This is false. The Outer Space Treaty places no limits on anti-satellite weapons and never has. During the Cold War neither superpower actively sought an international treaty that would restrict their development of anti-satellite weapons. There were several reasons for this, but a primary one was the difficulty in verifying such a treaty, especially considering the nature of the Soviet ASAT system, which utilized rockets that were indistinguishable from active ICBMs unless they were physically inspected.

Despite the lack of ASAT arms control, the United States has not demonstrated much enthusiasm or interest in developing an ASAT weapon since the beginning of the space age. This was because ASAT weapons were expensive, limited in military utility, and provocative. In fact, it appears that the decisive factor in developing or not developing an American ASAT has often been the existence of an enemy ASAT capability. Given the high cost and limited utility of the weapon, multiple justifications were needed to make it possible, and the one that tipped the balance in favor of development was the existence of an enemy that needed to be deterred.

The international situation has changed significantly since the Cold War. However, many of the conditions that make ASAT weapons not very attractive remain in effect, and some of the conditions that led to their approval in the past do not exist today.

Banning WMDs, not ASATs

The Outer Space Treaty resulted from a long series of discussions within the United States government and eventually between the two superpowers. The most important section of the Outer Space Treaty is Article IV, which states:

“States Parties to the Treaty undertake not to place in orbit around the Earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner.

The Moon and other celestial bodies shall be used by all States Parties to the Treaty exclusively for peaceful purposes. The establishment of military bases, installations and fortifications, the testing of any type of weapons and the conduct of military maneuvers on celestial bodies shall be forbidden. The use of military personnel for scientific research or for any other peaceful purposes shall not be prohibited. The use of any equipment or facility necessary for peaceful exploration of the Moon and other celestial bodies shall also not be prohibited.”

Like most Cold War era treaties, this one essentially codified actions that the superpowers did not find attractive to pursue in the first place. Putting weapons of mass destruction such as nuclear bombs in orbit makes little sense. Orbital mechanics means that an orbiting weapon spends most of its time out of range of its target, unlike an ICBM that is always the same distance from its target. In addition, limited computing power also restricted the utility of an orbiting bomb, because it could not be programmed with a large target list. Finally, command and control of a weapon overhead was worrisome—what if the other side was able to jam or take over the weapon? Neither side therefore wanted to place weapons of mass destruction (WMDs) in orbit, making a treaty banning them possible.

Similarly, there is no logical reason to base weapons on other planets unless they are defending other installations there. If both superpowers had active moonbases they might take weapons to defend them. But neither had plans for moonbases and so it was an easy step to ban all weapons—not simply WMDs—from the moon, Mars, and other terrestrial bodies.

A State Department website explains the origins and significance of the Outer Space Treaty, noting that its two most important provisions are the ban on WMDs and the ban on weapons on other terrestrial bodies. Nowhere does it mention a ban on ASATs. The Outer Space Treaty mentions nothing about ASATs, and for good reason—both the United States and the Soviet Union already possessed them when they signed the treaty.

The United States had Program 437, a system that utilized a Thor ballistic missile equipped with a 1.4 megaton nuclear warhead. It would launch from Johnston Island in the Pacific Ocean and fly essentially a ballistic trajectory. Its primary target was intended to be Soviet Fractional Orbital Bombardment Systems (FOBS) weapons, which were nuclear weapons placed in orbit that were brought down before completing a single orbit of the earth. (It is worth noting that FOBS would have technically violated the Treaty if it was actually used. But that would only happen during World War 3, during which international niceties would be suspended for the duration of hostilities.) Program 437 operated from 1964 until the early 1970s, at which time the inefficiency, expense, and limited usefulness of the weapon led to its withdrawal from service. Notably the Program 437 ASATs were both ground-based and used a nuclear weapon (a weapon of mass destruction), but did not enter orbit. These facts did not prevent the United States from signing the Outer Space Treaty, nor did any other signatories charge that the Americans were in violation of a treaty that they were signing.

The Soviets possessed their own ASAT weapon. Known as the “satellite destroyer” (or “Istrebitel Sputnikov” in Russian), it was fitted atop a modified ballistic missile and used the co-orbital technique, meaning that it entered the same orbit as its target and essentially got close enough to it to fire a weapon, sort of like a Claymore directional mine or a shotgun blast. Work on the IS started in the early 1960s and it was tested through the early-1970s. The existence of the satellite destroyer also did not prevent the signing of the Outer Space Treaty.

The existence of both of these weapons did vastly complicate any effort to ban ASAT weapons, however. In order to verify such a ban, each side would have to inspect the payloads of the other side. During the early 1960s the United States held substantial internal discussions about this subject, particularly the concern that the Soviets would want to inspect American rockets carrying reconnaissance satellites. This was discussed in the NSAM 156 Committee, named after the National Security Action Memorandum that established it.

Over time, those concerned with ASAT arms control both inside the executive branch and in Congress determined that on-site verification was impossible, and so any ban would have to focus on testing which should be detectable under many circumstances. But the fact that the Soviet weapon had already been tested and was considered to be operational tended to complicate and nullify this debate.

Arming for the high frontier

The history of American ASATs demonstrates one of the lesser known secrets of anti-satellite weapons. It has not been simply arms control that killed previous American ASAT weapons, it was both their high cost and their limited utility. The Program 437 ASAT weapon was not very useful. There were only limited orbits that it could reach. It required significant prep time because the missiles were not kept on permanent alert like an ICBM. (In fact, the missiles were kept in California and had to be flown to Johnston Island to be used.) The number and types of targets that it could engage were also limited. In 1972 a hurricane damaged the launch facilities and the Pentagon decided that it would cost too much to continue the system. Program 437 became non-operational and was then cancelled a couple of years later.

Rather surprisingly, the United States did not immediately begin development of a new, more useful ASAT system even though Soviet satellites still posed a threat. If ASATs were such inherently useful devices, one would have expected the United States to start building a new one. However, it was not until early 1977 that the United States initiated a new ASAT program, and it did so primarily because the Soviet Union had resumed testing its satellite destroyer. A secret document signed by President Ford, declassified only last year, indicates that there were two primary reasons to begin development of a new ASAT weapon: to attack Soviet military satellites and to deter the Soviets from attacking American satellites.

This resulted in the American development of an ASAT designed to be launched from an F-15 aircraft. The advantage of this approach was that the weapon could intercept a larger number of Soviet satellites in different orbits compared to a ground-launched weapon. At the time the United States also began another program, an “electronic ASAT” effort to try and take over or jam Soviet satellites. The very existence of this program was classified, but it does not appear to have progressed.

The development of the F-15 ASAT weapon proceeded relatively slowly until 1981, when the Reagan administration placed renewed emphasis on it. But the difficulty of the task became apparent during an early review, and the planned operational date for the weapon slipped from 1985 to 1987—ten years after its initial approval. The first test launch occurred in 1984. A full-up test took place in 1985. By this time, however, Congress intervened, concerned that the American ASAT would prompt the Soviet Union into improving their own ASAT capability.

In October 1986 President Reagan signed National Security Study Directive No. 4-86, which was classified “Secret.” The directive noted recent action by Congress to continue restrictions on ASAT testing. Reagan stated that although the weapon was “a good first step towards deterring the Soviet Union from using its ASAT capability, support for our program has eroded due to its relatively high cost and limited capability.” However, Reagan continued, “fortunately, we have the technology to do much better with newer systems, given more time to develop other approaches. Either way, the US ASAT program must be continued.” This directive was also declassified only last year.

While it is common for writers to claim that it was congressional concern about arms control that killed the F-15 ASAT, Reagan’s directive indicates that both the cost and the limited capabilities of the system were major concerns. If anything this was an understatement. Whereas the original cost estimate for the program had been $500 million. By 1985 it had risen to a whopping $5.3 billion, which included the cost of 48 F-15 aircraft and 112 interceptor missiles. In addition, the Air Force leadership had never been very enthusiastic about the weapon and Air Force generals certainly felt that they had better uses for two squadrons of F-15s. By the late 1980s the F-15 ASAT was dead and a new effort was resurrected in its place.

That project, known as the Kinetic Energy ASAT, or KE-ASAT, was funded at $91 million in 1991, but quickly cut back after the end of the Cold War. The project has experienced a rather bizarre existence, kept alive through pork-barrel politics essentially on paper only. Theoretically it still exists at some level, but nobody considers it a real program.

Airborne Laser, a program originally designed for use in missile defense applications, could be turned into an ASAT weapon. (credit: US Air Force)

The current and future ASAT?

If the past is prologue, then the long American experience with ASATs has demonstrated that developing truly useful systems is difficult and expensive, and senior American military officials have rarely shown much conviction in pursuit of a capable ASAT. Those conditions are likely to continue. And one of the primary past justifications of developing an ASAT, to deter an adversary that also had substantial space assets at risk, no longer exists.

There are many problems with developing an American ASAT capability, and arms control is probably the least of them. One of the problems is a lack of attractive targets, even theoretical ones. The proliferation of foreign remote sensing satellites would appear to complicate problems for American military operations, because now more countries can monitor what the United States is doing. This, though, does not inherently translate into more targets for the US to shoot at, at least not obvious ones. Many of these satellites are friendly, or at least neutral. Just as the United States does not build F-22 Raptors to counter the annoying French government’s air force, it does not require ASATs to target France’s Helios spy satellite. Nor does the United States need to target remote sensing satellites developed by Israel, India, Brazil, or any of the many other countries that have begun acquiring low-resolution systems.

Another problem is the range of scenarios in which an ASAT would be militarily useful. One of the oft-cited examples was the case during the 1991 Persian Gulf War where the United States Army made a surprise “left-hook” maneuver in the Iraqi desert. ASAT proponents claimed that if the Iraqis had a reconnaissance satellite, this maneuver would have been impossible. That is not necessarily true. The United States could have moved faster than the Iraqi ability to respond, and the coalition forces used substantial deception efforts, such as the threat of an amphibious attack from the Gulf, to keep the Iraqis guessing. Similarly, in order to conceal the mobilization for the left-hook, the United States would have had to destroy an Iraqi satellite long before it planned on invading. All of these conditions highlight that an ASAT weapon is unlikely to represent a silver bullet that is vital to success.

There are currently a few countries, notably China and Iran, which could become future adversaries that have or are acquiring space capability. It has now been reported that China may have a reconnaissance satellite masquerading as a weather satellite. Iran is developing a launch vehicle and Israeli media sources have claimed that the Iranians are developing a reconnaissance satellite to put on it. But the cost of denying China and Iran their space assets may be more than it is worth. During the Cold War the United States Navy preferred to avoid Soviet ocean surveillance satellites rather than destroy them. Navy admirals believed—perhaps naively—that they could do this successfully. The limited theoretical capabilities of potential future adversaries will not match the actual capabilities the United States faced during the Cold War, meaning that there is less justification for them now than there was nearly three decades ago.

There are also numerous downsides to traditional kinetic ASAT weapons. They generate debris, for starters, making orbits that the United States needs to use unhealthy for our own satellites. The United States might also find itself in a situation where it is more desirable to temporarily shut down an adversary’s satellite than to permanently do so. For these and other reasons the United States increasingly favors “softer” methods of denying an enemy’s space assets than blowing their satellites out of the sky. Jamming or incapacitating them is the ideal option. If the United States can destroy a ground station with an existing cruise missile, that would prove far more cost effective than spending billions to develop an ASAT capability. Why develop a new weapon when existing ones can already do the job?

This is not to say that an ASAT weapon does not have any utility for the United States. It does. It is arguably better to have a blunt arrow in the quiver than no arrow at all. However, if the arrow is blunt, then there is no reason to pay full price for it.

There are some existing options. The Air Force recently deployed the Counter Communications System (CCS). Although details are limited, this appears to consist of three ground-based, portable jamming packages built from commercial off-the-shelf hardware. It is a reversible (i.e. non-destructive) method of denying an adversary communications capability, meaning that it can be used in a wider range of circumstances. The CCS satellite jammer is a natural outgrowth of recent American experience. During the first Persian Gulf War the United States determined that some Iraqi weapons systems, particularly the ground radars for some surface-to-air missiles and the powerful radar on the MiG-25 interceptor aircraft, could jam American satellites. It is an open secret in the commercial comsat world that a ground station can be used to jam another comsat—something that happens by accident on a semi-regular basis.

The US Air Force also recently began studying the possibility of utilizing the YAL-1A Airborne Laser for missions other than missile defense. The Airborne Laser (or ABL) is mounted in a modified 747-400F aircraft and uses a powerful laser to intercept ballistic missiles hundreds of miles away. It could theoretically be pointed up instead of sideways, and destroy a satellite, probably simply by overheating it so that its electronics fail. There are several operational advantages of this. One is that it does not create debris in orbit, just a dead satellite—although unlike the CCS, this is not reversible. Another advantage is that the weapon is paid for and operating for another mission,so any ASAT capability would be a bonus. However, ABL has run into numerous development problems of its own and has risked cancellation in recent years. If its missile defense mission is canceled, its ASAT mission would probably not justify the cost of operating the aircraft.

The advantage of both of these approaches to ASAT is that they are relatively inexpensive, either by utilizing commercial equipment or piggybacking on another mission. An additional advantage is that they are low visibility, not creating the kind of provocative threat that leads to international complaints, foreign or domestic calls for arms control, or a potential ASAT arms race.

But the United States does not need to pursue a more active, provocative, or expensive ASAT development than what it already has. The threat does not justify it, and rarely has.

Dwayne A. Day is the associate editor of Raumfahrt Concret, a German aerospace magazine, and frequently writes on military and civilian space programs for several publications. His history of the F-15 ASAT program appeared in the December 2004 issue of Spaceflight magazine.