South Korean rocket puts satellites in orbit for the first time in second flight

SEOUL, South Korea — South Korea’s homegrown rocket KSLV-2 successfully put satellites into low Earth orbit for the first time in its second flight June 21. A performance test satellite, deployed from the rocket about 14 minutes after liftoff, exchanged its first signals with a ground station associated with South Korea’s research center in Antarctica about 42 minutes after liftoff, according to the science and technology ministry. The satellite will deploy four smaller satellites developed by domestic universities in the coming days.

“We have arrived at a monumental moment not just in South Korea’s science and technology history but for South Korea’s history as well,” science minister Lee Jong-ho said in a televised press conference at the Naro Space Center. “This is a milestone we achieved nearly 30 years after the country launched its first sounding rocket in June 1993.” The minister said the government will conduct four additional KSLV-2 launches by 2027 as part of efforts to further advance the country’s space rocket program.

President Yoon Suk-yeol hailed the success at his office in Seoul, saying, “the road to space from the Republic of Korea has opened.”

The kerosene and liquid oxygen-fueled three-stage rocket KSLV-2 lifted off at the planned time of 3 a.m. EST from the Naro Space Center. Live footage showed the 47.2-meter rocket, emblazoned with South Korea’s flag, soaring into the air with bright yellow flames shooting out of its engines. The first-stage booster, powered by a cluster of four KRE-075 engines, was separated at 3:02 a.m. Eastern as planned, according to the ministry. The separation of its payload fairing took place about one minute and forty seconds later, and the second stage booster with a single KRE-075 engine at 3:04 a.m. The third stage with a KRE-007 engine pushed the payload to the intended orbit of 700 kilometers above the Earth and deployed the performance test satellite at 3:14 a.m. at the orbital velocity of 7.5 kilometers per second, according to the ministry.

In the maiden flight last year, KSLV-2 reached its intended altitude, but its third-stage engine shut down 46 seconds early, releasing its 1,500-kilogram dummy payload at less than orbital speed. The dummy payload fell back to Earth south of Australia. The premature engine shutdown was later blamed on improperly anchored helium tanks inside the upper stage. The Korean Aerospace Research Institute (KARI), responsible for the rocket’s development, fixed the flaw by reinforcing the structure anchoring the helium tanks.

KSLV-2’s second launch was initially set for June 15, with a backup launch window spanning June 16-23. However, it was delayed to the following day due to strong winds. It was delayed again after engineers found a problem with a sensor inside the oxidizer tank of the rocket’s first-stage booster during a final pre-launch checkup at the launch pad. KARI said readings on the malfunctioning sensor remained static when the tank was being loaded. To fix the problem, the rocket was pulled off the launch pad and rolled back to the hangar June 15. KARI confirmed that the problem was confined to the sensor and replaced it with a new one. Then it set June 21 as the rocket’s launch date.

KSLV-2 — which cost South Korea an estimated 2 trillion won ($1.6 billion) to develop — is the first step for South Korea’s ambitious space program, including the launch of the nation’s first robotic lunar lander on a domestically developed rocket by 2030. 

The country had previously launched a space launch vehicle from Naro Space Center in 2013, a two-stage rocket built mainly with Russian hardware. That launch came after years of delays and consecutive failures. The rocket, KSLV-1, reached the desired altitude during its first test in 2009 but failed to eject a satellite into orbit, and then exploded shortly after takeoff during its second test in 2010.