North Korea has bristled at UN sanctions imposed after its April launch, which US intelligence officials say did not place a satellite in orbit but in reality was cover for a test of long-range missile technology.
Series of delays
Tuesday's South Korean launch took place after a series of delays put a hold on previous attempts.
Last week blast-off was aborted with just minutes to go after technicians discovered a software fault.
Ahead of the launch scientists had warned the first seconds of flight would be crucial as the main engine pushes the 140-tonne rocket off the launch pad.
"If there is a sudden gust of strong wind or any other slight problem in the stabilisation mechanism, the rocket can tip over and be lost," Min Kyung-Ju, head of the Naro Space Centre, told South Korea's Yonhap news agency.
A successful launch would make South Korea only the 10th nation in the world to send a satellite into orbit from its own soil.
Although the rocket's powerful first stage was Russian-made, South Korean experts said they had gained valuable know-how that could enable them to build their own launch vehicle in its entirety by 2018.
Neighbouring North Korea launched its own three-stage rocket on April 5 claiming it sent a communications satellite into orbit, but there were doubts the mission succeeded.
The United States, Japan and others have called Pyongyang's rocket launch a cover for test of long-range missile technology.
The UN Security Council also condemned the launch, saying it was a violation of resolutions banning North Korea from ballistic missile-related activity.
The North responded by expelling inspectors and withdrawing from six-party talks on the disarmament of its nuclear programme.
Ahead of Tuesday's launch Won Tae-jae, a South Korea defence ministry spokesman, defended his country's space programme saying the launch vehicle differed vastly from the North's controversial rocket launches.
He told reporters during a regular briefing that the development of South Korea's space launch vehicle has been responsible and open to the international community.
"On that matter, we are not accused of launching a ballistic missile," he said.