The Defense Ministry apparently doubts the credibility of information to be provided by a U.S. early-warning satellite in the event North Korea launches a rocket, sources said Friday.
"The 100 percent detection of the launch will be impossible, while prospective landing areas may be incorrect," a paper compiled in 1996 by the then Defense Agency noted.
While the defense authority revised part of it later, a senior ministry official said the basic understanding about the satellite's credibility has not changed since the paper was compiled.
The early-warning Defense Support Program satellite is expected to detect the launch of the North Korean rocket. The U.S. military will then compute its possible drop zone and timing based on the satellite data.
The data will be transferred to the Central Command Post of the Self-Defense Forces at the Defense Ministry and the Air Self-Defense Force's Air Defense Command, whose commander is authorized to direct the SDF to fire an interceptor at any part of the rocket if it appears to be falling toward Japan.
The information will also be relayed to the Maritime Self-Defense Force's Aegis-equipped destroyers, which, based on the data would launch the Standard Missile-3 interceptor missile to shoot down the rocket outside Earth's atmosphere.
The ministry paper says it is possible the early-warning satellite, whose infrared sensor would detect the rocket's heat exhaust, may fail to detect the launch if its boost stage it too brief.
Pyongyang says it plans to put an experimental communications satellite into orbit between Saturday and Wednesday.