South Korea s first domestically produced space rocket reached its desired altitude but failed to deliver a dummy payload into orbit in its first test launch.
The South Korean president, Moon Jae-in, still described the test as an excellent accomplishment that takes the country a step further in its pursuit of a space launch programme.
Live footage showed the 47 - metre 154 ft rocket soaring into the air with bright yellow flames shooting out of its engines following blastoff at Naro Space Center, the country s lone spaceport, on a small island off its southern coast.
After the launch, the Korea Aerospace Research Institute Kari, the country s space agency, reported that Nuri s first and second stages separated properly and that the third stage carried the payload a 1.4 - tonne block of stainless steel and aluminium 435 miles above Earth. But Moon, who observed the launch at the Naro spaceport, said in a televised speech that the payload did not stabilise in orbit after being separated from the third stage.
Officials from Kari and South Korea s science ministry provided no more immediate details on what went wrong.
The launch, which took place at 5 pm 0900 BST was delayed by an hour because engineers needed more time to examine the rocket s valves. There had also been concerns that strong winds and other conditions would pose challenges for a successful launch.
Although the launch failed to achieve its objectives perfectly, it was an excellent achievement for a first launch, Moon said.
The midair engine ignitions and the separations of the rockets, fairings covering the payload and the dummy satellite worked smoothly. All this was done based on technology that is completely ours, he added.
After relying on other countries to launch its satellites since the early 1990 s, South Korea is now trying to become the 10th nation to send a satellite into space with its own technology.
Officials say such an ability would be crucial for the country s space ambitions, which include plans for sending more advanced communications satellites and acquiring its own military intelligence satellites. The country is also hoping to send a probe to the moon by 2030.
Nuri is the country s first space launch vehicle built entirely with domestic technology. The three stage rocket is powered by five 75 ton class rocket engines placed in its first and second stages.
Scientists and engineers at Kari plan to test Nuri several more times, including conducting another launch with a real device in May 2022, before testing with a dummy satellite.
South Korea had previously launched a space launch vehicle from the Naro spaceport in 2013. It was a two stage rocket built mainly with Russian technology. That launch came after years of delays and consecutive failures. The rocket, named Naro, reached the desired altitude during its second test in 2009 but failed to eject a satellite into orbit and then exploded shortly after takeoff during its first test in 2010.
It was unclear how North Korea, accused of using its space launch attempts as a disguise for developing long-range missile technology, would react to Thursday's launch.
While pushing to expand its nuclear and missile programme, the North had shown sensitivity about South Korea s increasing defence spending and efforts to build more powerful conventionally armed missiles.
In a speech to Pyongyang s rubberstamp parliament last month, the North Korean leader, Kim Jong-un, accused the US and South Korea of destroying the stability and balance in the region with their excessive military activities and a US-led military buildup in the South.
While Nuri is powered by solid propellants that need to be fuelled shortly before launch, the South Koreans plan to develop a liquid fuel space launch rocket by 2024, which could be cheaper to build and ready for launch more quickly. Such rockets would also be ideal for more sensitive space launches, including those involving military intelligence satellites.
South Korea s space ambitions have been boosted in recent years as the Trump and Biden administrations took steps to ease decades-long US restrictions that capped Seoul missile development before eventually allowing its ally to build conventional weapons with unlimited range and warhead weight. In easing the so-called missile guidelines, the US also removed a limit on the power of solid-fuel rockets South Korea could build for space launch purposes.
South Korea currently has no military surveillance satellites of its own, which leaves it relying on US spy satellites to monitor North Korea. Officials have expressed hopes of launching domestically developed, low-orbit military surveillance satellites using the country s own solid-fuel rockets in the next several years.