Are Boost Phase Defenses Making a Comeback at MDA? (August 21, 2013)

Recent Missile Defense Agency (MDA) presentations at the August 2013 Space and Missile Defense Symposium suggest that boost phase defenses may be making something of a comeback at the MDA.   This is somewhat surprising (to me), since in the last few years MDA has cancelled its two main boost program, the Kinetic Energy Interceptor in 2009 and the Airborne Laser in 2011.

However, a slide, shown below (click on it for a larger image), from MDA Director Vice Admiral J.D. Syring’s August 14 presentation showed an “Airborne Interceptor Layer” that was intended to provide “Highly mobile, survivable BMD; Autonomous and Integrated” as one of five MDA “Priority Technology Investments.”[1]  Another priority investment area was high power lasers, with one objective being the development and deployment a new Airborne Laser.



Another slide, shown below, from the presentation of  Richard Matlock, MDA’s Program Executive for Advanced Technology, shows both a “Boost Phase Kill” from a “High Altitude Long Endurance Platform” (apparently using a laser), and an “Airborne Weapons Layer,” deployed on a fighter aircraft.


[1]Slide 21 of VADM J. D. Syring, “Ballistic Missile Defense Overview,” 16th Annual Space and Missile Defense Symposium, August 14, 2013.

More on Early Warning Radar to Qatar (August 8, 2013)

In my post of August 7 about the U.S. sale of a large phased-array FPS-132 early warning radar to Qatar, I omitted the detail that the announcement stated that the radar was a Block 5 version of the FPS-132.  I omitted the “Block 5” designation because I has never seen this before and had no idea what it meant.  However, a 36(b)(1) Arms Sale Notification released today provides some additional information.

Specifically, the Notification says:

“The AN/FPS-132 Block 5 supports Missile Defense, Space Situational Awareness, and Missile Warning areas.  The Block 5 system employs 3 electronically steered phased array radar faces to survey 360 degree azimuth.  The Block 5 system is capable of reporting airborne tracks to a maximum range of up to 2,000 km and to a minimum radar cross section (RCS) of 1 m2.”


(1) It is a three-faced array (like the one at Fylingdales).  So its coverage is not solely focused on Iran , but will include the entire region.

(2) The description of it having a maximum range of 2,000 km and a minimum target RCS capability of 1 square meter:

                (a) Vastly understates the radar’s capabilities.  See my post of August 7 for a discussion of the range capabilities of at least the U.S. FPS-132s.


                (b) Indicates that the radar is a much smaller version  of the U.S. version of the FPS-132 (unlikely)


                (c) indicates that software restrictions are being installed in the radar to limit its capabilities.

If I had to guess, I’d guess it’s (a).

The 360° nature of the radar would make it even more attractive for space surveillance, assuming (as I am) that the U.S. will have access to its data.  It’s hard to see what the south looking face(s) of the radar would do other than look for space objects.   


Update on TPY-2 Radars. (August 8, 2013)

According to a recent report, the Army may have to “borrow” a TPY-2 X-band radar from a Terminal High-Altitude Area Defense (THAAD) battery for use in future missile defense tests.[1] 

This seems like a good occasion to take another look at where the United States is in building and deploying these radars.  In particular, a more detailed look at the current status of and potential future requirements for these radars indicates that substantially more than the currently planned twelve radars may be needed to meet requirements.


A TPY-2 radar and associated equpment at Kwajalein for the FTI-01 test (image source:

The TPY-2 radar is an air-transportable radar X-band radar (X-band refers to its operating frequency of about 10 GHz) that can be configured either as a forward-based radar (FBX) for detecting, tracking, and discriminating ballistic missile targets or as a fire control radar for a THAAD  theater missile defense battery.   A TPY-2 radar can be switched between the either configuration in no more than about eight hours.  As a forward deployed radar, a TPY-2 can be used simultaneously both as part of a regional defense system and, in some cases, as an element of the U.S. Ground-Based Midcourse (GMD) national missile defense system.

Prior to 2012, plans called for a total of 14 TPY-2 radars, nine of which were intended for THAAD batteries.  The FY 2013 MDA budget, released in February 2012, reduced the number of planned TPY-2s to eleven (corresponding to a decrease in the planned number of THAAD batteries from nine to six).  In 2013, Congress provided funding for a twelfth TPY-2. 

The U.S. Army has so far accepted delivery of eight TPY-2s.  A TPY-2 takes about 30 months to build under normal circumstances.  In March 2013, it was reported that TPY-2s numbers nine and ten were about halfway completed, and that construction of number eleven was just beginning.  TPY-2 #12 is not yet formally under contract.

Thus, in approximate order of deployment, the current status of the existing and currently planned TPY-2 radars is:

(1) Recently used for testing.  This is the oldest of the TPY-2s.

(2) FBX – Northern Japan

(3) FBX — Israel

(4) FBX — Turkey

(5) THAAD battery – now at Guam

(6) THAAD battery – now at Fort Bliss, TX

(7) FBX – Qatar

(8) THAAD battery #3 (in training) – Fort Bliss

(9) (~mid-2014) THAAD battery #4

(10) (~mid-2014) THAAD battery #5

(11) (~late-2015) THAAD battery #6

(12) (2016, not yet under construction) FBX #6

At present, then, all eight already-completed TPY-2 radars are committed, four as FBXs, three as THAAD radars, and one for use in testing.  At the very least a TPY-2 operating as an FBX will be needed for the FTO-01 integrated system test planned for later in 2013 (another TPY-2 will be used as THAAD fire control radar during this test). 

However, in February 2013 the U.S. announced that a second FBX would be deployed to Japan in the near future.  This commitment was reiterated at the March 15, 2013 Department of Defense Press Conference announcing plans to deploy fourteen additional GBI national missile defense interceptors in silos in Alaska.  Since it appears unlikely that the ninth TPY-2 will be available before mid-2014, once this second radar is deployed to Japan, it thus may become necessary for testing purpose to “borrow” one of the TPY-2s assigned to a THAAD battery.

In the somewhat longer term, it appears that more, and possibly many more, TPY-2s will be needed to meet DoD requirements. Missile Defense Agency (MDA) Director Admiral James Syring recently stated that he was working to find funding for  a seventh and possibly eighth THAAD battery (each of which would require a TPY-2).[2]  At least several additional TPY-2s also seem likely to be deployed as forward-based radars.  In September 2012, the Wall Street Journal reported that in addition to the second FBX to be deployed to Japan, the United States was evaluating potential sites, such as the Philippines, for a third FBX deployment to eastern Asia (see my post of September 27, 2012).  Given the limitations of the Aegis Ashore radars planned for Romania (by 2015) and Poland (by 2018), additional TPY-2s will also likely be needed for deployment in Europe.  The September 2012 National Academy of Science (NAS) Report stated that the MDA has proposed deploying a TPY-2 at both Aegis Ashore sites (although possibly this could be accomplished by deploying a THAAD battery to either or both sites).[3] 

In addition, four TPY-2s have been sold to Qatar and the United Arab Emirates (two each) as part of THAAD batteries.  Production of these radars may not yet begun, as the twelfth U.S. TPY-2 was funded by Congress earlier this year in part to prevent a temporary shutdown of the TPY-2 production line in FY 2014.  

Finally, the September 2012 NAS Report proposed the deployment of five new X-band radars for precision tracking and discrimination.  Each of these proposed radars would be built using two TPY-2 antennas stacked one on top of the other.  Five such stacked TPY-2 radars would thus consume production resources equivalent to ten TPY-2 radars.  A February 2013 MDA report stated that such a stacked TPY-2 radar would take 30 months to develop and produce “assuming that two existing radars were made available for testing and integration.”[4]  If two already existing radars were not made available (which seems unlikely given the short supply of such radars), at least 63 months would be required to build such a stacked TPY-2 radar, “based on current radar production times.”  The report estimated that a stacked TPY-2 would cost “at least $500 million.” While building such a network of stacked TPY-2 radars would clearly have a huge impact on TPY-2 production, they do not currently appear to currently be MDA’s preferred option for adding new radar capabilities, at least based on the MDA’s February 2013 report’s conclusion (presented without any supporting analysis) that “alternative concepts would provide a more robust capability for less cost.”


[1]Jen Judson, “Army Could Borrow THAAD AN/TPY-2 Radar for Future Missile Tests,” Inside Defense SITREP, July 22, 2013.

[2]Hearing of the Defense Subcommittee of the Senate Appropriations Committee, July 17, 2013.

[3] NAS Report, Page 273, Table E-42, note c.

[4] Missile Defense Agency, “Stacked AN/TPY-2 Array Concept Report to Congress,” February 2013.

U.S. to Sell Large Early Warning Radar to Qatar (August 7, 2013) (corrected February 10, 2014)

On July 29, the U.S. Defense Security Cooperation Agency notified Congress of a potential sale of an FPS-132 early warning radar to Qatar.  This sale of an early warning radar had been announced previously (see my post of November 7, 2012), but the type of radar was not specified at that time.  

 The cost of the radar and associated equipment, training and support was estimated to be $1.1 billion.


The FPS-132 UEWR radar at Fylingdales in Britain.  (Image source:

 The FPS-132 designation is used for Pave Paws or BMEWS early warning radars that have been upgraded to the Upgraded Early Warning Radar (UEWR) configuration that now forms the core radar infrastructure of the U.S. Ground-based Midcourse Defense (GMD) national missile defense system.  The GMD system currently incorporates three FPS-32s, the Pave Paws radar at Beale Air Force Base in California and the BMEWS radars in Fylingdales,  Britain and Thule, Greenland.   Current plans call for the two remaining Pave Paws radars, at Clear, Alaska and on Cape Cod, to be upgraded to the UEWR configuration by 2017 or later.

The three Pave Paws and two BMEWS radars, all manufactured by Raytheon, are nearly identical except for the somewhat greater size and power the BMEWS radars.  Each phased-array face of a Pave Paws radars has a diameter of 22.1 m compared to 25.6 m for a BMEWS’ radar face.   Each face of a Pave Paws is comprised of 1792 active transmit/receive (T/R) modules, giving an average power per face of about 150 kW.  Each face of a BMEWS includes 2,560 active T/R modules giving an average power of about 255 kW.   Except for the radar at Fylingdales, each of these radars has two faces, each of which covers 120° in azimuth, giving a total azimuthal coverage of 240°.  The Fylingdales radar has three faces, providing 360° coverage.   For descriptions of the Pave Paws and BMEWS radars, see my post of April 12, 2012.

These radars operate between 420-450 MHz, in the UHF radar band.  Because of their limited bandwidth (at most 30 MHZ, probably no more than 10 MHz), the range resolution of these radars is too poor (roughly 25 meters or more) to give them any significant discrimination capability.  However, they can simultaneously track large numbers of targets at large ranges.  MDA’s UEWR fact sheet states that an FPS-132 “detects objects out to 3,000 miles.” In fact, the actual ranges of these radars are likely to be significantly larger.  The original Pave Paws specifications state that it was capable of achieving a S/N = 17.7 dB (= 58.9) against a 10 m2 target (on boresite) at a range of 3,000 nautical miles ( = 5,550 km) with a single 16 ms pulse (the longest pulse it can produce).[1]   (However, because of the curvature of the Earth, ballistic missile targets are unlikely to be observed at ranges much greater than 4,000-4,500 km.) This corresponds to a range of 2,300 km against a 0.1 m2 target with a S/N = 13 dB (=20). The range of the larger BMEWS radars would be about 25% greater.  

The announcement of the sale of the radar to Qatar gives no details of the radar’s configuration, such as the number of antenna faces or how it compares in terms of size and power to the existing U.S. Pave Paws or BMEWS radars.  However, it seems likely that the radar is similar to the large phased-array early warning radar that Raytheon recently completed building for Taiwan (which in photographs such as the one here looks very much like a Pave Paws or BMEWS radar) and which is usually described as having two faces and costing about $1.3 billion (after significant cost overruns).

Qatar has also recently ordered two TPY-2 X-band radars (as part of two THAAD missile defense systems).    In the context of an integrated missile defense system, the FPS-132 UEWR would provide early warning and broad-area surveillance against ballistic missile targets for Qatar (and likely other countries), relieving the TPY-2 radars of this mission so as to enable them to focus on their roles as THAAD fire control and discrimination radars.

In U.S. use, all five of the Pave Paws and BMEWS radars also participate in the U.S. Space Surveillance Network (SSN).   While Qatar probably has little use for space surveillance, data from this radar (if made available) might be quite useful to the U.S. SSN, since it has no large radar in this part of the world.

[1] National Research Council, Radiation Intensity of the PAVE PAWS Radar System, 1979, Table 1.

CBO Estimates Cost of Moving GBR-P X-band Radar to U.S. East Coast (August 6, 2013)

A recent Congressional Budget Office (CBO) cost estimate has estimated the cost of upgrading and moving the Ground-Based Radar – Prototype (GBR-P) radar from Kwajalein to the U.S. East Coast at $510 million.  Such an upgrade and redeployment apparently is one option under consideration for adding an east coast X-band tracking and discrimination radar to the current U.S. Ground-Based Midcourse Defense (GMD) national missile defense system. 

The CBO estimated that upgrading the radar and buying communication equipment would cost $220 million.  The CBO did not indicate the nature of the upgrades that would be made.  The capability of the radar could vary greatly depending on the nature of the upgrades –see my post of June 11, 2013 for a discussion of some potential upgrade options).  The CBO additionally estimated that the preparing the site (assumed to be on an existing military base) and constructing facilities would cost another $290 million, bringing the total to $510 million.  The CBO estimated that the radar could be operational as early as 2017.  It further estimated that operating the radar through 2018 would cost an additional $140 million. 

The Ground Based Radar Prototype (GBR-P) is essentially a smaller version of Ground-Based Radar (GBR) proposed as the tracking and discrimination radar for President Clinton’s proposed3+3 NMD system.   No GBRs were ever built, but a single, similar radar was eventually deployed as the Sea-Based X-band (SBX) radar.  The GBR-P is located on Kwajalein atoll in the Marshall Islands in the Pacific Ocean, where it has been used in the past to observe U.S. ballistic missile tests, although it is not currently in use. Under President George W. Bush’s now-cancelled European Missile Defense plan, the GBR-P would have been moved to the Czech Republic and renamed the European Midcourse Radar.

Construction of the GBR-P on Kwajalein began in October 1996 and it was completed in September 1997.[1]  It first operated at full power in 1998. The GBR-P has an aperture of 123 m2, however only 105 m2 of the antenna is populated with its 16,896 T/R modules.[2]  These modules appear to be are 6 w peak power, 1.2 w average power, first generation T/R modules (see my post of June 4, 2012).  Its stated single-pulse detection range (against an unspecified target radar cross section) is 2,000 km.[3]  The radar sits on a large turntable that can be rotated ± 178° in azimuth and it’s boresite can be mechanically varied between elevations of  0° and 90°.  It has been reported that it can electronically scan its beam up to 25° (±12.5°) in both azimuth and elevation, although its actual electronic scan may be somewhat less.[4]

The GBR-P is designed to be upgradeable by adding more modules and using its entire 123 m2 aperture.  One source states that it can be upgraded to 78,848 modules.[5]  Another source (including authors from the radar’s builder, the Raytheon Company) says “The antenna was designed to be growable to greater than 50,000 elements.[6] 

[1] Jim Bennett, “The Kwajalein Hourglass,” September 26, 2000, pp. 1, 8.

[2] Stanley W. Kandebo, “NMD System Integrates New and Updated Components,” Aviation Week and Space Technology, March 3, 1997,  pp. 47-51.

[3]Michelle L. Kilikaukas, Dirk Brade, Robert M. Gravitz, David H. Hall, Martha L. Hoppus, Ronald L. Ketcham, Robert O. Lewis, and Michael L. Metz,  “Estimating V&V Resource Requirements and Schedule Impact,” Foundations for V&V in the 21st Century Workshop, Johns Hopkins Applied Physics Laboratory, October 22-24, 2002, p. 75;  MDA, “Information Report,” p. 9.

[4] Kilikaukas,, p. 75

[5] Military Electronics Briefing, “BMD X-Band Radars & BMD C4I,” Teal Group Corporation, July, 2007.

[6] J.F. Crawford, R. Reed, J.J. Hines, and D.R. Schmidt, “Ground-Based Radar – Prototype (GBR-P) Antenna,” National Conference on Antennas and Propagation, March 30-April 1, 1999 (IEE Conference Publication No. 461), pp. 249-252.