The South Korean Defense Ministry said the satellite launched by North Korea Wednesday was circling the Earth with an orbital period of 95.4 minutes but its success will not be known for about two weeks, Yonhap News Agency reported.
The ministry, quoting data from the North American Aerospace Defense Command, said the Kwangmyongsong-3 satellite was circling the Earth at 4.7 miles per second, with an oval radius of up to 367 miles.
"It is not yet known what kind of mission the satellite is conducting," Yonhap quoted ministry spokesman Kim Min-seok as saying. "It usually takes two weeks to evaluate whether a satellite is successful. For the time being, it is working normally."
The rocket launch has been widely condemned as the North is prohibited by U.N. Security Council resolutions from further nuclear or missile tests after the country conducted two nuclear tests in 2006 and 2009. The North has said its latest test is for peaceful purposes.
Critics see the rocket firing as a cover by the North to test ballistic missiles capable of carrying nuclear weapons.
"If the North replaces the satellite with a nuclear war head, it could turn into an intercontinental ballistic missile," Yonhap quoted Kim as saying. He said since its nuclear tests, the North has been upgrading its atomic technology to conduct another test at some point.
Separately, NBC News, quoting U.S. officials, reported the North's satellite appeared to be "tumbling out of control" while orbiting the Earth. The officials were quoted as saying the object was some kind of space vehicle, but its precise purpose had not yet been determined.
NORAD, whose warnings systems monitored the North's launch, said: "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."
CNN, quoting an official, said the United States believes the North Koreans may not have full control of the satellite.
The report said experts also do not believe North Korea has a nuclear warhead small enough to fly on the kind of long-range missile it has used.
Although the object remained in orbit, the official told CNN the United States was looking into whether it is an operating satellite.
David Wright of the Union of Concern Scientists said the satellite itself may not be very sophisticated, as it had been shown to be a small box with solar panels and a simple camera with some basic communication devices, CNN reported. He said the value of the North Koream action may lie in the launch rather than in the object floating above the Earth.
The regime doesn't "really care so much what's in it," Wright said.
"I think this is very important to [North Korea's current leader] Kim Jong Un to build political legitimacy and bolster the spirits of his people," James Schoff, a North Korea specialist with the Carnegie Endowment for International Peace told CNN. "He is doing this despite the fact that he knows he is going to come into a lot of criticism in the region for it."
"If Kim Jong Un pulls off a successful long-range missile test, it's a very important signal saying that 'Yes, I, Kim Jong Un, have replaced the powerful generals,'" John Park at the Massachusetts Institute of Technology told CNN. "It shows that 'I have found the right balance and I am now in charge.' "
North Korea "could sell this technology to others, including Iran and Pakistan, who have been regular customers of North Korea's other missiles," the CNN reported, quoting analyst Victor Cha at the Center for Strategic and International Studies. "They still have other technological thresholds to cross [miniaturized warheads, re-entry vehicle], but this was undeniably a major one."