Since 2014 China has conducted six tests of a maneuverable gliding warhead for ballistic missiles. Five of the six tests were successful and this “hypersonic glide vehicle” is officially known as the DF-ZF. In effect a hypersonic glide vehicle is a warhead that can glide rather than simply plunging back to earth and is maneuverable enough to hit small moving targets in space or down on the surface. The DF-ZF was initially developed as China sought to perfect a version of the DF-21 ballistic missile that could hit moving warships at sea. DF-21 is a 15 ton, two stage, solid fuel missile that is 10.7 meters (35 feet) long and 140cm (4.6 feet) in diameter. Range varies (from 1,700-3,000 kilometers) depending on model and type of warhead. With the DF-ZF warhead DF-21 range is extended fifty percent (to about 3,000 kilometers). Used on a larger ballistic missile like the DF-31 or DF-41 and max range becomes about 12,000 kilometers. The DF-21D (the carrier killer version) missile using the DF-ZF is also more difficult for anti-missile missiles to hit and can also be used against low orbit satellites.
Until 2013 there was no evidence that the complete DF-21D system had been tested. Then satellite photos showed a 200 meter long white rectangle in the Gobi Desert (in Western China) with two large craters in it. This would appear to be a “target” for testing the DF-21D, and two of the inert practice warheads appear to have hit the target. American carriers are over 300 meters long, although the smaller carriers (amphibious ships with helicopter decks) are closer to 200 meters long. It appeared China was planning on using the DF-21D against smaller warships, or perhaps they just wanted to see exactly how accurate the missile could be. Then in 2014 an even more maneuverable and gliding version of the carrier killer warhead appeared in the form of the hypersonic glide vehicle.
Russia and the United States have also developed this technology but neither has deployed it in the form the Chinese appear to be using. The original work in this area was by the Germans during World War II. The U.S. and Russia both investigated the concept more during the Cold War but never deployed anything. In the 1990s the United States proposed reviving work on hypersonic glide vehicle for its Prompt Global Strike. This would put hypersonic glide vehicle warheads, using high-explosive and not nuclear explosives, on ICBMs producing a very expensive weapon that could hit a target anywhere on earth in less than an hour of the order being given. Many believe the Chinese DF-ZF will mainly be used as an anti-satellite weapon. In any event the United States successfully tested its version of the hypersonic glide vehicle in 2011 but with the defense budget shrinking at that point, the project was halted. This was also prompted by a 2014 hypersonic glide vehicle test that failed. Meanwhile Russia has resumed 2014 hypersonic glide vehicle development in 2013 but financial problems are preventing much progress.