“Missile Defense. It’s Not a Game.” Actually, It Is. (May 28, 2012)

“MISSILE  DEFENSE. IT’S NOT A GAME” proclaims the front page of the “Careers” section of the Missile Defense Agency’s website. However, right below this pronouncement, you will indeed find a box inviting you  to:  MDA GAMES: CLICK HERE TO PLAY.


MDA’s Careers page.

Following the link takes you to the MDA’s game “The Interceptor,” which offers you the opportunity to “lead one of the greatest technological acheivements of our time.” ( I assume this refers to the missile defense system, not the game).  According to the company that produced the game, it was based on the old Atari “Missile Command” arcade game  and was aimed at “college students and recent graduates.”


The Interceptor


In order to win, you must get through four levels of play without letting a total of 40 missiles get through to the city you are defending.  Fortunately, the missiles are not nuclear-armed, as the city remains standing even after being hit by multiple missiles (although there are three large buildings in the foreground that do eventually fade away after enough hits).

My favorite feature of the game is that you can advance to the second level without destroying a single attacking missile.  (In fact, you don’t even have to fire a single interceptor to advance.)   If  you  remember Patriot in the 1991 Gulf War, you will appreciate this highly realistic feature.



A missile attack underway.

Space Surveillance Sensors: Haystack LRIR (May 25, 2012)

Haystack LRIR

The Haystack radar is large dish radar at the Lincoln Space Surveillance Center near Boston, and a contributing sensor to the U.S. Space Surveillance Network.[1]  From 1978 until April 2010, when it was shut down for a major upgrade to add a W-Band capability (which will be discussed in a future post), Haystack operated part-time as the X-Band Long-Range Imaging Radar (LRIR).  The LRIR was reportedly the only U.S. radar capable of imaging satellites out to geosynchronous orbit range.  The upgrade involved installing a new antenna and was due to be completed by about 2013, after which the radar will be known as the Haystack Ultrawideband Space Imaging Radar (HUSIR).  Under the upgrade, the LRIR’s X-band capability will be retained and is expected to return to operation in 2012.

September 2010: The top portion of the Haystack’s radome about to be reinstalled after the installation of the new antenna.  Photograph from MIT Lincoln Laboratory, 2010 Annual Report, p. 13.[2]


Ballistic Missile Defense: How Many GMD System Interceptors per Target? (May 23, 2012)


In March 2011, MDA Director Lt. Gen. Patrick O’Reilly told a House of Representatives hearing that “Today, 30 operational GBIs protect the United States against a medium ICBM raid size launched from current regional threats.”[1]  Leaving aside the fact the current Ground-Based Midcourse (GMD) system interceptors (GBIs) have never actually been tested against an ICBM target, this raises the question: How many attacking missiles comprise “a medium ICBM raid size” against the GMD system?  And this question then suggests the further question: How many GBI interceptors is the MDA planning to fire at each attacking missile?

This second question is particularly interesting in light of the recent MDA and DoD claims that they intended to modify already deploy GBI interceptors to “at least double” their effectiveness [see question 2 and its answer in May 21 post “A multiple choice quiz”].  This would seem to imply that the effectiveness of the current interceptors may not be too high.


A multiple-choice quiz to test your knowledge about the GMD system (you may notice a trend in the answers). (May 21, 2012)

The Ground-Based Midcourse (GMD) national missile defense system is intended to protect U.S territory from long-range missile attack, such as from intercontinental ballistic missiles (ICBMs) that might be built in the future by North Korea or Iran.  The system now deploys 30 Ground-Based Interceptors (GBIs) in silos in Alaska and California.  The first GBI was deployed in July 2004 and the first intercept test of using an operationally-configured GBI (that is one that is nominally the same as the deployed interceptors) was in September 2006.

Here‘s a simple multiple-choice quiz to test your knowledge about the GMD system (you may notice a trend in the answers).  Bear in mind that over the last decade numerous U.S. officials have stated the GMD system is already highly effective (“ninety percent plus” according to the Missile Defense Agency’s current Director — see the post of  April 27 on Thirteen Claims about GMD Effectiveness for details).

 (1) How many (percent) of the GMD flight tests have revealed problems that required subsequent modifications to the GBI interceptors?

(a) 20%.

(b) 50%.

(c) 70%.

(d) Every one.


Illustration of Radar Imaging of Satellite (May 20, 2012)

Recently published test range images provide an interesting illustration of U.S. capabilities to image satellites.

By combining range and Doppler measurements, wide-bandwidth radars can produce photograph-like images of satellites.  The range resolution of a radar is limited to about c/2β, where c is the speed of light and β is the radar’s bandwidth, although for radar processing reasons this limit is not always achieved.  For example, for β = 1 GHz, such as is used by the X-Band Haystack Long-Range Imaging Radar (LRIR)  (and the U.S. X-Band missile defense radars), this formula gives a range resolution of 15 cm, although the Haystack LRIR reportedly only achieves a resolution of 25 cm.  A small cross-range resolution can then achieved by observing a target as it rotates relative to the radar.  This rotational motion can be either due to the satellite’s own spin or simply due its orbital motion relative to the radar.   Typically a rotation of a few degrees is required to get a cross-range resolution equal to the range resolution. 

All U.S. radar images of real satellites are officially classified (although two apparently from HAVE STARE have been published on the internet).

However, the recently published 2011 Lincoln Laboratory Annual Report contains two images of a satellite model at a test range, corresponding to the resolutions of the Millimeter Wave (MMW) radar at Kwajalein before and after its upgrade from 2 GHz bandwidth (12 cm resolution) to 4 GHz Bandwidth (6 cm resolution).  The previous year’s Annual Report contained similar images for the Haystack LRIR at 1 GHz (25 cm resolution) and after its planned upgrade to 8 GHz (~ 3 cm resolution).  I have combined these to give a progression of improving resolution:


Here is a picture of the model used for the Haystack measurements (from the 1010 Annual Report):


 It is not clear that the same model is used for both the Haystack , as its relative dimensons appear different in the two sets of images (although this could be a viewing angle effect).  Nevertheless it provides an intersting illustration of the rapidly improving U.S. capabilities in this area  (although the last two images don’t look very different to me).

Space Surveillance Sensors: ALCOR Radar (May 17, 2012)


ALCOR (ARPA Lincoln C-Band Observables Radar) was the world’s first high-power long-range wide-band radar.[1]  It played a key role in the development and early implementation of range-Doppler techniques for imaging satellites, producing images with a resolution of 0.5 meters (about 20 inches). ALCOR began operations at Kwajalein in late 1969.  Although it has since been exceeded in both range and resolution capabilities by the Millimeter Wave (MMW) Radar at the same Kwajalein site (and by other wide-band radars at other sites), it remains an important collateral sensor in the Space Surveillance Network.[2]  


 The ALCOR antenna viewed from behind inside its radome at Kwajalein. (Photograph from Camp, et.al.,  Lincoln Laboratory Journal)


Graph of GMD Tests (May 14, 2012)

This post is an attempt at  a graphical depiction of the GMD testing schedule.  Information on future tests is as complete as the information I can find, but is certainly incomplete.  I will update this as I get more information.  Click on the images to make them more readable.

Each row of the table shows the tests that have taken place at that time and projected future tests.  The first three rows are for mid-2009, mid-2010, and mid 2011, respectively.  The fourth row is current as of about March 2012.



Space Surveillance Sensors: The ALTAIR Radar (May 11, 2012)

pALTAIR (ARPA Long-Range Tracking and Instrumentation Radar) is a large steerable dish-array radar at the U.S. ballistic missile test range on Kwajalein in the Pacific Ocean.[1]  Operating at both VHF and UHF frequencies, it is an important collateral sensor in the U.S. Space Surveillance Network, particularly for detecting and tracking newly-launched satellites and for tracking objects in deep-space and geosynchronous orbits.  Together with the Millstone Hill and GLOBUS II radars, ALTAIR provides complete coverage of the geosynchronous belt.


The four SSN radars at Kwajalein.  The ALTAIR antenna is the large dish at upper center, viewed partially against the lagoon.  The antenna for TRADEX, which backs up ALTAIR in the Space Surveillance Network (SSN), is the dish antenna on top of the building near the center of the picture.  The antenna for the ALCOR imaging radar is in the dome at lower left, and the antenna for the MMW imaging radar is in the dome in the center of the picture between the ALTAIR and TRADEX antennas.  (Photograph from http://www.orbitaldebris.jsc.nasa.gov/measure/radar.html.)


GMD Flight Tests of Operationally-Configured Interceptors (May 9, 2012)

GMD Flight Tests of Operationally-Configured Interceptors of the Ground-Based Midcourse Defense (GMD) national missile defense system.

(Update added 12/28/2012: FTG-17, listed below as taking place in FY 2016, has been delayed until 4Q FY 2019.  It will be an intercept test of a two-stage GBI against an ICBM target.  SASC 4/13/2011, p. 244).

The have been seven flight tests (five intercept attempts) of operationally configured GBI interceptors so far.  These are briefly described below, along planned future tests as best as I can figure these out. I will update as I get more information.

FT-1, December 12 2005.  First flight test of operationally-configured GBI, more than a year after the first one was deployed.  It was the first flight of the CE-I version of EKV.  It was not an intercept test; the target was computer-simulated.  Test was reportedly successful.


Space Surveillance Sensors: The Millstone Hill Radar (May 5, 2012)

The Millstone Hill Radar

The Millstone Hill Radar (MHR) is a large (84 foot diameter) L-Band dish tracking radar located, appropriately enough, on Millstone Hill in Westford MA, a suburb of Boston (42.62˚ N, 71.49˚ W).[1]  It is an important contributing sensor in the Space Surveillance Network (SSN) and is used both for near- and deep-space surveillance.  Two other SSN contributing sensors, the Haystack Radar and the Haystack Auxiliary Radar, which are primarily imaging radars, are located at essentially the same site, and all three are operated by Lincoln Laboratories.  The MHR should not be confused with two other radars at the same site and sometimes also referred to as Millstone Hill radars, one with a 220 foot fixed zenith-pointing antenna and the other with a 150 steerable dish antenna.  Both of these radars operate in the UHF Band and are used almost exclusively for scientific (ionospheric) research, although the steerable dish serves as a backup to MHR for space surveillance purposes.