Scope and Scale of Missile Defense Plans in the 2018 National Defense Authorization Act (NDAA) — February 25, 2018


Jaganath Sankaran

The 2018 NDAA outlines an ambitious range of programs on missile defenses.[1] It also provides a staggering funding increase to the Missile Defense Agency (MDA), indicating a willingness by both the Congress and the Trump administration to support both existing missile defense programs as well as new ones.

In addition to a $1.5 billion increase for “various missile procurement and development,” the 2018 NDAA also authorizes $12.3 billion for the MDA “to bolster homeland, regional and space missile defenses.”[2] The large amount increases seem to be motivated by a late White House request for “an additional $4.0 billion to support urgent missile defeat and defense enhancements to counter the threat from North Korea…”[3] In fact, the authorization substantially exceeded the initial MDA request of $7.9 billion for FY 2018, which in itself was a $379 million increase from the previous year.[4]

On the matter of the defense of continental United States, the document places substantial stock on the Ground-Based Interceptors (GBI) deployed in Alaska and California. Many proposed upgrades to the system are advised under the proviso “if consistent with the direction or recommendation of the Ballistic Missile Defense Review that commenced in 2017.” For instance, the 2018 NDAA has asked the Secretary of Defense to “designate the preferred location of a potential additional continental United States interceptor site” to host GBI interceptors if so suggested by the BMDR.[5] It also asks to “increase the number of ground-based interceptors of the United States by up to 28” subject to the 2018 defense appropriations and if consistent with the BMDR.[6] These 28 additional interceptors would add to the 44 planned to date.[7] Furthermore, the 2018 NDAA asks for a plan “to further increase such numbers” of interceptors to a total of 104 to be potentially deployed in “existing or new [sites] on the East Coast or in the Midwest.”[8] The document is silent on the strategic justification for such numbers and the potential risks to strategic stability. The decision to include such a request might also be a reflection of the internal bargaining that ensued in obtaining consensus on the 2018 NDAA. The BMDR might provide more clues as to the evolution of the future numbers of GBI interceptors to be deployed with the continental United States.

However, there are also some tangential limitations imposed to ensure sufficient rigor in testing and development. The 2018 NDAA states that the MDA “should continue to flight test the ground-based midcourse defense element at least once each fiscal year” and should “establish a more prudent balance between risk mitigation and the more rapid testing pace needed to quickly develop and deliver new capabilities to the Armed Forces.”[9] The document, however, does not define what would constitute prudent balance and under what conditions the system would be considered effective.

Also, on homeland defense, the 2018 NDAA asks the Director of the MDA to demonstrate the capability of SM-3 Block IIA interceptors to “defeat a complex intercontinental ballistic missile threat” no later than December 31, 2020.[10] Any such demonstration might open up substantial opposition from the Russia and China, further stonewalling any attempts to reduce nuclear arsenals through cooperative arms control. Also, if such a capability of SM-3 IIA interceptors is accepted as demonstrated, it is not evident how clear separation of SM-3 IA/IB and SM-3 IIA deployment methods can be achieved.

Without convincingly demonstrating such separation, it might be very difficult convince Russia, China, and other nations that the United States is not pursuing national missile defenses against Russia or China. The 2018 NDAA document, to its credit, does seem to anticipate potential risks to arms control and strategic stability from the demonstration. It tasks the Secretary of Defense to submit, not later than 120 days after the enactment of the 2018 NDAA, a report whether such a demonstration “poses any risk to strategic stability.”[11] The tasking also asks the Secretary of Defense to develop a plan “to address and mitigate such risks.”[12] The details of such plans will have important consequences for future nuclear arms control and risk reduction.

The 2018 NDAA also asks the Director of MDA to develop “a highly reliable and cost-effective persistent space-based sensor architecture capable of supporting the ballistic missile defense system” if the BMDR recommends it.[13] The NDAA document indicates that such a system should be able to perform among other things (1) precision tracking of threat missiles; (2) enabling of launch-on-remote and engage-on-remote capabilities; (3) discrimination of warheads; and (4) enhanced shoot doctrine. MDA began the development of the most recent such space-based sensor architecture, the Precision Tracking Space System (PTSS), in 2009.[14]

The PTSS program was canceled after spending around $231 million when it could not provide immediate and applicable benefits to the missile defense mission.[15] Also, a 2012 National Academies study claimed that PTSS does not “provide better [capabilities] and at a lower cost both initially and over the life cycle” in comparison to existing systems. The study also argued that “PTSS contributes little if anything to midcourse discrimination.”[16] The new program suggested in the 2018 NDAA would have to demonstrate how changes in technologies, threat estimation, operating parameters or other considerations can justify another similar venture.

Depending on the outcome of the BMDR, the 2018 NDAA also recommends that “the Secretary of Defense should rapidly develop and demonstrate a boost phase intercept capability for missile defense as soon as practicable.”[17] The document advises that “existing technologies should be adapted” in developing a boost phase system with the goal to “address emerging threats…in the Asia-Pacific region.”[18] The threat is predominantly an implied reference to North Korean missiles. However, not many more details are outlined. Is the boost phase system air-borne or ship-borne? Will it be designed specifically to address North Korean threats with a planned phasing down if and when the threat is mitigated? How will the deployment of such a system affect Chinese and Russian strategic security sensibilities? The BMDR might provide clues to these, and many other questions a boost-phase missile defense might raise.

Reflecting the concerns over North Korean missiles, the 2018 NDAA also takes up the matter of the defense of Hawaii suggesting a “sequenced approach.”[19] Some recent suggestions have been made to use the SM-3 launchers at the Navy’s Pacific Missile Range Facility along with an AN/TP-2 radar, to provide defensive coverage over Hawaii.[20] However, the 2018 NDAA suggests as part of its sequenced approach protecting the “test and training facilities of the Pacific Missile Range Facility” rather re-purposing the facility.[21] Later on in the document, without providing specifics, it suggests “the feasibility of improving missile defense of Hawaii by using existing missile defense assets that could materially improve the defense of Hawaii.” Given recent events,[22] the BMDR will probably explore the defense of Hawaii in more depth including the possibility of new missile defense deployments to the state.

In essence, the 2018 NDAA is motivated more by threat perception and less by strategic stability concerns. It discusses a plethora of programs without a detailed plan to optimize various systems. It also does not enable a broader discussion of the strategic stability concerns missile defenses provoke or the deterioration of arms control possibilities. However, once the BMDR is published, it may provide more clues to the Trump administration’s preferences on the many issues pertaining to missile defenses.


[1] “H.R. 2810 – National Defense Authorization Act for Fiscal Year 2018, 115th Congress (2-017-2018),” Online at Hereafter referred to as “H.R. 2810.” Ballistic Missile Defense programs are discussed in “Subtitle E – Missile Defense Programs.

[2] “National Defense Authorization Act for Fiscal Year 2018,” United States Senate Committee on Armed Services, Conference Report Highlights. Online at

[3] The letter requesting for additional funds can be found online at

[4] Missile Defense Agency, “Fiscal Year (FY) 2018 Budget Estimates: OVERVIEW,” 15 May 2017. Online at

[5] Ibid.

[6] Ibid.

[7] Nuclear Threat Initiative, “Pentagon to Field Additional Ballistic Missile Interceptors in Alaska,” 15 March 2013. Online at

[8] H.R. 2810, Sec. 1686.

[9] H.R. 2810, Sec. 1690.

[10] H.R. 2810, Sec. 1680.

[11] Ibid.

[12] Ibid.

[13] H.R. 2810, Sec. 1683.

[14] Missile Defense Agency, “Fact Sheet: Precision Tracking Space Systems.” Online at

[15] David Willman, “How the U.S. Missile Defense Agency burned $231 million on a program that never should have left the drawing board,” Los Angeles Times, 26 December 2015. Online at

[16] National Research Council of the National Academies, Making Sense of Ballistic Missile Defense (Washington D.C.: National Academies), p. 16. Online at

[17] H.R. 2810, Sec. 1685. In addition to boost phase missile defense, there is also mention about developing a space-based missile defense layer. By virtue of immutable orbital mechanics, a space-based missile defense layer would also at least theoretically possess intercept capabilities against Russian and Chinese strategic missiles. Such a threat might force Russian and Chinese countermeasures, including in the increase in the number of deployed weapons. It should also be noted that a boost phase capability to be effective against a regional threat such as North Korea would be extremely costly and very difficult to accomplish. See: American Physical Society, Report of the APS Study Group on Boost-Phase Intercept Systems for National Missile Defense: Executive Summary and Findings (College Park, MD: American Physical Society, July 2003). Online at

[18] H.R. 2810, Sec. 1685.

[19] H.R. 2810, Sec. 1680.

[20] Admiral Sandy Winnefeld, “Paradise Intercepted: Defending Hawaii from North Korea,” The Cipher Brief, 18 January 2018. Online at

[21] H.R. 2810, Sec. 1680..

[22] Zachary Cohen, “Missile threat alert for Hawaii a false alarm; officials blame employee who pushed ‘wrong button’,” CNN Politics, 14 January 2018. Online at

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