In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.

The system's interceptors are 60-foot-tall, three-stage rockets, each tipped with a 5-foot, 150-pound "kill vehicle." Once in space, the kill vehicles are designed to separate from their boost rockets and fly independently toward their targets, at speeds up to 4 miles per second. With the help of onboard navigation systems, the kill vehicles, which carry no explosives, are supposed to crash into and destroy enemy warheads using only kinetic energy. ||||| Breaking News Emails Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings. 
  
 / Updated By Courtney Kube, Andrew Rafferty and The Associated Press 
  
 WASHINGTON — The Pentagon successfully tested a U.S. long-range interceptor missile over the Pacific Ocean on Tuesday in an exercise aimed at helping gauge American readiness to counter a potential threat from North Korea. 
  
 During the test, the Pentagon's Missile Defense Agency launched an interceptor rocket from an underground silo at Vandenberg Air Force Base in California. The interceptor hit and destroyed an intercontinental-range missile fired from a test site on Kwajalein Atoll in the Pacific, the Pentagon announced. 
  
 U.S. Missile Defense Agency Director Vice Adm. Jim Syring called the test a "critical milestone" in a statement. 
  
 "This system is vitally important to the defense of our homeland, and this test demonstrates that we have a capable, credible deterrent against a very real threat. I am incredibly proud of the warfighters who executed this test and who operate this system every day," Syring said. 
  
 The U.S. military's test comes on the heels of North Korea's reported launch of a military projectile Monday morning that landed in Japan's maritime economic zone. It also comes amid heightened tensions between the U.S. and Pyongyang over North Korea's continued provocations under leader Kim Jong Un. 
  
 North Korea has said it is working on an ICBM, which could potentially hit the West Coast, and American officials are concerned about the possibility the North Koreans could miniaturize a warhead to put on an ICBM. 
  
 General John Hyten, the head of U.S. Strategic Command, has said Pyongyang already has ICBM capability, but still lacks a miniaturized warhead. 
  
 The $244 million test does not necessarily confirm that the American military is capable of defending itself against an intercontinental-range missile fired by North Korea. Pyongyang also is understood to be moving closer to the capability of putting a nuclear warhead on such a missile and could have developed decoys sophisticated enough to trick an interceptor into missing the real warhead. 
  
 President Donald Trump was briefed after a North Korean missile test earlier this month and the White House said in a statement at the time that "North Korea has been a flagrant menace for far too long." 
  
 During a recent visit to South Korea, Secretary of State Rex Tillerson said "the policy of strategic patience (with North Korea) has ended," and he added that military action could be on the table if North Korea elevates the threat of its weapons programs. 
  
 Before Tuesday, the most recent intercept test, in June 2014, also was successful, but the longer track record is spotty. Since the system was declared ready for potential combat use in 2004, only four of nine intercept attempts have been successful. 
  
 A Ground-based Midcourse Defense interceptor is launched from the Vandenberg Air Force Base, California on June 22, 2014. Michael Peterson / MDA 
  
 North Korea says its nuclear and missile programs are a defense against perceived U.S. military threats. 
  
 Laura Grego, senior scientist at the Union of Concerned Scientists, which has criticized the U.S. missile defense program, calls the interceptor an "advanced prototype," meaning it is not fully matured technologically even if it has been deployed and theoretically available for combat since 2004. 
  
 The interceptors are, in essence, the last line of U.S. defense against an attack by an intercontinental-range missile. 
  
 The Pentagon has other elements of missile defense that have shown to be more reliable, although they are designed to work against medium-range or shorter-range ballistic missiles. These include the Patriot missile, which numerous countries have purchased from the U.S., and the Terminal High-Altitude Area Defense, or THAAD, which the U.S. deployed this year to South Korea to defend against medium-range missiles from North Korea. ||||| WASHINGTON/VANDENBERG AIR FORCE BASE, Calif. (Reuters) - The U.S. military on Tuesday cheered a successful, first-ever missile defense test involving a simulated attack by an intercontinental ballistic missile, in a major milestone for a program meant to defend against a mounting North Korean threat. 
  
 The U.S. military fired an ICBM-type missile from the Kwajalein Atoll in the Marshall Islands toward the waters just south of Alaska. It then fired a missile to intercept it from Vandenberg Air Force Base in California. 
  
 Experts compare the job to hitting a bullet with another bullet and note the complexity is magnified by the enormous distances involved. 
  
 The Missile Defense Agency said it was the first live-fire test against a simulated ICBM for the Ground-based Midcourse Defense (GMD), managed by Boeing Co (BA.N), and hailed it as an “incredible accomplishment.” 
  
 “This system is vitally important to the defense of our homeland, and this test demonstrates that we have a capable, credible deterrent against a very real threat,” Vice Admiral Jim Syring, director of the agency, said in a statement. 
  
 A successful test was by no means guaranteed and the Pentagon sought to manage expectations earlier in the day, noting that the United States had multiple ways to try to shoot down a missile from North Korea. 
  
 “This is one element of a broader missile defense strategy that we can use to employ against potential threats,” Pentagon spokesman Captain Jeff Davis told reporters. 
  
 Slideshow (4 Images) 
  
 Prior to Tuesday’s launch, the GMD system had successfully hit its target in only nine of 17 tests since 1999. The last test was in 2014. 
  
 North Korea has dramatically ramped up missile tests over the past year in its effort to develop an ICBM that can strike the U.S. mainland. 
  
 The continental United States is around 9,000 km (5,500 miles) from North Korea. ICBMs have a minimum range of about 5,500 km (3,400 miles), but some are designed to travel 10,000 km (6,200 miles) or farther. 
  
 Riki Ellison, founder of the Missile Defense Advocacy Alliance, described the test as “vital” prior to launch. 
  
 “We are replicating our ability to defend the United States of America from North Korea, today,” Ellison said. 
  
 Failure could have deepened concern about a program that according to one estimate has so far cost more than $40 billion. Its success could translate into calls by Congress to speed development. 
  
 In the fiscal year 2018 budget proposal sent to Congress last week, the Pentagon requested $7.9 billion for the Missile Defense Agency, including about $1.5 billion for the GMD program. 
  
 A 2016 assessment released by the Pentagon’s weapons testing office in January said that U.S. ground-based interceptors meant to knock out any incoming ICBM still had low reliability, giving the system a limited capability of shielding the United States. |||||
US officials are calling Tuesday's successful test of the country's missile-defense system "an incredible accomplishment," the Los Angeles Times reports. A rocket fired from California intercepted and destroyed a target warhead fired toward Alaska from the other side of the Pacific Ocean. It was the first-ever test of the Ground-based Midcourse Defense system on a fast-moving "ICBM-range target." “This system is vitally important to the defense of our homeland, and this test demonstrates that we have a capable, credible deterrent,” the director of the Missile Defense Agency says. The $244 million test was the first since 2014, according to NBC News. It was conducted amid increased worry of a potential nuclear attack from North Korea. Despite Tuesday's success, there are many questions surrounding the viability of the GMD system during an actual attack. Only nine of the previous 17 tests since 1999 had been successful, Reuters reports. And that's with tests being scripted for success: daytime launches with personnel informed of the target's launch time, size, speed, and trajectory. It's also possible North Korea could use decoys to trick the system; the GMD's interceptor rockets haven't been tested against decoys. A Pentagon spokesperson says the GMD system is just one way the Pentagon has of shooting down a potential North Korean missile. The GMD system has cost US taxpayers more than $40 billion so far.