by Douglas Messier
South Korea has set an October date for the maiden flight of the nation’s first fully domestically developed satellite launch vehicle, the Korea Aerospace Research Institute (KARI) announced. Minister of Science, ICT and Future Planning Hyesuk Lim approved KARI’s plan to conduct flight tests of the new Nuri booster from the Naro Space Center on Oct. 21 and May 19, 2022.
KARI said the first rocket will carry a dummy satellite weighing 1,500 kg (3,307 lb). The second booster will orbit a dummy satellite weighting 1,300 kg (2,866 lb) and a performance verification satellite weighing 200 kg (441 lb). The goal of the flight tests is to place the satellites into a 700-km (435 mile) high sun synchronous orbit (SSO).
Nuri, which is also known as Korean Satellite Launch Vehicle II (KSLV-II), is designed to give South Korea its own domestic launch capability and to allow the nation to compete on the international market. Five other Asia-Pacific nations — China, India, Japan, New Zealand and North Korea — have launched satellites into orbit from their own soil.
The October flight will be South Korea’s first domestic orbital launch attempt in more than eight years. On Jan. 30, 2013, a Naro-1 rocket placed the STSAT-2C technology demonstration satellite into low Earth orbit.
It was the final of three launches for now retired Naro-1, which consisted of a Russian Angara first stage with a downgraded engine and a South Korean developed solid-fuel upper stage. Two previous Naro-1 launches failed in 2009 and 2010.
Nuri is a three-stage, 47.2 meter (155 foot) tall booster capable of placing 1,500 kg (3,307 lb) into a 600-800 km (373-497 mile) high low Earth orbit (LEO) and 2,600 kg (5,732 lb) into a 300 km (186 mile) high orbit. Nuri has a gross weight of 200,000 kg (440,925 lb) and a diameter of 3.5 meters (11.5 feet).
Nuri’s first stage is powered by four KRE-075 engines with a specific impulse of 289.1 seconds. A single KRE-075 vacuum engine powers the second stage, with one KRE-007 engine on the third stage. All six engines were developed by South Korean engineers and use Jet A-1 fuel and liquid oxygen.
According to the KARI website, 17 KRE-075 engines had been built and tested 146 times with a cumulative combustion time of 14,365 seconds as of February 2020. The single longest KRE-075 burn time was 260 seconds. Nine KRE-007 engines were developed and tested 77 times, with a cumulative combustion time of 12,326 seconds.
On Nov. 28, 2018, KARI launched the single stage Test Launch Vehicle (TLV) to evaluate the KRE-075 engine in flight. The engine burned for 151 seconds during a 10-minute flight that saw the TLV reach an altitude of 209 km (130 miles). KARI declared the flight test to be a success.
KARI designed the rocket with Hanwha Aerospace manufacturing the engines. Korea Aerospace Industries oversees final assembly of the booster. Hyundai Heavy Industries built the launch pad. Development costs are estimated at 1.96 trillion won (US $1.7 billion), which includes spaceport development.
Engineers are working to developed a lighter and more powerful version of the KRE-075 engine that would increase Nuri’s payload from 1,500 kg (3,307 lb) to 2,800 kg (6,173 lb).
Engineers also have plans to develop a Nuri variant capable of launching satellites into geosynchronous orbit. The first stage will be powered by four KRE-090 engines with four side boosters each equipped with a single KRE-90 engine. The second stage will be powered by a KRE-090 engine, and the third stage by a KRE-010 engine.