Nuclear Warhead Modernization
"In September 1981, China successfully delivered three satellites with one launch vehicle: two satellites were delivered in the nose cone and one was delivered during stage separation. This event may have been China's first foray into the area of MRV/MIRV development.
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A September 1999 National Intelligence Council document called "Foreign Missile Developments and Ballistic Missile Threat to the United States Through 2015" concluded that China has had the technical capability for MRVs for over two decades but apparently chose not to develop and deploy them. The report noted, however, that by leveraging current technologies China could develop a basic MRV or MIRV capability for its current missile force "in a few years." Specifically, the report said:
China has possessed dual-use multiple-satellite release/MIRV technology for 30 years. Why did China wait 30 years to deploy MIRVs? The most likely explanation is that China is serious about their "no first-use" policy. In delaying the deployment of MIRVs for 30 years, China has shown that its nuclear arsenal is strictly defensive in nature.
In reaction to military developments in the United States, China has started to deploy MIRVs. The first concern is stealth attack aircraft. China has a robust overlapping and interconnected air defense system, but the stealth attack jets may penetrate the current defenses. This places silo-based Chinese ICBMs and other retaliatory nuclear weapons at risk. The second problem is the relentless development and improvement of the American missile defense shield. China is no longer confident that it can inflict a sufficiently-painful retaliatory strike on the United States.
To address the problems of American stealth attack jets and missile defense system, China has built more mobile ICBM launchers (e.g. they are harder to find) and deployed MIRVs to overwhelm American missile defense. China's goal is to preserve its capability to inflict sufficient damage in a retaliatory strike to deter an American nuclear first-strike.
Here is an exciting video from Northrop Grumman on the ICBM Flight of a Minuteman III:
YouTube - ICBM Flight Minuteman III launch
If you have never seen a real video of incoming MIRVs, then you must watch this:
YouTube - Minuteman III Missile Launch - California to Kwajalein Atoll