SEOUL: South Korea’s first space rocket blasted off today in a long-delayed launch but failed to place a satellite into its designated orbit, officials said.

In an event watched guardedly by rival North Korea, the Korea Space Launch Vehicle-1 lifted off on schedule at 5:00 pm (0800 GMT) atop a tail of flame, to the jubilation of officials at the Naro Space Centre.

The first stage separated successfully less than five minutes after lift-off and the South Korean-built 100-kg scientific research satellite was placed into Earth orbit.

But science and technology minister Ahn Byong-Man said it was not following the designated orbit, hampering communications with mission control.

“All aspects of the launch were normal, but the satellite exceeded its planned orbit and reached an altitude of 360 km,” Ahn said.

It should have separated at around 302 km.

“A joint probe is under way by South Korean and Russian engineers to find the exact cause,” the minister said.

Experts from the Korea Aerospace Research Institute told Yonhap news agency they were trying to track the whereabouts of the satellite and declined to say if contact could be made later.

They said despite the satellite’s failure to reach its proper orbit, the launch should be seen as a “half success” since the rocket functioned without any problem.

“The rocket was successfully launched. I congratulate our people,” Prime Minister Han Seung-Soo said earlier from the launch site at Goheung on the south coast.

North Korea, which is smarting over UN Security Council censure of its own rocket launch in April, had vowed to closely monitor the launch.

Pyongyang insists it was unfairly punished for its April 5 launch, saying it merely put a peaceful communications satellite into orbit.

It wants Seoul’s launch also to be referred to the Security Council.