Action/Reaction: U.S. Space Weaponization and China

Chinese officials have expressed a growing concern that U.S. space and missile defense plans will stimulate a costly and destabilizing arms race. In particular, the prevailing view in Beijing is that the United States seeks to neutralize China’s strategic nuclear deterrent, freeing itself to intervene in China’s affairs and undermining Beijing’s efforts to prod Taiwan to reunify. If U.S. plans are left unchecked, therefore, Beijing may feel compelled to respond by introducing its own space weapons.

Beijing, however, would prefer to avoid this outcome. Chinese officials argue that weaponizing space is in no state’s interest, while continued peaceful exploitation redounds to the benefit of all states. Rather than battling over space, China wants countries to craft an international ban on space weaponization.

U.S. Moves Toward Space Weaponization

China ’s concerns are prompted by evidence that U.S. moves toward space weaponization are gaining momentum. In January 2001, a congressionally mandated space commission headed by Donald Rumsfeld, who is now secretary of defense, recommended that “the U.S. government should vigorously pursue the capabilities called for in the National Space Policy to ensure that the president will have the option to deploy weapons in space to deter threats to, and, if necessary, defend against attacks on U.S. interests.”[1]

Moreover, the U.S. withdrawal from the Anti-Ballistic Missile Treaty in 2002 has given the United States a free hand to move forward with missile defenses, and space-based missile defenses are envisioned as part of the U.S. mix. In the clearest official sign yet of support for space weaponization, last year the U.S. Air Force publicized its vision of how “counterspace operations” could help achieve and maintain “space superiority,” the “freedom to attack as well as the freedom from attack” in space.[2]

Already the United States is pursuing a number of military systems[3] that could be used to attack targets in space from Earth or targets on Earth from space. To China, current U.S. deployment of a Ground-Based Midcourse Missile Defense system represents an intentional first step toward space weaponization.[4] China experts argue that the interceptors of the system based in Alaska and California could be used to attack satellites.[5]

After all, such systems could be easily adapted to target satellites, which are more fragile and more predictable than ballistic missile warheads. If the United States is determined to ensure “space dominance,” it would first want to use such weapons to negate an adversary’s satellites.

Beijing is even more concerned about U.S. plans for a robust, layered missile defense system. Such a system would provide the capability to engage ballistic missiles in all phases of flight: soon after they are launched, at the height of their trajectory, and as they descend. These are known as the boost, midcourse, and terminal phases, respectively. In particular, China is concerned about interceptors and other defenses that the United States would like to position in space.

The Pentagon announced in December 2002 that the United States would continue the “development and testing of space-based defenses, specifically space-based kinetic energy [hit-to-kill] interceptors and advanced target tracking satellites.” The Pentagon has indicated that a Space-Based Interceptor Test Bed, intended to develop and test plans for a lightweight space-based kinetic kill interceptor, is expected to conduct its first experiment in 2012.

Within the next year, the Pentagon expects to launch into low-Earth orbit (LEO) its first Near Field Infrared Experiment (NFIRE) satellite, designed to gather information on ballistic missiles during the first few minutes of their flight. Although the NFIRE at this point is only charged with gathering information, the Missile Defense Agency (MDA) had originally planned to include a kill vehicle in the NFIRE’s payload and could presumably change its mind again.

Moreover, research on a Space-Based Laser (SBL) had been conducted for some time for boost-phase missile defense. Although MDA cancelled the SBL program in 2002, a number of directed-energy initiatives can still be found in various other programs. The possibility of reviving the SBL program in MDA is still there.

Similarly, other space programs could be turned into weapons. For instance, the Air Force has a research project on small satellites, the Experimental Satellite System (XSS), that seeks to use such satellites to conduct “proximity operations,” maneuvers around other satellites. Some have said the XSS satellites could be used to inspect, service, or attack other satellites.[6] The Air Force in April launched the satellite XSS-11 as part of the series. In addition, the Air Force has considered using weapons for prompt global force projection through space, such as the common aero vehicle and Hypervelocity Rod Bundles (often termed “rods from God”).[7] Such space-based global strike capability would allow the United States to target and strike any point on earth in less than 90 minutes with complete surprise and provide the capability for flexible strikes for different types of targets, such as hard and deeply buried targets or mobile targets.

Space Weapons and China’s Security

The United States clearly has legitimate concerns about its space assets, given that U.S. military operations and the U.S. economy are increasingly dependent on them. Satellites are inherently vulnerable to attacks from many different sources, including ground-based missiles, lasers, and radiation from a high-altitude nuclear explosion. However, it does not mean that the United States currently faces credible threats from states that might exploit those vulnerabilities.[8] Most analysts believe no country seriously threatens U.S. space assets.[9]

Only the United States and, in the Cold War era, the Soviet Union have explored, tested, and developed space weapons; Russia placed a moratorium on its program in the 1980s. To be sure, a number of countries, including China, are capable of attacking U.S. satellites with nuclear weapons, but such an attack would be foolhardy, as it would almost certainly be met by a deadly U.S. response. Moreover, as many experts point out, space-based weapons cannot protect satellites because these weapons are nearly as vulnerable to attack as the satellites themselves.[10] No wonder that many countries, including China and Russia, have sought multilateral negotiations on the prevention of space weaponization.

A Loss of Strategic Nuclear Deterrent Capability

Many Chinese officials assume that China is the real target for U.S. missile defense and space planning. From Beijing’s perspective, it is inconceivable that Washington would expend such massive resources on a system that would be purely defensive and aimed only at “rogue” states. As seen by Chinese leaders, China’s own small strategic nuclear arsenal appears to be a much more plausible target for U.S. missile defenses.[11]

Chinese experts are concerned that even a limited missile defense system could neutralize China’s fewer than two dozen single-warhead ICBMs that are capable of reaching the United States. “It is evident that the U.S. [national missile defense] will seriously undermine the effectiveness of China’s limited nuclear capability from the first day of its deployment,” said Ambassador Sha Zukang, the former director-general of the Department of Arms Control and Disarmament at the Chinese Ministry of Foreign Affairs. “This cannot but cause grave concerns to China,” he said.[12] Some Chinese fear that, whether or not the U.S. missile defenses are as effective as planned, U.S. decision-makers could act rashly and risk a disarming first strike once the system is operational.

Beijing is particularly concerned about the refusal of the United States, unlike China, to declare a no-first-use nuclear policy. The Bush administration’s 2001 Nuclear Posture Review (NPR) feeds these anxieties. The NPR specifically mentions the possibility of using nuclear weapons during a conflict in the Taiwan Strait and the possible use of tactical nuclear weapons. The Pentagon’s draft Doctrine on Joint Nuclear Operations would maintain an aggressive nuclear posture including the possible use of nuclear weapons to pre-empt an adversary’s attack with weapons of mass destruction and increasing the role of such weapons in regional (theater) nuclear operations.[13] Thus, some experts fret that the U.S. policy of possible first use of nuclear weapons, in combination with its missiles defenses and a lowered nuclear threshold, could encourage Washington to resort to the threat or use of nuclear weapons against China over Taiwan.

U.S. plans for global force projection would pose another threat to China. Some proposed space weapons such as common aero vehicles would be used to target hard and deeply buried as well as mobile targets. Such weapons would pose a major threat to the nuclear arsenal of mobile ICBMs that China is in the process of developing.

Consequently, China worries that the combination of future U.S. space weapons and its missile defense system could subject China to political or strategic blackmail. Such systems would give the United States much more freedom to intervene in China’s affairs, including undermining China’s efforts at reunification with Taiwan. This concern is enhanced by U.S. moves in recent years to boost cooperation in research and development of advanced theater missile defense with Japan and potentially with Taiwan.

Arms Competition in Space and On Earth

One major Chinese concern about U.S. space weaponization plans, as addressed frequently in statements at the UN Conference on Disarmament (CD), is that the deployment of space weapons “will disrupt strategic balance and stability, undermine international and national security and do harm to the existing arms control instruments, in particular those related to nuclear weapons and missiles, thus triggering new arms races.”[14]

Because space weapons are at once threatening and vulnerable, it is reasonable to assume that other countries would attempt to block such a move by political and, if necessary, military means. One possible response, for example, would be the development of anti-satellite weapons to target space-based weapon systems. It is widely believed that space weapons and sensor satellites would themselves become prime high-value targets and the most vulnerable elements for defense suppression attacks.[15] It is reasonable to believe that other countries could resort to a number of low-cost and relatively low-technology anti-satellite devices to counter those critical and vulnerable U.S. space-based weapons. Eventually, China fears that the U.S. space weaponization plan would lead to an arms race in outer space and turn outer space into a battlefield.

Moreover, space weaponization would seriously disrupt the arms control and disarmament process. The initiation of U.S. space-based missile defenses would likely cause Russia as well as the United States (in response to Russia) to make smaller reductions in their nuclear arsenals. China would likely be forced to build more warheads to maintain its nuclear deterrent, which could in turn encourage India and then Pakistan to follow suit. Also, Russia has threatened to respond to any country’s deployment of space weapons. Failure to proceed with the nuclear disarmament process would also further undermine the already fragile nuclear nonproliferation regime. As Ambassador Hu Xiaodi warned in 2001, “With lethal weapons flying overhead in orbit and disrupting global strategic stability, why should people eliminate [weapons of mass destruction] or missiles on the ground? This cannot but do harm to global peace, security and stability, hence be detrimental to the fundamental interests of all states.”

Limitations on China’s Civilian And Commercial Space Activities

As addressed in a Chinese proposal to hold talks on a proposed agreement to prevent an arms race in outer space (PAROS) at the CD in 2002, Beijing argues that “outer space is the common heritage of mankind and plays an ever-increasing role in its future development.” In its 2004 defense White Paper, Beijing further emphasized that “ China hopes that the international community would take action as soon as possible to conclude an international legal instrument on preventing the weaponization of and arms race in outer space through negotiations, to ensure the peaceful use of outer space.”[16]

China is particularly concerned that space weaponization could limit its civilian and commercial space activities and negatively affect its economic development. Today, China has various operational civilian satellites in space, a family of launchers, a modern space-launch complex, and a growing list of customers in the international satellite-launch market.[17] Since launching its first satellite in 1970, China has made steady progress both in launch vehicle design and in other areas of space technology development for civilian and commercial purposes. China has developed manned spacecraft and a high-reliability launching vehicle. Between November 1999 and December 2002, China launched four unmanned experimental Shenzhou (Magic Ship) spacecraft. In October 2003, China successfully launched the Shenzhou-5 manned spaceship and, in October 2005, the Shenzhou-6 manned spaceship. China is now planning to explore the moon with unmanned spacecraft. The U.S. pursuit of space control would threaten China’s civilian and commercial space activities and perhaps even deny China access to space.

Space Debris

China also fears the increasing population of space debris. Such debris, resulting from 50 years of space activity, already poses a considerable hazard to spacecraft. Under U.S. space weaponization plans, this crowding problem could worsen as a large number of space weapons could be deployed in LEO. The launching and testing of weapons would also increase space debris. Moreover, deploying space-based weapons in the increasingly crowded realm of LEO would leave less room for civilian systems.

Those problems would also occur during periods of peace. If a number of satellites were to be destroyed during the course of a war, some scientists warn, they would create so much debris that it would prevent future satellites from being stationed in space and generally limit space access. Indeed, pointing to the debris problem, Chinese scientists and officials have said that space weaponization should be considered an environmental threat as well as a security problem.

China’s Options

Historically, China’s stated purpose for developing nuclear weapons was to guard itself against nuclear blackmail. Beijing’s official statements do not discuss potential responses to U.S. space weaponization, but many Chinese officials and scholars argue that China must ensure that U.S. efforts do not negate the effectiveness of its nuclear deterrent. As one Chinese official stated:

China is not in a position to conduct an arms race with the United States and it does not intend to do so, particularly in the field of missile defense. However, China will not sit idly by and watch its strategic interests being jeopardized without taking necessary measures. It is quite possible and natural for China to review its military doctrine and a series of policies on the relationship with big powers, Taiwan issues, arms control and nonproliferation, etc.

Certainly, the best option for China is to reach an arms control agreement to prevent space weaponization, as it is advocating now. However, if this effort fails and if what China perceives as its legitimate security concerns are ignored, China would very likely develop other responses to neutralize the perceived threat. Because it is not clear what type of missile defense system the United States will finally deploy or whether the U.S. space control plans will be implemented, it is difficult to identify conclusively China’s specific countermeasures. Yet, there are certain options that it would be likely to consider. It should be noted that these discussions are based on China’s capabilities and do not characterize China’s intentions.

Build More ICBMs

One of China’s simplest options would be to build more ICBMs. Until now, although China has the smallest declared nuclear arsenal of the five nuclear-weapon states, its modernization efforts have been aimed more at quality than quantity. The current effort focuses mainly on enhancing the survivability of its strategic nuclear force through greater mobility. By contrast, the size of the force has grown quite modestly. Absent U.S. missile defense plans, China might be expected to build no more than 50 ICBMs by 2015.

China’s plans could change significantly were the United States to deploy a more comprehensive or more operationally successful missile defense. To maintain a credible minimum retaliatory capability, the size and quality of China’s nuclear arsenal would have to shift.

Predicting an exact response is difficult without knowing the specifications of a U.S. missile defense system, including the numbers of interceptors and the firing doctrine. However, one could project the potential changes in size of China’s nuclear arsenal based on a few simple assumptions. For example, China might need about 100-300 ICBMs to defeat the current U.S. system if that system employed 100-250 interceptors. Clearly, China would need even more warheads to penetrate a layered ballistic missile defense system.

Missile Defense Countermeasures

China could also employ a number of technically feasible and cost-effective measures so that its warheads would stand a strong chance of penetrating a missile defense system.

A number of countermeasures could defeat a midcourse missile defense system like the current one in Alaska.[18] For example, each ICBM could be deployed with decoys. Conversely, China might also disguise the warhead as a decoy by enclosing it in a radar-reflecting balloon, covering it with a shroud, hiding it in a cloud of chaff, or using electronic or infrared jamming measures. Beijing has already demonstrated that it can use decoys and similar capabilities. It has been reported that China has already made some missile flight tests with penetration aids, such as the 1999 flight test of China’s new DF-31 ICBM.

Similarly, a number of measures could be developed to counter a space-based interceptor.[19] One countermeasure would be to develop technology to boost rockets faster, rendering important boost-phase defenses impotent. China has already made steps in this direction by developing solid-fuel ICBMs that burn faster than its previous liquid-fueled missiles.

If the spaced-based laser were to be revived, specific countermeasures could be developed. The countermeasures could include rotating the missile to distribute the laser energy over a wide area, thus preventing the missile from being damaged, or protecting the vulnerable parts of the ICBM with reflective or ablative coatings.[20] Moreover, the attacker could simultaneously launch several ICBMs or an ICBM with some theater or tactical ballistic missiles used as decoys from a compact area to overwhelm space-based weapon systems.

Anti-Satellite Weapons

Moreover, it is reasonable to believe that China could resort to asymmetric methods, such as anti-satellite weapons, to counter critical and vulnerable space-based components in LEO such as space-based interceptors, a space-based laser, or space-based tracking satellites.

China’s best anti-satellite pick might be small, ground-launched kinetic-kill vehicles, which can be used to destroy their target by colliding with it at extremely high velocity. Such weapons are relatively cheap and technically easy and should be well within China’s grasp. These vehicles could reach a satellite in LEO; if mated with a larger booster, they might be capable of reaching higher orbits. Another possible anti-satellite weapon would be a space mine armed with conventional charges. China could also resort to using missiles to deliver a cloud of shrapnel to a particular spot in LEO at a precise time and destroy a space-based interceptor or space-launch satellite as it arrives there.

Countries such as China that have the ability to place objects in orbit or lift them to geosynchronous altitude can also track objects closely in space. Beijing should thus have the ability to develop weapons that could attack satellites either in low-Earth or geosynchronous orbit.

Still, it should be noted that, although China has some technology capabilities that could be used potentially as anti-satellite weapons, it does not mean China has already developed them or has the intention to do so. Several recent editions of the Pentagon’s Chinese military power report claim China is developing and intends to deploy such weapons, including a direct-ascent system, ground-based laser anti-satellite weapons, and microsatellites for weapons purposes.

However, there is no evidence to back up these claims, and China would have been foolish to pursue such weapons, given the diplomatic damage it would have caused amid its two-decade-long ardent support for preventing the weaponization of outer space. However, if the United States moves forward with space-based weapons, there would far less diplomatic cost to doing so.

Reconsidering China’s Arms Control Participation

U.S.-led space weaponization might also lead China to reconsider its participation in some multilateral nuclear arms control treaties. As Ambassador Sha Zukang stated, “ China cannot afford to sit on its hands without taking the necessary measures while its strategic interests are being jeopardized. China, inter alia, may be forced to review the arms control and nonproliferation policies it has adopted since the end of the Cold War in light of new developments in the international situation.”

For example, a need for more weapons would mean a need for more plutonium and highly enriched uranium (HEU) to fuel those weapons and thus likely hurt China’s support for a proposed fissile material cutoff treaty (FMCT). My conservative estimate is that China’s existing stockpile contains about two tons of weapons-grade HEU and one ton of separated plutonium, which could fuel approximately 300 warheads. Thus, this existing stockpile would be sufficient for its current modernization program. However, if China were driven to expand its ICBM arsenal significantly because of missile defense deployments, it might feel compelled to be able to retain the option to restart production of fissile materials and be unwilling to join an FMCT.

Indeed, China has linked these issues since 2000, contending that the space weaponization issue “is just as important as fissile material cut-off, if not more.” For several years, China demanded that FMCT and PAROS talks be launched at the same time. But the United States opposed any negotiations on the outer space issue, and the disagreement prevented the CD from continuing any arms control negotiations for several years. Aiming to break the deadlock at the CD and to promote the international arms control and disarmament process, China dropped in 2003 its linkage between an FMCT and the PAROS negotiations and agreed to a negotiation of an FMCT. China is still seeking PAROS talks, however.

A U.S. move into space could also lead China to reconsider its support for the Comprehensive Test Ban Treaty (CTBT). China signed the CTBT in 1996 and has not yet ratified it, partly because it was rejected by the U.S. Senate in 1999. However, U.S. missile defense and space weaponization plans would make Chinese ratification even more difficult. China may feel the need for additional nuclear tests if the need to counter a missile defense drives Beijing to develop new warheads that include decoys or maneuverable warheads. Already, China faces concerns from some experts who think that the CTBT will put more direct constraints on China’s nuclear weapons program than on the weapons programs of other states.

Conclusion: A Ban on Space Weaponization

Given the possibility of effective and cheap countermeasures, it seems foolish to many Chinese that the United States would bother to deploy highly expensive space-based weapons or anti-satellite technologies. If Washington really wants to reduce the potential vulnerability of its space assets, there are a number ways to improve space security, including technical approaches, rules of the road, and arms control agreements. By contrast, weaponizing space can only further worsen space security. As Hu emphasized recently, “[F]or ensuring security in outer space, political and legal approaches…can still be effective, while resorting to force and the development of space weapons will only be counter-productive.”

In China’s view, the most effective way to secure space assets would be to agree on a ban on space weaponization. As its working paper to the CD emphasizes, “Only a treaty-based prohibition of the deployment of weapons in outer space and the prevention of the threat or use of force against outer space objects can eliminate the emerging threat of an arms race in outer space and ensure the security for outer space assets of all countries which is an essential condition for the maintenance of world peace.”

China’s stance on banning weapons in outer space has been consistent since 1985 when it first introduced a working paper to the CD on its position on space weapons. China’s most recent working paper on the issue, introduced in June 2002, emphasizes three basic obligations:

Not to place in orbit around the Earth any objects carrying any kinds of weapons, not to install such weapons on celestial bodies, or not to station such weapons in outer space in any other manner.

Not to resort to the threat or use of force against outer space objects.

Not to assist or encourage other states, groups of states, and international organizations to participate in activities prohibited by this treaty.

In order to advance the CD work on the PAROS issue, in August 2004 China together with Russia prepared two nonpapers on the issues of “verification aspects of PAROS” and “existing international legal instruments and the prevention of the weaponization of outer space” and in June 2005 one more nonpaper on the issue of “definition issues regarding legal instruments on the prevention of weaponization of outer space.”

The nonpaper on verification offers a view that a verification regime in a future outer space treaty will be highly complicated and difficult and will encounter great technological and financial challenges. It does not rule out a verification protocol in the future but seeks to sidestep this from becoming an obstacle to getting started on PAROS negotiations. So, it urges that an outer space legal instrument be formulated without verification procedures for the time being. It cites the case of the 1967 Outer Space Treaty to show that, even without a verification mechanism, a treaty can be effective and play an important role.

The Chinese initiative has considerable support. In recent years, the UN General Assembly has adopted by overwhelming majorities resolutions calling for the CD to start a negotiation on the Prevention of an Arms Race in Outer Space agreement. These votes do not appear to have impressed the United States. John Bolton, then-U.S. undersecretary of state for arms control and nonproliferation, told the CD in 2002 that “the current international regime regulating the use of space meets all our purposes. We see no need for new agreements.”

Yet, Bolton is clearly in error. No existing treaties effectively prevent the testing, deployment, and use of weapons other than those of mass destruction in outer space. In addition, none of these instruments covers the threat or use of force from Earth, including land, sea, and atmosphere, against objects in outer space. If the history of proliferation tells us anything, it is that banning the testing and deployment of weapons from the outset is much more effective than attempting disarmament and nonproliferation after the fact.

Hui Zhang is a research associate in the Project on Managing the Atom at Harvard University’s John F. Kennedy School of Government. The views expressed here are the author’s alone.

ENDNOTES

1. “Report to the Commission to Assess United States National Security Space Management and Organization,” Washington, DC, January 11, 2001.

2. U.S. Air Force, “Counterspace Operations,” Air Force Doctrine Document 2-2.1, August 2, 2004.

3. The scope of space weaponry, generally accepted by many Chinese, includes not only weapons stationed in outer space but also weapons anywhere that target objects in outer space. See Liu Huaqiu, ed., Arms Control and Disarmament Handbook ( Beijing: National Defense Industry, 2000).

4. Fu Zhigang, “Concerns and Responses: A Chinese Perspective on NMD/TMD,” Consultation on NATO Nuclear Policy, National Missile Defense & Alternative Security Arrangements, Ottawa, September 28-30, 2001.

5. Qiu Yong, “Analysis on the ASAT Capability of the GMD Interceptor,” Presentation at the 16th International Summer Symposium on Science and World Affairs, Beijing, July 17-25, 2004.

6. Jeffrey Lewis, “Programs to Watch,” Arms Control Today, November 2004.

7. Bob Preston et al., Space Weapons, Earth Wars, MR-1209 ( Washington, DC: RAND, June 2002); Bruce DeBlois et al., “Star-Crosses,” IEEE Spectrum, May 2005.

8. See Federation of American Scientists, “Ensuring America’s Space Security: Report of the FAS Panel on Weapons in Space,” October 2004.

9. See Jeffrey Lewis, “False Alarm on Foreign Capabilities,” Arms Control Today, November 2004.

10. See David Wright et al., The Physics of Space Security: A Reference Manual ( Cambridge, MA: American Academy of Arts and Sciences, May 2005); Bruce DeBlois et al., “Space Weapons: Crossing the U.S. Rubicon,” International Security, vol. 29, no. 2 (Fall 2004).

11. Sha Zukang, “U.S. Missile Defense Plans: China’s View,” Disarmament Diplomacy, no. 43, 2000.

12. Sha Zukang, “The Impact of the U.S. Missile Defense Programme on the Global Security Structure,” CPAPD/ORG Joint Seminar on Missile Defense and the Future of the ABM Treaty, Beijing, March 13-15, 2000.

13. Hans Kristensen, “The Roles of U.S. Nuclear Weapons: New Doctrine Falls Short of Bush Pledge,” Arms Control Today, September 2005.

14. Statement by Ambassador Hu Xiaodi at the Plenary of the 2nd Part of the 2005 Session of the Conference on Disarmament, June 30, 2005.

15. See Ashton Carter, “The Relationship of ASAT and BMD Systems,” in Weapons in Space, (New York: W.W. Norton, 1986).

16. Information Office of the PRC State Council, “White Paper on China’s National Defense in 2004,” December 27, 2004.

17. Information Office of the PRC State Council, “White Paper on China’s Space Activities,” November 22, 2000.

18. Andrew Sessler et al., “Countermeasures: A Technical Evaluation of the Operational Effectiveness of the Planned U.S. National Missile Defense System,” April 2000; Huang Hai, “Technical Analysis of National Missile Defense and Its Effects on World Arms Control,” Presentation at the 13th International Summer Symposium on Science and World Affairs, Berlin, July 21-30, 2001.

19. American Physical Society, “Report of the APS Study Group on Boost-Phase Intercept Systems for National Missile Defense,” Washington, DC, July 2003.

20. See Du Xiangwan, Science and Technology Foundation for Nuclear Arms Control (Beijing: National Defense Industry, 1996).