South Korean rocket launches satellite

South Korea has conducted its first successful satellite launch using a domestically developed rocket, boosting its growing aerospace ambitions.

The launch on Tuesday also demonstrated it has key technologies needed to launch spy satellites and build larger missiles amid tensions with rival North Korea.

The three-stage Nuri rocket placed a functioning "performance verification" satellite at a target altitude of 7km after its 4pm liftoff from South Korea's space launch centre on a southern island, the Science Ministry said.

The satellite transmitted signals about its status to an unmanned South Korean station in Antarctica. It is carrying four smaller satellites that will be released in coming days for Earth observation and other missions, ministry officials said.

"The science and technology of the Republic of Korea have made a great advance," Science Minister Lee Jong-Ho said in a televised news conference at the launch centre. "The government will continue its audacious march toward becoming a space power together with the people."

In a video conference with scientists and others involved in the launch, President Yoon Suk Yeol congratulated them for their achievement and vowed to keep his campaign promise to establish a state aerospace agency.

Live TV video showed the 47-metre rocket rising into the air amid bright flames and thick white smoke.

The launch made South Korea the world's 10th nation to place a satellite into space with its own technology.

It was South Korea's second launch of a Nuri rocket. In the first attempt last October, the rocket's dummy payload reached the desired altitude but didn't enter orbit because the engine of the rocket's third stage burned out earlier than planned.

North Korea placed Earth observation satellites into orbit in 2012 and 2016, though there is no proof that either one has ever transmitted spaced-based imagery and data back home.

The North Korean launches resulted in UN economic sanctions because they were viewed as covers for testing the country's banned long-range missile technology.

Since the early 1990s, South Korea has sent a slew of satellites into space, but all used foreign rocket technology or launch sites. In 2013, South Korea successfully launched a satellite for the first time from its soil, but the first stage of the rocket was Russian-made.

South Korea plans four more Nuri launches in coming years. It also hopes to send a probe to the moon, build next-generation space launch vehicles and send large-scale satellites into orbit.

South Korean officials said the Nuri rocket has no military purposes.

"If you put a satellite on the top of a rocket, it would become a space launch vehicle. But if you mount a warhead on it, it becomes a weapon," said Kwon Yong Soo, a former professor at Korea National Defense University in South Korea.

"(A successful launch) is really meaningful because we also succeed in the test of a long-range rocket that can be used to build a long-range missile."

South Korea already has missiles that can hit all of North Korea, but some experts say it also needs longer-range missiles because it's surrounded by regional military powers and potential adversaries.

"If we only think about North Korea, a long-range missile doesn't mean much for us. But it's very unfortunate that military powers like China and Russia are near us," Kwon said.

He said Nuri's successful launch proves South Korea has the capability to send a spy satellite into orbit.

South Korea currently has no military reconnaissance satellites of its own and depends on US spy satellites to monitor strategic facilities in North Korea. South Korea has said it plans to launch its own surveillance satellites soon.