Analysts have continued to question the real-world viability of missile shield efforts that have cost the United States at least $158 billion since the 1980s, Agence France-Presse reported.
Standard Missile 3 interceptors have struck their targets in more than 80 percent of their trials to date, but two respected academics in 2010 said such exercises are "carefully orchestrated ... to hide fundamental flaws." The technology is to serve as the backbone for developing U.S. ballistic missile defense operations in Europe.
Objects as simple as metal foil balloons are capable of distracting missile interceptors from their intended targets, AFP quoted specialists as saying.
"You can very easily create light decoys that will very easily fly with the warhead, just balloons for instance. And these are very hard to discriminate from the actual warhead," said Yousaf Butt, a physicist with the Monterey Institute of International Studies in California.
Officials have also admitted such distractive ploys could pose problems for the interceptors, which are now deployed on 26 U.S. warships.
The past two trials of the separate Ground-based Midcourse Defense system have ended in failure. The United States now has two ground-based interceptor sites in California and Alaska, and some GOP lawmakers have called for a third on the U.S. East Coast.
The overall antimissile system appears capable of guarding the United States against "a limited attack from both North Korea and Iran today and in the near future," Lt. Gen. Richard Formica, head of the Army Space and Missile Defense Command, said to legislators in May. The United States is not today within reach of missiles from either country.
U.S. missile shield operations have been less impacted by federal financial troubles than other Defense Department activities, according to AFP. The Obama administration has requested $9.2 billion for the work in the next budget year.