The five-day window for North Korea's rocket launch opened Thursday, meaning liftoff could come any morning between now and Monday, weather and technology permitting. The U.S. and others have condemned the launch as a test of missile technology. North Korea claims it is merely seeking to put a satellite in orbit. Experts say it is probably a mix of both, since the technologies are nearly identical. Here are some things to watch for once the countdown begins.
GETTING INTO ORBIT
The Unha-3 rocket has three stages, or parts. If all goes well, the first will burn out and fall in waters off the west coast of South Korea in about 2 minutes. The second will separate 4 to 6 minutes after the launch, then splash down in the Pacific off the northern Philippines. The third will burn up in the atmosphere after boosting the satellite into orbit.
All this will take 10 minutes. The satellite will then enter a near-polar, sun-synchronous orbit, meaning it will pass over the same point on the Earth at about the same time each day. The 500-kilometer (300-mile) altitude announced by the North is considered a low Earth orbit, which is where most artificial satellites go.
Professional and amateur satellite watchers question North Korea's calculations. They infer from data provided by Pyongyang that the probe will not be able to reach its orbit without conducting difficult navigational maneuvers very soon after liftoff. One expert says the rocket will skirt China's east coast near Shanghai, fly over Taiwan and shed its second stage into the sea, 50 kilometers (30 miles) off the northern Philippines.
Japan and South Korea say they will shoot down the rocket in the unlikely event it veers off course and heads toward their territory.
The minibar refrigerator-sized satellite is covered with solar panels and golden foil to protect its instruments. One meter (three feet) tall and weighing 100 kilograms (220 pounds), the Bright Shining Star 3 is designed to monitor weather, natural disasters and agriculture patterns. Experts say the satellite and its predecessors, Bright Shining Stars 1 and 2, were probably developed with China's help. It is unlikely the latest version could effectively multitask, since it is so small and North Korea has no demonstrated track record with simpler missions.
ODES FROM SPACE
Pyongyang says the satellite will broadcast martial music praising North Korea's founder, Kim Il Sung. It says Bright Shining Stars 1 and 2, launched in 1998 and 2009, did the same. But no broadcasts were ever detected, and neither probe is believed to have reached orbit.
If the broadcasts on the UHF and X-bands are successful, the first independent confirmation could come from western Australia, which might pick them up within 20 minutes. The west coast of South America would be next, followed by the U.S. east coast. North Korea would not likely hear them until as much as 12 hours later.