N. Korean Rocket Went Up 485km from Ground (in-depth details)
"First their Nuke Fails to go Critical and Now their Rockets fall Short.What a Grave Danger
They Turned out to be !"
(S. Korean Aegis ship) King Sejong tracked it ... fell short of orbit due to lack of speed. It is confirmed now that the long-range rocket(Taepodong-2) N. Korea launched on Apr. 5 reached the maximum altitude
of 485 km flying above Pacific. Intelligence sources said, "It is our understanding that, due to lack of propulsion,
it fell short of reaching earth orbit, and failed." The sources added that Aegis ship King Sejong was also able to track it and determine its maximum altitude." Altitude of 485km above surface is falling short of the nearest point of orbit N. Korea announced 'Kwangmyungsung 2'(its so-called satellite)has achieved.
After the launch, KCNA announced, " 'Kwangmyungsung 2' achieved an elliptic orbit with the nearest point of 490km from surface, and the farthest point of 1426km." Dr. Park Jung-joo, who heads a team of tracking N. Korean rocket at Korea Aerospace Research Institute, said, "We believe that N. Korean rocket did not reach sufficient speed to enter orbit. This is similar to what happened during Taepodong-1 launch in 1998."
In short, the rocket carrying the satellite came near to the lowest point of 490km above surface but did not have enough speed, and failed to enter the orbit. The speed required to enter the orbit is about 7.9km per second. Beyond 11.2km per second, the satellite would escape earth orbit.
However, the average speed of the N. Korea's first stage booster was only 1.19km per second. This is well below the average speed of 2.66km per second, reached by Taepondong-1