South Korea's solidâÂÂfuel space launch vehicle, commonly abbreviated GYà ªB (Korean: Goche Yeonlyo Uju Balsache or ê³ ì²´ì°룠ì°주ë°Âì¬체), is an orbital booster under development by the state-run Agency for Defense Development (ADD). It is based on solid propellant stages, with a liquid-fuel postâÂÂboost stage (PBS), designed to deploy small satellitesâÂÂparticularly synthetic aperture radar (SAR) reconnaissance payloadsâÂÂinto low Earth orbit as part of the country's independent space-based surveillance capability.
ADD plans the first launch of a complete version of the launcher, capable of placing a one-ton satellite into a sun-synchronous orbit , in 2027. By 2032, the military expects to have a version capable of placing 7 tonnes into a sun-synchronous orbit and 3.7 tonnes into a geostationary transfer orbit.
The rocket has three solidâÂÂfuel stages, followed by a liquidâÂÂfueled fourth "postâÂÂboost" stage (PBS) to enable precise payload deployment. The first stage is mentioned to produce "a thrust that is one-and-a-half times stronger than North KoreaâÂÂs solid-fuel engines", or around 245 tones. The second stage produces 75 tons of thrust. The GYà ªBâÂÂTV2 version, launched in December 2023, had an estimated take-off thrust of 170 tonnes with the capacity to place 700 kilograms in low orbit.
Two suborbital launches of a version called TV1 (Test Vehicle 1), comprising only the last three stages, were carried out in 2022 from Anhueng. TV2 is an incomplete version of the final launch vehicle, consisting of only the 1st, 3rd, and 4th stages. It was launched on December 4, 2023, from a barge off Jeju Island.