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. 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. 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. 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.
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. 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.
 Jim Bennett, “The Kwajalein Hourglass,” September 26, 2000, pp. 1, 8.
 Stanley W. Kandebo, “NMD System Integrates New and Updated Components,” Aviation Week and Space Technology, March 3, 1997, pp. 47-51.
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.
 Kilikaukas, et.al., p. 75
 Military Electronics Briefing, “BMD X-Band Radars & BMD C4I,” Teal Group Corporation, July, 2007.
 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.