The secretive state of North Korea has made its second attempt to fire a rocket into space this year. Reuters reports that South Korea's Defense Ministry confirmed the launch, which is set to pass over China and Okinawa before a part is jettisoned into the Philippines. The Japanese military has been placed on alert, and South Korean president Lee Myung-bak has called an emergency meeting, according to Yonhap. At this point, it's unclear whether or not the launch has been successful. North Korea claimed it successfully put a satellite in orbit back in April 2009, but sources including the US military reported it to have been a failure.

The launch follows the failed Unha-3 attempt in April, which crashed into the sea shortly after takeoff. North Korea argues that it is entitled to peaceful space exploration, but has faced widespread international criticism that the program is a cover for testing long-range ballistic missiles. While the country has long pursued nuclear development, there are serious doubts over its ability to actually launch a nuclear weapon.

Update: The launch appears to have been a success; Yonhap has reported statements saying as much from the North and South Korean governments.

Update 2: Martyn Williams of IDG News has got hold of a Korean Central News Agency news bulletin announcing the rocket launch's success. The KCNA is North Korea's state news agency, and said "The launch of the second version of our Kwangmyongsong-3 satellite from the Sohae Space Centre on December 12 was successful. The satellite has entered the orbit as planned."

Update 3: You don't have to take North Korea's word for it — NORAD has just released a statement that lends credence to the claims of successful orbit. We've reproduced it below.

North American Aerospace Defense Command officials acknowledged today that U.S. missile warning systems detected and tracked the launch of a North Korean missile at 7:49 p.m. EST. The missile was tracked on a southerly azimuth. Initial indications are that the first stage fell into the Yellow Sea. The second stage was assessed to fall into the Philippine Sea. Initial indications are that the missile deployed an object that appeared to achieve orbit. At no time was the missile or the resultant debris a threat to North America.