SEOUL • The satellite that North Korea launched into space three years ago circles earth every 95 minutes at an altitude of about 540km, its orbit decaying.
No signal has ever been detected from the crude-looking 100kg hunk of black metal that the North said was mounted with cameras to take images and transmit them back to Pyongyang.
The North is planning another satellite launch next month, re-igniting fears that it is testing a system to deliver nuclear weapons. The secretive state is already under international sanctions for its nuclear and missile tests.
DIFFICULT TO ACQUIRE
It should be clear how important these capabilities are to the leadership because they are expensive and difficult to acquire.
MR DANIEL PINKSTON, who has studied the North's political and weapons strategy, saying Pyongyang's pursuit of long-range rocket technology should be taken seriously.
South Korean Foreign Minister Yun Byung Se said this month the North's plan to launch a new satellite, which could be timed around the 70th anniversary of its ruling party on Oct 10, would be a disguised missile test.
The United States has said such a launch could lead to more sanctions.
North Korea says its space programme is peaceful and any attempt to stop it is an attack on its sovereignty.
While many observers were impressed that Pyongyang managed to put an object into orbit in 2012, German aerospace engineer Markus Schiller said the mission was "not a game-changer".
"Nothing that has happened in the past years has changed my assessment," Mr Schiller told Reuters, despite further short-range missile launches by Pyongyang using existing technology.
"Most of these activities still seem to be more motivated by political reasons than by engineering ones," he said.
The satellite launched in December 2012 was propelled by North Korea's Unha-3, a home-grown three-stage rocket based on 1950s Soviet Scud missile technology, with advanced fuel used in its final stage. The design that made the Unha-3 suitable to launch a satellite makes it a poor vehicle to deliver weapons, said experts.
Still, the North's pursuit of long-range rocket technology should be taken seriously because of potential capabilities it might acquire in the future, said Mr Daniel Pinkston, a visiting fellow at Babes-Bolyai University in Romania, who has studied the North's political and weapons strategy.
"It should be clear how important these capabilities are to the leadership because they are expensive and difficult to acquire," he said.