Update on Aegis SM-3 Block IIA against ICBMs (June 5, 2018)

In a post nearly two years ago, I argued that the SM-3  Block IIA interceptor, scheduled to begin deployment on U.S. (and Japanese) ships and Aegis Ashore sites in the next few years, would almost certainly be capable of intercepting ICBMs (at least in the absence of effective countermeasures).  Moreover, they could cover the entire United States from a relatively small number of locations. I further argued that since these interceptors would likely be deployed in large numbers, and often on mobile platforms, their deployment could pose a severe threat for any possible reductions in nuclear forces by the United States and Russia.


In this post, I provide some updated additional information about the capabilities of the Block IIA against ICBMs and plans to test the interceptor against an ICBM-range target.


A 2009 Missile Defense Agency slide illustrating the SM-3 Block IIA capability against an ICBM (although this slide is widely available on the internet, I have not been able to identify the original briefing it was part of).

Testing the SM-3 Block IIA against an ICBM Target

The most important recent development is the requirement laid out in the November 2017 FY 2018 National Defense Authorization Act that “The Director of the Missile Defense Agency shall – (1) not later than December 31, 2020 conduct a test to evaluate and demonstrate, if technologically feasible, the capability to defeat a simple intercontinental ballistic missile threat using the standard missile 3 block IIA missile interceptor.”[1] The Missile Defense Agency (MDA) is currently planning for this test and could conduct it well before the end of 2020 deadline.  In May 2018, Rear Admiral Jon Hill, the Deputy Director of the MDA, said about this test: “It has been legislated, we have a plan, it is in our test plan, and we’re going to execute.” [2]

The MDA has recently severely cut back on making public information about its testing plans and schedules. Nevertheless, Admiral Hill did indicate that the Block IIA test against an ICBM would not occur until after the Ground-based Midcourse Defense system’s FTG-11 test, in which a salvo of two ICBMs were to be intercepted by two Ground-Based Interceptors (GBIs).  He stated that: “We made a conscious decision within the agency to prioritize the GMD salvo test.  We want to test the GBI against a salvo of ICBM targets.  So we did not want to pull a target away to go do that IIA test and lose that opportunity to characterize the performance of two GBIs going after an ICBM.”[3]

As of April 2016, FTG-11 was scheduled for the last quarter of calendar year 2017.[4]  However, by May 2017, it had slipped to August or September 2018.[5] Since then, the date of the test has apparently further slipped. In March 2018, MDA Director Lt. General Samuel Greaves stated that the test would take place in Fiscal Year 2019.[6]  Thus it now appears that FTG-11 will not take place until at least October 2018, and the test of the Block IIA against an ICBM sometime after that.

SM-3 Capability against ICBMs

A May 2017 report by the Government Accountability Office stated that the SM-3 Block IIA seeker was not designed to operate against ICBMs and that some defense officials were concerned that the seeker has limitations that might “impact its discrimination capability and warfighter decision timelines.”[7] However, the same report also revealed that MDA intends to use the SM-3 Block IIA seeker in its new Redesigned Kill Vehicle (RKV) that will be deployed on the GMD system’s GBI interceptors beginning in the early 2020s.[8]

MDA seems confident that the SM-3 Block IIA can intercept ICBMs.  In May 2018, Rear Admiral Jon Hill, the MDA Deputy Director, also stated that “So we’ve got GBI, and to have this additional layer of the SM-3 Block IIA will be very exciting. So we’re going to do that test to prove it out. If you do the math and do the analysis, we’ve got that capability, and so we just need to go prove it to ourselves.”

According to Raytheon (the manufacturer of the SM-3 Block IIA), the Block IIA already has the speed, range and altitude capabilities needed to intercept ICBMs.[9] All that is needed are some software changes.  According to Rondell Wilson, lead engineer for air and missile defense at Raytheon: “On the RKV program, we’re developing algorithms to improve the performance capability of that sensor. It’s nothing more than software and firmware.  That goes directly back into SM-3 Block IIA, and now you have an ICBM-killer capability.”[10]  He further stated: “We can provide SM-3 Block IIA ashore as an under-layer capability for GBI, thereby maximizing the magazine depth of those high-values GBIs.  We can do that immediately.”[11]

Other SM-3 Block IIA developments

(1) The FY 2018 2017 National Defense Authorization Act also requires the Secretary of Defense to prepare a report on the SM-3 Block IIA and strategic stability. Specifically, it states:

Not later than 120 days after the date of enactment of this Act, the Secretary of Defense shall submit to the Congressional Committees a report –

            (1) that indicates whether demonstrating an intercontinental ballistic missile defense capability against North Korean ballistic missiles by the standard missile 3 block IIA missile poses any risk to strategic stability; and

            (2) if the Secretary determines under paragraph (1) that such a demonstration poses such risks to strategic stability, a description of the plan developed and implemented by the Secretary to address and mitigate such risks, as determined appropriate by the Secretary.[12]

The due date for this report has passed, but I have seen no public mention of it. At a minimum, it does not seem to have affected MDA’s planning for the test.

(2) The estimated cost of the SM-3 Block IIA has increased significantly over the last several years.  A May 2018 report from the Government Accountability Office stated that the price of an SM-3 Block IIA interceptor had increased from $24 million in FY 2014 to $39 million in FY 2017, in part because of a decrease in the number of interceptors purchased.[13]


[1] FY 2018 National Defense Authorization Act, November 2017, section 1680.  Online at: https://www.congress.gov/115/crpt/hrpt404/CRPT-115hrpt404.pdf.

[2] Missile Defense Advocacy Alliance (MDAA),” New Layers” briefing transcript, May 16, 2018.  Online at: http://missiledefenseadvocacy.org/wp-content/uploads/2018/05/New-Layers-CRT-Transcript.pdf.

[3] MDAA, “New Layers.”

[4] “Update on Future Ground-Based Midcourse (GMD) Flight Tests,” Mostlymissiledefense blog, April 20, 2016.  Online at: https://mostlymissiledefense.com/2016/04/20/update-on-future-ground-based-midcourse-gmd-flight-tests-april-20-2016/.

[5] U.S. Department of Defense, “Department of Defense Off-Camera Press Briefing by Vice Admiral James Syring on Missile Defense,” News Transcript, May 31, 2017.  Online at: https://www.defense.gov/News/Transcripts/Transcript-View/Article/1198464/department-of-defense-off-camera-press-briefing-by-vice-admiral-james-syring-on/.

[6] Prepared statement of Lt. General Samuel A. Greaves before the Strategic Forces Subcommittee of the Senate Armed Services Committee, March 22, 2018. Online at: https://www.mda.mil/global/documents/pdf/FY19_Written_Statement_SASC_SFS.pdf.

[7] Government Accountability Office, “Missile Defense: Some Progress Delivering Capabilities, but Challenges with Testing Transparency and Requirements Development Need to Be Addressed,”GAO-17-381, May 2017, p. 51. Online at: https://www.gao.gov/assets/690/685462.pdf.

[8] GAO-17-381, p. 51.

[9] James Drew and Jen Dimascio, “New Trajectory: As Pentagon Adds Dollars for Missile Defense, Raytheon Pitches SM-3s as ICBM Killers,” Aviation Week and Space Technology, October 16-29, 2017, p. 58.

[10] Drew and Dimascio, “New Trajectory.”

[11] Drew and Dimascio, “New Trajectory.”

[12] FY 2018 NDAA, section 1680.

[13] Government Accountability Office, “Missile Defense: The Warfighter and Decisionmakers Would Benefit from Better Communication about the Systems’ Capabilities and Limitations,”  GAO-18-324, May 2018, pp. 61-62.