In Defence of the PPWT Treaty: Toward a Space Weapons Ban

Cesar Jaramillo Space Security

Cesar Jaramillo

The Ploughshares Monitor Winter 2009 Volume 30 Issue 4

The draft Treaty on Prevention of the Placement of Weapons in Outer Space and of the Threat or Use of Force against Outer Space Objects (PPWT) (CD 2008), jointly introduced to the Conference on Disarmament (CD) by Russia and China in 2008, constituted a welcome step toward the non-weaponization of space. It was—and continues to be—the most promising proposal to fill the normative void in the current space security treaty regime. However, almost two years after its introduction, the international community has failed to embrace this unique opportunity to lay down the foundation for a robust, unambiguous, and universal space security treaty that unequivocally prohibits the weaponization of space.


The existing legal regime that tackles the potential weaponization of outer space is outdated, inadequate, and insufficient. Moreover, the rapidity with which space-related technologies are being developed seems to be widening the gap between military applications that may affect space assets and the precarious normative architecture that should regulate them. The fact that space will inevitably become more complex and congested each year underscores the need for a comprehensive space security treaty that builds on what little international law exists in this realm and not only reflects current threats to space security, but also tackles the emerging legal questions that inevitably arise as space becomes a more convoluted domain.

The PPWT—while not perfect and subject to revisions—represents what is undoubtedly the most substantive effort thus far to embed the oft-expressed desire to maintain a weapons-free outer space in international treaty law. It is true that the 1967 Outer Space Treaty specifically bans signatory states from placing nuclear weapons and other weapons of mass destruction in orbit and calls for the peaceful exploration of outer space. However, it does not explicitly refer to the placement or use of other types of weapons in outer space or the use of earth-based weapons against space targets—activities which clearly need regulation, if not outright prohibition.

It is often said that the perils inherent to the indiscriminate weaponization of space are perhaps only comparable to those posed by nuclear weapons, although much of this assessment rests on speculation, since outer space has not yet seen a scenario of direct military confrontation. Indeed, it is assumed that there have been no weapons placed in space to date as there have been neither claims nor denunciations of such behaviour by any state, and considerable efforts are being made in diverse governmental and nongovernmental circles to ensure that this delicate threshold is preserved. To be sure, a distinction must be made between militarization and weaponization: while the former has arguably already happened, given the widespread use of satellites for military applications such as reconnaissance and intelligence, it is the latter that is the primary focus of proponents of a space security treaty.

Not surprisingly, a resolution on the Prevention of an Arms Race in Outer Space (PAROS) has been introduced at both the CD and the First Committee of the UN General Assembly and has garnered near-unanimous support year after year—with the notable exception of the United States and Israel.1 In this context, the PPWT draft treaty introduced at the CD in February 2008 has been touted as a practical way to “nip the problem of PAROS in the bud” (UNIDIR 2008, p. 147). If there is a ban on space weapons, the rationale goes, there will be no arms race to prevent.

The PPWT draft treaty

What, then, makes the PPWT proposal worthy of serious consideration by the international community? In other words, why is it an appealing alternative to the status quo? The PPWT is the first draft treaty on outer space ever presented at the UN Conference on Disarmament, which is the quintessential international forum for addressing multilateral disarmament agreements. In fact, the PPWT builds upon elements contained in a 2002 Working Paper presented at the CD by a group of countries that also included Russia and China. Technically speaking, though, the PPWT Treaty focuses not on disarmament but prevention, as outer space is currently considered to be weapons-free and, thus, there is nothing to disarm. Still, the CD seems to be the obvious repository for such a proposal and most member states have welcomed its introduction.

Specifically, as implied in the name of the treaty, the PPWT seeks to ban two different yet interrelated conducts:

  1. the placement of weapons in outer space and
  2. the threat or use of force against outer space objects.

The first initiative sensibly eliminates the fundamental prerequisite for the actual utilization of space weapons: their placement in space. The PPWT treaty defines weapon in outer space in a thorough and comprehensive manner as:

Any device placed in outer space, based on any physical principle, which has been specially produced or converted to destroy, damage, or disrupt the normal functioning of objects in outer space, on the Earth or in the Earth’s atmosphere, or to eliminate a population or components of the biosphere which are important to human existence or to inflict damage on them. (Article 1C)

Clearly, if the Treaty enters into force, such a broad definition would contribute decisively to the goals of PAROS and preventing space from becoming an arena of military confrontation. Notably, it encompasses weapons placed in space that can be used not only against other space objects, but also against Earth-based objects. Thus, it seems apparent that the framers of the PPWT strove to minimize the room for ambiguity and interpretation with regard to the conditions under which a device in space can be considered a weapon. Again, a weapon in space need not be used against an adversary for there to be a violation of the treaty, as its mere placement in space would be considered a breach of the treaty.

Similarly, the second focal point of this treaty, against the threat or use of force against outer space objects, provides a comprehensive ban on any aggressive action against objects in space, defined as:

Any hostile actions against outer space objects including, inter alia, actions aimed at destroying them, damaging them, temporarily or permanently disrupting their normal functioning or deliberately changing their orbit parameters or the threat of such actions. (Article 1E)

A positive characteristic of this definition is that there is no indication that hostile actions must originate in space. That is, according to the treaty, outer space objects should be free from hostile interference regardless of where it originates. The implication is that Earth-based weapons systems capable of striking targets in space are included.

Challenges to the implementation of the PPWT

Perhaps the biggest obstacle to the adoption of the PPWT has been the staunch US opposition—to the draft treaty in particular and to any legal measure designed to restrict its options in space. In 2007, the US Permanent Representative to the CD, Christina Rocca, said, “We continue to believe that there is no arms race in space, and therefore no problem for arms control to solve” (US Mission to the UN in Geneva, 2007). Such opposition by the Bush Administration was hardly surprising, as the US has recently rejected any binding mechanisms that could restrict its ability to operate freely in outer space. Moreover, this reluctance to abide by multilateral legal regimes related to space security has been codified in its National Space Policy (US Office of Science & Technology Policy 2006), which specifically states that:

The United States will oppose the development of new legal regimes or other restrictions that seek to prohibit or limit U.S. access to or use of space. Proposed arms control agreements or restrictions must not impair the rights of the United States to conduct research, development, testing, and operations or other activities in space for U.S. national interests.

It is highly unlikely that the PPWT draft treaty will ever see the light of day as a binding multilateral legal instrument unless the recalcitrant US position is somehow moderated. That said, the US National Space Policy is currently under review by the Obama Administration, with an expected completion date of early 2010. If the position taken by the Obama administration on issues such as nuclear disarmament is any indication, the review may warrant cautious optimism about a change in position on space security to one that embraces multilateralism.

Several observers have also pointed to areas of the treaty in which shortcomings and inconsistencies can be identified. For instance, the treaty has been criticized because it does not specifically ban the development and testing of earth-based anti-satellite weapons (ASAT). The proponents of the PPWT, Russia and China, have argued that while such a ban was omitted because such activities cannot be readily verified, the PPWT “does prohibit the use of such systems against space objects for hostile purposes” (CD 2009, p. 4).

Certainly, there is an inconsistency to be observed in this case. That is, if ASATs are not to be used, their development and testing would seem counterintuitive and contrary to the overall aims of the treaty.

Likewise, it is not entirely clear if, under the treaty, an attack by a state on its own satellite would be considered a hostile act, not to mention the implications that this would have on the creation of space debris. If so, then some might argue that the PPWT lacks a provision for instances when there may be a legitimate need to strike one’s own satellite. This could be due to satellite malfunction, risk of reentry, sensitivity of information that could potentially be extracted from the satellite, etc.

To be sure, there are other points where the PPWT lacks precision, has potential loopholes, or is subject to interpretation. These shortcomings notwithstanding, the PPWT remains the most highly structured state-originating proposal that has been introduced in the CD with the aim of preventing the weaponization of space. With the necessary revisions and consultations, it could serve as a building block in a broader space security legal regime.

An urgent matter

Time is of the essence for a weapons ban. General Xu Qiliang, chief of the Chinese People’s Liberation Army Air Force, was recently quoted as saying, “as far as the revolution in military affairs is concerned, the competition between military forces is moving towards outer space… this is a historical inevitability and a development that cannot be turned back” (Daily Telegraph 2009). Beyond the paradox of his nationality—China being one of the primary sponsors of the PPWT—and the degree to which his statement reflects the official stance of the Chinese government, his words are a grim reminder of the risks associated with the weaponization of space.

If space weapons are indeed placed in orbit, with the utilization or threat of utilization by any state, the event will likely trigger an arms race, with potentially disastrous results. It is imperative to act now in moving toward a space weapons ban, before the first hostile weapon is launched.

If the international community fails to act decisively, there will probably be a ratchet effect, whereby the process of space weaponization will not go backwards once it is set in motion. The PPWT could stand in the way of that dangerous possibility and should be afforded the attention it deserves, so that space can be preserved as a peaceful global commons.



  1. The United States has voted against PAROS during three of the past four years, and abstained on the last vote in October 2009. Israel has always abstained.


Conference on Disarmament. 2008. Draft Treaty on Prevention of the Placement of Weapons in Outer Space and of the Threat or Use of Force against Outer Space Objects. CD/1839.

———. 2009. Principal Questions and Comments on the Draft PPWT, and the Answers Thereto. August 18, CD/1872.

The Daily Telegraph. 2009. Space arms race an inevitability. November 2.

United Nations Institute for Disarmament Research. 2008. Security in Space: The Next Generation – Conference Report, 31 March – 1 April 2008.

United States Mission to the United Nations in Geneva, 2007. Statement to the Conference on Disarmament By Ambassador Christina Rocca, U.S. Permanent Representative.

United States Office of Science & Technology Policy. 2006. National Space Policy.

Spread the Word