<b>Many previous experiments of the U.S. failed</b>
Before China's land-based intermediate-section anti-missile experiments, the U.S. is the only country carrying out the experiment. It is part of the U.S. Star Wars to acquire the land-based intermediate-section interception capabilities. But it is so technologically difficult that not until Oct.2, 1999 had the U.S. carried out the National Missile Defense System flight intercept experiment for the first time.
Then it conducted more than 10 experiments, but many ended up a failure. The blames lie with the loss of targets by interceptors, and the untimely separation of interceptor warheads with boosters.
The anti-missile R&D cycle is so long, the costs so high, and the techniques so complicated that it is impractical even for the U.S. to deploy it in large numbers at present. It is reported that the U.S. deploys only dozens of land-based interceptors at the Vandenberg Air Force Base in California and Fort Greeley in Alaska to shield itself from the ballistic missile threats from the so-called "Rogue states."
People on way home during Spring Festival travel rush