board is placed at an altitude of 700 km at a speed of 7.5 km/s. The Korea Aerospace Research Institute (KARI) expects success, noting that the core 75-ton liquid engine’s performance was somewhat verified during a test launch in November 2018. However, historically, the success rate of the first flight of space rockets worldwide is about 28%. The Ministry of Science and ICT requests that the term ‘abnormal flight’ be used rather than ‘failure.’ Since the space launch vehicle technology is already secured, retries are possible, and all countries, including the U.S., have gone through ‘trial and error.’

-What is the source of the massive white smoke during launch?

▲The day before the launch, Nuriho is transported and erected at the second launch pad of the Naro Space Center. On the launch day morning, propellant and oxidizer are loaded, and an automatic computer countdown begins 10 minutes before launch. At the end of the countdown, the first-stage engine ignites automatically. Propellant and oxidizer equivalent to five drums (1,000 kg) explode per second, generating thrust. After a few seconds, when maximum thrust of 300 tons is reached, the fixed device (VHD) is released, and Nuriho heads skyward. The white smoke coming from below the launch pad is not toxic gas but water vapor. Water is sprayed underground to prevent the launch pad from melting due to the extreme heat of 3,300 degrees Celsius. The white substance falling from the body immediately after liftoff is ice. This is because the oxidizer (liquid oxygen) used with the propellant (kerosene) is at an extremely low temperature of minus 183 degrees Celsius.

-Why is South Korea considered one of the world’s top seven space powers?

▲Currently, ten countries possess space launch vehicles: the United States, Russia, China, Japan, India, the European Union (EU/France), Israel, Iran, North Korea, and Ukraine. South Korea will become the 11th country to possess a space launch vehicle. However, Israel, Iran, North Korea, and Ukraine’s vehicles are essentially for military use, i.e., intercontinental ballistic missiles (ICBMs), or have inferior performance. Nuriho can carry a payload of 1.5 tons to an altitude of up to 700 km. Only six countries?the U.S., Russia, China, Japan, India, and the EU?have the technology to carry practical satellites weighing over 1 ton (medium class). Additionally, South Korea is evaluated to have reached a considerable level in satellite manufacturing, having independently developed large-class ‘Cheollian satellites’ weighing 2.5 tons and next-generation medium-class satellites.

-Why is it called ‘space independence’?

▲The world has entered the New Space era. It is no longer a game played only by superpowers to showcase national strength or satisfy curiosity. There is a growing necessity to engage in space development to secure practical national interests. To protect one’s satellites and territory from asteroids and space debris, and for military and economic reasons, the need for an independent space launch vehicle is urgent. Already, space powers like the U.S. are launching over 1,000 satellites annually to build next-generation satellite internet and 6G ultra-high-speed satellite communication networks. As autonomous driving technology, artificial intelligence (AI), and urban air mobility (UAM) are actively developed, securing satellite big data and independent GPS is becoming necessary. This is why the South Korean government plans to launch about 100 satellites, including the Korean Positioning System (KPS), by 2030. Private companies such as Hanwha Aerospace and Hancom Group are also entering the satellite manufacturing, launch, and service industries.

South Korea must possess an independent space launch vehicle to meet such demands promptly. Moreover, as underground resources become increasingly depleted and humanity looks toward the distant future, space resource development and deep space exploration activities are intensifying. To be recognized as a partner and secure a stake in international space development cooperation systems, possessing an independent space launch vehicle is essential. Professor Heo Hwan-il of Chungnam National University’s Department of Aerospace Engineering said, “Security in space will become extremely important in the future. Except for South Korea, the U.S., Russia, Japan, and China all have space forces,” adding, “Our Air Force also has a blueprint to expand and reorganize into an Aerospace Force by 2050, and an independent space launch vehicle is an essential element.”

-Was South Korea late compared to North Korea, and did it copy Russia?

▲North Korea succeeded in launching the Hwasong-15 intercontinental ballistic missile (ICBM) in November 2017. It is known to have used the ‘Baekdu engine,’ a modified 80-ton thrust engine based on Russia’s 90-ton RD-250 engine leaked from Ukraine. North Korea also conducted a combustion test on December 7, 2019, at the West Sea Satellite Launching Station in Dongchang-ri, West Sea, clustering four Baekdu engines. However, it has not yet succeeded in launching a vehicle clustering four engines. In contrast, South Korea developed a 75-ton liquid engine and succeeded in a test launch in November 2018. If the first launch on the 21st, including clustering four engines in the first stage, succeeds, South Korea will surpass North Korea in space launch vehicle development at once.

Claims that South Korea copied Russian technology are also dismissed by experts. South Korea did use a Russian-made first-stage rocket (170-ton thrust) for the Naroho, which successfully launched in January 2013. However, Lee Chun-geun, honorary research fellow at the Science and Technology Policy Institute (STEPI), said, “The Nuriho engine succeeded after tremendous difficulties, including changing the design more than ten times and conducting over 100 combustion tests over 12 years to resolve combustion instability,” and dismissed the claim that South Korea copied Russian technology as “absurd.”

-Domestic technologies to watch.

▲Nuriho was developed with 100% domestic technology. Among these, the ‘three core technologies’?rocket engine, propellant tank, and payload fairing?are fundamental technologies of space launch vehicles and are classified as highly difficult and top secret by space powers. The 75-ton engine, which emits flames exceeding 3,300 degrees Celsius, originated from the 30-ton prototype engine developed during the Naroho project. KARI studied classic textbooks from the U.S. and Russia and examined old engines in overseas museums, mastering the technology and experiments before succeeding in engine development. A total of 33 prototypes were made, and 184 combustion tests were conducted for a total of 18,290 seconds. Moreover, clustering technology that combines four engines into one was also acquired. The propellant tank, made of a special aluminum alloy about 2 mm thick, was developed through numerous trials and errors using domestic technology. It required much higher precision, advanced welding technology, and excellent concentration than computer simulations. The payload fairing technology, the ‘finishing touch’ of the space launch vehicle, was secured after more than 200 separation tests, repeatedly correcting problems, culminating in the success of the third Naroho launch in January 2013.