The satellite that North Korea launched into space three years ago circles the earth every 95 minutes at an altitude of about 540 km (335 miles), its orbit decaying.
No signal has ever been detected from the crude-looking 100-kg (220-pound) 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 really testing a system to deliver nuclear weapons. The secretive state is already under international sanctions for its nuclear and missile tests.
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 program 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 in a 2013 analysis that the mission was a "low performance" event and "not a game changer."
"Nothing that has happened in the past years has changed my assessment," Schiller told Reuters this week, 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.