The Force Awakens: The Legality of the U.S. Space Force

Photo by Brian McGowan on Unsplash

Rachel Harp, Associate Member, University of Cincinnati Law Review

I. Introduction

As multiple nations continue to explore the new frontier of outer space, legal issues lurk in the evolving field of international space law.[1] Developed significantly during the Cold War by the United Nations (“UN”), space law covers mining, space traffic, damages from space debris, the militarization of space, and more.[2] Article IV of the Outer Space Treaty states that the Moon and “other celestial bodies” must be used only for peaceful purposes.[3] The treaty also prohibits placement or use of nuclear weapons and weapons of mass destruction in the Earth’s orbit, on a station, or on a celestial body.[4] While military personnel can be used for scientific space exploration, the creation of the U.S. Space Force likely violates international space law.[5]

II. Background

The UN’s Outer Space Treaty created during the Cold War provides the basis for space law and space activities.[6] It incorporates international space law principles, namely emphasizing that operations in space should be “exclusively peaceful.”[7] The U.S. Space Force as written is a defensive, specialized section of the U.S. Air Force.[8] 

A. The Outer Space Treaty

The 1966 Outer Space Treaty is “the foundation of international space law.”[9] The treaty outlines nine principles as follows: (1) the exploration and use of outer space should be carried out for the benefit of all humankind; (2) outer space shall be free for exploration and use by all signatories; (3) outer space is not subject to claims of sovereignty or occupation; (4) signatories cannot place nuclear weapons or weapons of mass destruction in space; (5) the Moon and other celestial bodies must be used for exclusively peaceful purposes; (6) astronauts shall be regarded as “the envoys of [hu]mankind;” (7) signatories are responsible for national space activities; (8) signatories are liable for damage caused by their space objects; and (9) signatories must avoid contamination of space and celestial bodies.[10]

Article IV of the Outer Space Treaty is the main article discussing space militarization.[11] It prohibits nuclear weapons and weapons of mass destruction in space and mandates that “[t]he Moon and other celestial bodies shall be used…exclusively for peaceful purposes.”[12] Further, signatories cannot establish military bases or installations on celestial bodies, nor can States test weapons in space.[13] States are, however, permitted to use military personnel for scientific research or other “peaceful purposes.”[14] Article II specifies that States cannot assert sovereignty in space.[15] There is a notable lack of definitions in the Outer Space Treaty, leaving signatories to apply their own definitions to “peaceful purposes.”[16] Generally, UN States are prohibited from threat or use of force except in self-defense.[17]

B. Space Force

The Space Force was signed into law by Former President Trump in December of 2019.[18] Though the idea of a Space Force was satirized when first mentioned, Trump saw to its creation.[19] Trump emphasized “American superiority in space” and stated that “[s]pace is the world’s newest war-fighting domain.”[20] The legislative history reflects similar notions, as Chairman of the Senate Committee on Armed Forces stated that the intention if Space Force is to “restore our margin of dominance in space.”[21]

The Space Force will (unfortunately) not be battling asteroids, aliens, or space wizards (“the big three” threats to Earth according to science fiction movies and television), but it is instead intended to operate defensively to protect U.S. space interests.[22] The functions of the Space Force include providing “(1) freedom of operation for the United States in, from, and to space; and (2) prompt and sustained space operations.”[23] Space Force is charged with the duties of protecting US space interests; deterring aggression in, from, and to space; and conducting space operations.[24]

III. Discussion

As tempting as it might be to see “Star Wars” in real life, the U.S. Space Force likely violates international law. The Space Force’s duties and functions are written in non-aggressive terms, but its history and purpose suggest that the U.S. may not actually “come in peace.”[25] The Space Force has limited operating capacity, as it cannot assert U.S. dominance, issue threats, or test weapons in space.[26] Former President Trump explicitly wished to assert U.S. dominance in space and stated that space will be the new war territory.[27] The legislative history of Space Force further emphasizes U.S. dominance and aggression in space.[28] These assertions violate major Outer Space Treaty principles, including the prohibition of establishing sovereignty in space and using space only for peaceful purposes.[29] The creation of the U.S. Space Force can also be seen as a “threat of force” based on its history of aggressive and dominant remarks.[30] While President Biden has yet to iterate a stance on Space Force, abolishing the military branch would require an act of Congress and is unlikely to happen anytime soon.[31]

The U.S. Space Force further threatens international relations by indirectly encouraging other nations to create similar space military branches and encouraging a new “race to space.”[32] Concerns about the weaponization of space existed before a U.S. “space command” was contemplated.[33] The Outer Space Treaty prohibits placement of nuclear weapons and weapons of mass destruction in space and prohibits weapons testing, but it does not speak to merely placing other weapons in space.[34] The U.S. and other world powers have various weapons in space, and much space technology serves a “dual purpose” as a research vehicle with the potential to be weaponized.[35] The U.S. Space Force will likely contribute to even more weapons in space and may even violate other UN space treaties regarding traffic, debris, and pollution.[36]

IV. Conclusion

The militarization and weaponization of space will continue to proliferate, as the U.S. has instigated a new type of arms race. “Peaceful purposes” in the Outer Space Treaty has been generally defined to merely mean “non-aggressive,” though the U.S. Space Force could be seen as a “threat of force.”[37] While the Space Force legislation is “non-aggressive,” asserting U.S. dominance in space directly violates Article II of the Outer Space Treaty and arguably violates Article IV.[38] Space battles should remain science fiction, and UN countries should uphold the Outer Space Treaty principles of using space for humankind’s benefit and peace.[39]


[1] See generally Louis de Gouyon Matignon, The Future Space Legal Issues, Space Legal Issues (Sept. 24, 2019), https://www.spacelegalissues.com/the-future-space-legal-issues/; Deanna Paul, Space: The final legal frontier, Wash. Post (Aug. 31, 2019), https://www.washingtonpost.com/technology/2019/08/31/space-final-legal-frontier/.

[2] de Gouyon Matignon, supra note 1; Space Law Treaties and Principles, United Nations, https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties.html (last visited April 14, 2021).

[3] G.A. Res. 2222 (XXI), at 14, Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (Dec. 19, 1966) [hereinafter Outer Space Treaty]. See also celestial body, Merriam-Webster, https://www.merriam-webster.com/dictionary/celestial%20body (last visited April 14, 2021) (defining “celestial body” as “an aggregation of matter in the universe that constitutes a unit (as a planet, nebula) for astronomical study”).

[4] Outer Space Treaty, at 14.

[5] Id. See 10 U.S.C. §§ 9081-9083 (“The Space Force”).

[6] Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, United Nations, https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introouterspacetreaty.html (last visited April 14, 2021). 

[7] Id.; Outer Space Treaty at 14.

[8] 10 U.S.C. § 9081.

[9] Paul, supra note 1.

[10] Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, United Nations, https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introouterspacetreaty.html (last visited April 14, 2021).  See also Outer Space Treaty, at 13-15.

[11] Outer Space Treaty at 14.

[12] Id.

[13] Id.

[14] Id.

[15] Outer Space Treaty, at 13.

[16] Lauren Hauck, Comment: The Rogue One: Trump’s Space Force and the Threat of a New Cold War, 42 Haw. L. Rev. 113, 133 (2020); Outer Space Treaty, at 13-14.

[17] U.N. Charter art. 2 and 51. See also Hauck, supra note 15, at 144.

[18] Merrit Kennedy, Trump Created The Space Force. Here’s What It Will Actually Do, Nat. Pub. Radio (NPR) (Dec. 21, 2019), https://www.npr.org/2019/12/21/790492010/trump-created-the-space-force-heres-what-it-will-do.

[19] Id.

[20] Id.

[21] Hearing to Receive Testimony on the Proposal to Establish a United States Space Force Before the S. Comm. on Armed Serv., 116th Cong. (2019). See also Hauck, supra note 15, at 145-46.

[22] Id.; The Falcon and The Winter Soldier: The Star-Spangled Man, Disney+ (2021); 10 U.S.C. § 9081.

[23] 10 U.S.C. § 9081(c).

[24] 10 U.S.C. § 9081(d).

[25] 10 U.S.C. § 9081; Kennedy, supra note 17; Hauck, supra note 15, at 143-47.

[26] Outer Space Treaty, 13-15; Adam Irish, The Legality of a U.S. Space Force, OpinioJuris (Sept. 13, 2018), http://opiniojuris.org/2018/09/13/the-legality-of-a-u-s-space-force/.

[27] Kennedy, supra note 17.

[28] See sources cited supra note 21.

[29] See sources cited supra note 10.

[30] U.N. Charter art. 2 and 51; Irish, supra note 24.

[31] Robert Burns, Biden seen likely to keep Space Force, a Trump favorite, Associated Press (AP) (Jan. 28, 2021), https://apnews.com/article/joe-biden-space-force-edcb01683ab38e740ae87530c49ecd4e.

[32] Hauck, supra note 15, at 157-59 (stating that the creation of the U.S. Space Force violates international law and will lead to a new Cold War); Alexis and Jessica Ramsey, Article: Space Force and the Outer Space Treaty: One Small Step Forward for a Man, One Giant Leap Backward for Humankind, 54 U.S.F. L. Rev. 4, 20 (2020).

[33] Hauck, supra note 15, at 136; Paul, supra note 1.

[34] Outer Space Treaty, at 14. See sources cited supra note 31.

[35] Paul, supra note 1.

[36] Irish, supra note 24. See sourcescited supra note 2.

[37] Paul, supra note 1; Hauck, supra note 15, at 133; Kennedy, supra note 17.

[38] 10 U.S.C. § 9081; Outer Space Treaty, at 13-14.

[39] Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, United Nations, https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introouterspacetreaty.html (last visited April 14, 2021). 

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