Pressure is building on South Korea's beleaguered space agency after two failed attempts to launch a satellite over the last three years.
The latest attempt follows an August 2009 satellite which plummeted back to earth after failing to separate from its rocket and a June 2010 explosion just two minutes 17 seconds after launch.
If it completes its mission, the third rocket, known as Naro-3, will make South Korea the 10th country to have joined the space race successfully. It will be the 4th in Asia, after Japan, China and India.