What’s the Difference between a CE-I and CE-II EKV?
There are two variants of the Exo-atmospheric Kill Vehicle (EKV) currently deployed.
The first deployed version of the EKV is known as the Capability Enhancement-I, or CE-I, kill vehicle. The CE-I began deployment with the emplacement of the first GBI interceptor at Fort Greely, Alaska in July 2004. The last one was deployed in September 2007, at that time bringing the number of deployed GBIs to 24, all equipped with the CE-I.
Five CE-I EKVs have been expended in tests. These were used in a successful (non-intercept) flight test in December 2005, three reportedly successful intercept tests on September 1, 2006, September 28, 2007 and December 5, 2008, and a flight test (non-intercept) of a two stage version of the GBI booster on June 6, 2010. Assuming that none of the EKVs used in these tests were pulled off previously deployed GBIs, this indicates that at least 29 CE-Is were produced.
The Missile Defense Agency (MDA) began development of a new version of the EKV, the Capability Enhancement-II (CE-II), in 2005. The primary motivation for developing the new version was the obsolescence of parts in the original version, but a number of improvements were also made. GBIs equipped with the CE-II EKV began deployment in October, 2008. Ten of the thirty deployed GBIs currently have the CE-II version of the EKV.
The CE-II has been used in two intercept tests: FTG-06 on January 31, 2010 and its near-repeat FTG-06a on December 15, 2010. Both intercept attempts failed due to different problems with the kill vehicles. FTG-06 reportedly experienced a quality control failure in a thruster. (FTG-06 also experienced a radar failure, however, the kill vehicle had already acquired its target before this occurred.) The failure of FTG-06a was eventually attributed to a component failure in its guidance system. No non-intercept flight tests have been conducted with a CE-II EKV, thus at present the CE-II EKV has not been successfully flight tested.
Following the second CE-II test failure, MDA Director Lt. Gen. O’Reilly ordered further deliveries of EKVs to be suspended until the problem causing the failure was found, corrected and the EKV was successfully flight tested. In addition, the MDA announced that GBIs equipped with the CE-II would not be considered operational until after a successful flight test of the kill vehicle. According to the GAO, as of early 2011 when deliveries were suspended, 12 of 23 CE-IIs on order had already been delivered. These twelve would account for the ten deployed and the two used in tests. At this time the plan was for a total of 52 GBIs (it is now 57), including 30 deployed, with 16 for tests and 6 as spares. This is consistent with a total production of about 29 CE-Is.
MDA Director Lt. General Patrick O’Reilly has stated that the new version of the kill vehicle has “greater sensitivity and capability” and “more accurate guidance instrumentation”. According to vice chair of the Joint Chiefs of Staff, Gen, James Cartwright, the CE-II “gives us some things we didn’t have in the older version.” The CE-II apparently involves a new processor, an improved infrared seeker and a new or improved onboard discrimination capability.As of the beginning of 2012 (at which point CE-IIs had already been deployed for two years), two technologies developed for the CE-II, an upgraded infrared seeker and onboard discrimination, were assessed by the GAO as “only nearing maturity.”
 According to MDA Director Lt. Gen. Patrick O’Reilly, “However, we started a second version of the missile kill vehicle in 2005 based on obsolescence reasons; parts, manufacturers and so forth not producing parts anymore that – and the electronic systems that we needed.” Strategic Forces Subcommittee, House Armed Services Committee, March 31, 2011.
 U.S. General Accountability Office, “Missile Defense: Actions Needed to Improve Transparency and Accountability,” GA0-11-372, March 2011, p. 80.
 GAO, GAO-11-372, p. 87.
 Strategic Forces Subcommittee, House Armed Services Committee, March 31, 2011
 “Cartwright: U.S. Protected Against Missile Threats Despite Test Failure,” Inside Missile Defense, December 29, 2010.
 According to a GAO figure, the CE-II involves a “New processor.” U.S. General Accountability Office, “Defense Acquisitions: Production and Fielding of Missile Defense Components Continue with Less Testing and Validation Than Planned,” GAO-09-338, Figure 4 , p. 43.
 U.S. General Accountability Office, “Defense Acquisitions: Assessments of Selected Weapon Programs,” GAO-12-400SP, March 2012, p. 58.