Washington: A satellite launched by North Korea at the weekend has now stabilized in its orbit around the Earth in a step forward from a launch in 2012, a US official and a second source familiar with the matter said on Tuesday.
However, the satellite is not believed to be transmitting any data back to Earth, the second source said.
The satellite was initially tumbling in orbit but has now stabilized, making it more successful than a launch in 2012, which failed to achieve a stable orbit, said the first source, a US official who did not want to be identified by name.
"It's in a stable orbit now. They got the tumbling under control," the official said.
Martin O'Donnell, a spokesman with the US Strategic Command, said the satellite had been in roughly the same orbit since its launch on Sunday.
"If we see a dramatic change in altitude that could mean (the orbit) is going to decay," he said.
Satellites that cannot maintain their orbit eventually fall back into Earth's atmosphere and burn up.
North Korea, which carried out its fourth nuclear bomb test in January, says the Kwangmyongsong-4 (KMS-4) is an Earth observation satellite for peaceful purposes. It has been accused internationally of using the launch to try to enhance its ballistic missile capabilities.
Pyongyang said Sunday's launch was a "complete success" and that the satellite was making a polar orbit of Earth every 94 minutes.
The US government-backed Space-Track.org website shows the satellite in an orbit ranging from 473 km (296 miles) to 509 km (318 miles) and inclined 97.5 degrees north and south of the equator.
Charles Vick, senior technical analyst with GlobalSecurity.org website said the satellite appeared to be in stable orbit, but no transmissions had been detected from it.
"To date, I have not seen any visual or radio observation data on KMS-4," said Ted Molczan, a frequent contributor to the satellite-tracking website Heavens-Above.com.
John Schilling, an aerospace engineer and missile technology expert, said on Tuesday in a report on the 38north.org North Korea-monitoring website, it would be "an important step forward" for North Korea if the satellite could maintain a stable orientation, given North Korea's previous satellites tumbled out of control shortly after launch.
"If it can perform any sort of manoeuvre using an onboard propulsion system that would be a bigger step forward," he said, "(and) radio signals from the satellite would mark critical progress for North Korea in another area, particularly if they occur over a prolonged period and show signs of two-way communication."
