[ti:US Navy Cancels Development of High-Tech Railgun Weapon]
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[00:00.04]The U.S. Navy is halting development of a high-tech weapon
[00:05.84]designed to fire projectiles at up to seven times the speed of sound.
[00:14.28]The Navy spent more than 10 years developing the weapon,
[00:19.08]called an electromagnetic railgun.
[00:24.12]The cannon-like railgun uses electricity
[00:28.44]instead of chemical substances to fire projectiles.
[00:35.20]A report released earlier this year by the Congressional Research Service
[00:41.28]stated that the Navy had been developing the railgun
[00:46.24]as a firing weapon to support U.S. Marines operations.
[00:53.04]The report said the development also centered
[00:57.36]on possible use of the railgun as a missile defense system.
[01:04.24]The move to cancel railgun development
[01:08.04]comes as the U.S. Department of Defense turns its attention
[01:13.76]to the development of hypersonic missiles,
[01:17.80]The Associated Press reports.
[01:21.80]Hypersonic is a term that relates to speeds
[01:26.12]of more than five times the speed of sound,
[01:30.00]also known as Mach 5.
[01:33.24]In addition to flying at extremely high speeds,
[01:38.24]hypersonic weapons are designed to move in ways
[01:42.84]that make them difficult to find and destroy in flight.
[01:49.32]The U.S. military has been putting money into the development
[01:54.60]of hypersonic weapons in recent years in an effort to keep up
[02:00.32]with hypersonic military programs in China and Russia.
[02:06.60]Matthew Caris is a defense expert
[02:10.16]with the private advisory company Avascent Group.
[02:14.40]He told the AP that "the railgun is, for the moment, dead."
[02:22.00]The halt in railgun development, Caris said,
[02:26.32]suggests that the Navy saw difficulties
[02:30.16]in implementing the technology.
[02:34.00]In addition, the Navy likely recognized that hypersonic missiles
[02:39.80]have higher performing abilities than the railgun, he added.
[02:45.96]Lieutenant Courtney Callaghan is a Navy spokesperson.
[02:50.64]She told the AP that the Navy's decision will free up resources
[02:57.28]for hypersonic missiles, as well as lasers
[03:01.88]and other electronic warfare systems.
[03:06.52]The Navy spent about $500 million on research
[03:11.92]and development of the railgun, said Bryan Clark,
[03:16.96]a defense expert at the Hudson Institute.
[03:21.96]The railgun held the possibility of providing an effective weapon
[03:27.60]at a much lower cost than smart bombs and missiles.
[03:33.00]Using electricity, a railgun can fire a projectile
[03:38.60]at six or seven times the speed of sound,
[03:42.68]creating enough energy to destroy targets.
[03:47.00]But Clark said the program experienced a number of problems,
[03:53.08]including the limited range of the railgun in testing.
[03:59.36]In addition, its usefulness for missile defense
[04:03.28]was also limited by range and rate of fire, Clark added.
[04:10.76]Another big question was whether the gun could stay together
[04:15.84]during continuous firing, said defense analyst Norman Friedman.
[04:22.88]A normal gun can be fired about 600 times
[04:27.24]before the barrel has to be refurbished.
[04:31.20]But the barrel on tested railguns, Clark said,
[04:36.20]had to be replaced after about 12 to 24 shots were fired.
[04:42.52]A few years ago, the Navy was talking about putting the gun
[04:47.92]on the future USS Lyndon B. Johnson,
[04:52.00]the last of three stealthy destroyers.
[04:55.72]But now, the Navy is developing what it calls
[05:00.44]a "hypervelocity projectile,"
[05:03.80]which is designed to be fired from existing gun systems.
[05:09.52]I'm Bryan Lynn. 更多听力请访问21VOA.COM