The Legality of a U.S. Space Force

[Adam Irish is an Assistant Professor of Political Science at California State University, Chico.]

President Donald Trump’s pronouncements that the United States needs to develop a “Space Force” were initially met with derision by national security establishment. In a letter to lawmakers, Secretary of Defense, James Mattis, wrote that he did not “wish to add a separate service that would likely present a narrower and even parochial approach to space operations.”

However, three Space Policy Directives, one speech by the Vice President, and one report by the Department of Defense (DoD) later, a US Space Force seems poised to move from campaign rhetoric to bureaucratic reality. Even General Mattis has changed his position.

As policy makers contemplate a US Space Force, they should keep in mind US commitment to the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies (The Outer Space Treaty). A US Space Force could, and likely would, run afoul of international space law. In addition to motivating reciprocal action by other states, a US Space Force would almost certainly endanger the peaceful use of space status quo enshrined in The Outer Space Treaty.

Goals, Justification, Structure, and Uses of a US Space Force

The Trump administration’s 2018 National Space Strategy (NSS) reframes the space in “America First” terms. It diverges from both the 2010 NSS and the 2011 DoD Report, both of which frame space in terms of international cooperation and commercial importance. After calling for peace through strength, the 2018 NSS asserts that “our competitors and adversaries have turned space into a warfighting domain” and identifies four pillars for future space policy:

• Transform to more resilient space architectures,
• Strengthen deterrence and warfighting options,
• Improve foundational capabilities, structure, and processes, and
• Foster conducive domestic and international environments for development.

Despite some early resistance by the Air Force and DoD, the 2018 DoD report falls in line with the 2018 NSS, even advancing two objectives of its own:

• “Protecting U.S. vital interests in space – ensure unfettered access to, and freedom to operate in space, in order to advance America’s security, economic prosperity, and scientific knowledge; and
• Deploy next-generation capabilities to support the warfighter” (DoD 2018, 5).

The 2018 DoD report drops the “congested, contested, and competitive” justification for US space leadership in favor of a focus on the power of rival states to affect US capabilities during times of conflict. Singling out China and Russia, the DoD pays special attention Russian directed-energy weapons the 2007 Chinese Anti-Satellite (ASAT) test, the later of which created more than 3,000 pieces of space debris. Beyond deterring attacks on US commercial satellites, the 2018 DoD report expresses concern over the “counterspace functionality” of such weapons. Specifically, that during a conflict, ASAT weapons could be used to reduce US military effectiveness by interrupting satellite communications.

The proposed structure for a US Space Force includes a Space Operations Force operating under the Space Command of a four-star general or flag officer, along with an economically and technologically focused Space Development Agency, as well as Service and Support department. This Space Operations Force poses legal complications under current international space law because it will be tasked with providing “human capital needed to develop, field, and integrate space capabilities into multi-domain warfighting” (DoD 2018, 10). In short, training and fielding a military in space.

The warfighting emphasis in the 2018 DoD report does not appear to be solely the result of DoD jargon. President Trump’s own explanation of the ends of a Space Force strikes an imperial note. At recent campaign rally, President Trump is quoted as saying, “It is not enough to merely have an American presence in space. We must have American dominance in space.” Several weeks later, when speaking at the Pentagon, Vice President Pence backed the President’s view, asserting, “…our adversaries have transformed space into a warfighting domain already. And the US will not shrink from the challenge.”

The pivot to use of force becomes clear when you compare the 2011 and 2018 DoD reports. The former report advocates for interagency cooperation while the latter calls for military leadership of a new military branch. Perhaps most striking is the 2018 DoD report’s repeated references (some two dozen) to the “battlefield” of space or “warfighting” in space. Meanwhile, neither word appears in the 2011 DoD report. As outlined, the US Space force seems destined to be used to project US power rather than explore space.

US Space Force Legality Under the Outer Space Treaty

As noted in prior writing on space law (Lee (2003); Bourbonniere and Lee (2007)), Article IV of the Outer Space Treaty specifies that “nuclear weapons or any other kinds of weapons of mass destruction” shall not be placed in orbit, installed in space, or constructed on celestial bodies. Thus, as written, the treaty does not prohibit conventional weaponry (e.g. missiles) from being placed aboard satellites (or in outer space) or states using those weapons in self-defense. However, any non-defensive use of such weaponry is also likely to violate international laws of armed conflict. And any debris generated would likely to trigger liability under both Articles VI and VII of the Outer Space Treaty as well as the 1972 Space Liability Convention should it cause or otherwise create the risk of damage to the property of other states.

The Trump administration’s Space Force proposal is a riskier proposal though. Paragraph two of Article IV of the Outer Space Treaty, reads:

“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 or other celestial bodies shall also not be prohibited.” (Art. 4, Para. 2).

Subject to an ongoing interpretative dispute between the US and other states, “peaceful purposes” does not rule out military craft or personnel acting peacefully in outer space; scientific research by military personnel is even singled out for protection. Rather, the wording of Article IV makes specific reference to “the Moon and celestial bodies” and effectively demilitarizes those bodies from the building of bases and fortifications, testing of weapons, or conducting of military maneuvers. Thus, any of the future military infrastructure built on these bodes would be in violation of existing law. As written the treaty only leaves open the question of a space-based military. A US Space Force confined by these prohibitions would be limited to operation in the space between celestial bodies, presumably in orbit aboard space stations or on ships located at Lagrange points in space, i.e. locations with unobstructed exposure to the sun for a near constant supply of solar power.

Even operating within the limited environment of outer space, a US Space Force tasked with securing US interests and space access, risks violating the broader restrictions of the Outer Space Treaty. Specifically, Article I that states “space exploration and use of outer space, including the Moon and other celestial bodies, shall be carried out for the benefit and in the interests of all countries,” and Article II’s restriction that outer space and celestial bodies are “not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.”

As with legal limitations faced by the US Navy on the high seas, a US Space Force that dominates space by imposing regulatory authority on transit or, through US occupation of space, limits the access of other states to outer space would doubtless provoke legal challenges. Yet, as the comments above indicate, that appears to be exactly the intended purpose of a US Space Force – to dominate and control space for the benefit of US national security and commerce. How this dominance is realized will matter for the US Space Force. The use of force laws extends to self-defense or UN sanctioned actions. Thus, any threatening, preemptive, or forceful behavior without provocation would still violate international law. Lastly, even if nary a shot is fired, under Article VII and IX of the Outer Space Treaty, collisions, pollution, and space debris from a US Space Force stationed in orbit or at a Lagrange point would all expose the US to legal liability should any of these items affect the well-being of other states.

In sum, there exists a small legal window in existing international space law to realize a US Space Force. Much of the dominance and warfighting language being thrown around now would undoubtedly lead the US into legally treacherous waters. Beyond a basic capacity for self-defense, the view through that small legal window is less Star Wars and more Star Trek.