[ti:Experts: North Korea Lacks Missile Technology to Reach Mainland US]
[by:www.21voa.com]
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[00:00.20]North Korea still lacks the necessary technology to send a nuclear weapon
[00:07.32]all the way to the United States mainland, say experts.
[00:12.40]But the same experts admit that North Korea's test
[00:17.84]of an intercontinental ballistic missile,
[00:21.08]or ICBM, last week marked an improvement in its military program.
[00:28.14]The ICBM that North Korea tested on July 28
[00:33.46]was the second long-distance rocket it launched in the month of July.
[00:39.68]The missile tested is called the Hwasong-14.
[00:44.64]Defense officials in the U.S. and South Korea said the military launched it
[00:50.88]from the Mupyong-ni arms factory in the country's north.
[00:56.80]The missile traveled a distance of about 1,000 kilometers.
[01:02.52]But it reached an altitude of about 3,700 kilometers.
[01:08.84]It was in flight for about 45 minutes before falling into the sea.
[01:15.32]The missile crashed into the waters 175 kilometers from Hokkaido,
[01:21.64]Japan's second largest island.
[01:25.24]Jonathan McDowell is an astrophysicist at the Harvard-Smithsonian Center for Astrophysics.
[01:33.16]He told VOA's Korean service that it appears North Korea has a fully operational ICBM.
[01:41.96]He said, "It seems to have worked as designed,
[01:45.32]and so that is a milestone in their missile development."
[01:50.16]McDowell noted that the military did not launch the rocket into the atmosphere
[01:55.53]in a normal way in order to travel the greatest distance.
[02:00.40]If it had, the rocket's weapons system could have traveled further.
[02:06.20]An earlier test on July 4 showed the furthest the Hwasong-14
[02:12.03]could reach was between about 7,000 and 8,000 kilometers.
[02:18.32]This means it would have been able to reach Alaska.
[02:21.97]Experts continue to debate how North Korea was able to improve the missile's performance.
[02:29.16]McDowell suggests that higher-powered engines
[02:33.61]driving the rocket during its second stage could have given it "a bit more push."
[02:39.04]The technology that directs missiles back to earth
[02:42.76]after launching has been one of the biggest problems for North Korea.
[02:48.64]And many experts doubt that North Korea's military has perfected that technology.
[02:55.96]The weapons systems must be able to survive the extreme heat
[03:01.00]and pressure generated from traveling through the atmosphere.
[03:05.92]If not, ICBMs armed with nuclear weapons will not reach their targets.
[03:12.56]There are additional doubts about North Korea's missile technology.
[03:18.96]They come from video by the Japanese public news agency NHK.
[03:25.80]The video showed the Hwasong-14 possibly falling apart
[03:30.88]as it landed in the waters off Hokkaido.
[03:34.88]Michael Elleman is a senior fellow for missile defense
[03:39.16]at The International Institute for Strategic Studies.
[03:43.68]He said that small, bright objects appeared to be falling off the missile as it returned to earth.
[03:52.20]This could be showing that the missile was breaking apart too soon.
[03:57.28]Other experts, however, have suggested that the missile breaking apart
[04:02.88]may have been due to the steep angle of its flight path.
[04:07.24]The steep angle would have increased its speed and also its surface heat.
[04:13.01]Elleman wrote on the website 38 North, which reports about North Korea:
[04:20.20]"A reasonable conclusion, based on the video evidence,
[04:24.16]is that the Hwasong-14's re-entry vehicle did not survive during its second test."
[04:31.92]He wrote that North Korea has more work to do before the country's leader
[04:36.56]Kim Jong Un has a missile able to strike the American mainland.
[04:41.84]But McDowell notes that it will only take the country a few more years
[04:46.44]to reach the level of technology it desires.
[04:50.20]I'm Jill Robbins.
[04:52.00]And I'm Pete Musto. 更多听力请访问21VOA.COM