SEOUL, Dec. 13 (Yonhap) -- North Korea's satellite delivered by its long-range rocket was circling the Earth with an orbital period of 95.4 minutes, Seoul's defense ministry said Thursday, but it was not yet known whether it was functioning properly.
A day after the communist state's successful, surprising multistage rocket launch, the defense ministry acknowledged that the Kwangmyongsong-3 satellite was circling the Earth at a speed of 7.6 kilometers per second, citing data by the North American Aerospace Defense Command, or NORAD. The oval radius has a perigee altitude of 505 km and an apogee altitude of 580 km.
"It is not yet known what kind of mission the satellite is conducting," the ministry spokesman Kim Min-seok said in a briefing. "It usually takes two weeks to evaluate whether a satellite is successful. For the time being, it is working normally."
Although the communist state claims Wednesday's launch was meant to send a peaceful satellite into space, the South Korean government sees it as a covert test for ballistic missile technology and the launch means it is a step closer to perfecting an intercontinental ballistic missile, Kim said.
The three-stage rocket has an estimated range of 10,000 kilometers, Kim said, which can fly over the Pacific Ocean to hit the U.S.
"If the North replaces the satellite with a nuclear war head, it could turn into an intercontinental ballistic missile," Kim said.
The Korean Aerospace Research Institute (KARI) also confirmed the satellite has been placed on an elliptical orbit, citing the NORAD data, though Pyongyang had intended to put it on a circular orbit with a radius of 500 km.
"If the satellite circles an oval orbit, not a circular orbit, the duration of continuous shooting is lengthened in certain regions," said Lee Kyu-su, a public relations official at the KARI.
While a large satellite can correct its path with the help of a small booster, the North's 100-kg satellite is not equipped with such equipment, and thus will be stuck in an elliptical orbit, Lee said.
Since Pyongyang has tested two nuclear devices since 2006, it has been upgrading its atomic technology to conduct another test "when time is ready," he said.
The South Korean military has deployed Aegis warships and minesweeping ships in the western sea and they are now searching for debris from the rocket.
Less than two hours after liftoff Wednesday, an Aegis destroyer discovered an object, believed to be part of a fuel container from the first stage of the rocket, in the Yellow Sea located near the trajectory announced by the North, the ministry said. The Navy will deploy a Deep Submergence Rescue Vehicle to retrieve the object later in the day.
"It is currently submerged about 80 meters under the sea," spokesman Kim said. "The military will start retrieving it when the tide changes at around 4 p.m."
The 6-meter long, 1.6-meter wide container, which has the name "Unha" lettered on the rocket, is expected to give an early glimpse into the type of fuel and materials used as well as the amount of thrust of the rocket, the spokesman said. noting Seoul has no intention of returning the fallen object to Pyongyang.
"We are not obligated to return it as (Seoul) considers it as an enemy's weapon and the launch was done in violation of the U.N. Security Resolution 1874," which bans the isolated country from testing a ballistic missile, Kim said.
The rocket's first stage fell in waters west of the Korean Peninsula, while the second stage landed in the sea east of the Philippines, about 2,600 kilometers away from the launch site.
Although the debris could give an early glimpse of the rocket's components and capability, the military has no plan to disclose the details, they noted.
Ahead of the launch, the North had sent missile scientists and equipment in late November to some Asian nations, like China, Mongolia and Indonesia, said the Washington-based Radio Free Asia as well as a senior source in Seoul.
"It appears that the equipment set up in China and Mongolia is aimed at tracking the satellite," spokesman Kim said. "Because the satellite circles very fast, it briefly passes through North Korea. Therefore, several regions need antennas to track it."
In light of the communist rival's latest development, Seoul military officials say they plan to speed up preparations for a comprehensive missile defense system to better counter threats from North Korea, the so-called "kill chain," which can detect, target and destroy ballistic missiles.
Military officials of South Korea and the U.S. will hold a working-level meeting to map out measures, including upgrading the anti-missile Patriot 2 system or purchasing the PAC-3 system, which employs hit-to-kill technology.
In a defense ministerial meeting in October, the two allies had agreed to jointly develop the kill chain by 2015.
Seoul bought 48 PAC-2 systems, including launchers, from Germany at a cost of 1 trillion won (US$909 million), but a recent study showed the PAC-2 system's interception success rate remains below 40 percent.
The South Korean military has also stepped up the security level on a nuclear test site in the North's northeast to detect signs of another test.
"We believe the North is ready to conduct a nuclear test within days if it has a political determination to do so," a senior military official said, noting there is no sign of an "imminent" test.