Saturday, January 5, 2008

US Restricted and Classified Test Sites


The widespread availability of open-source overhead imagery thanks to applications like Google Earth and NASA World Wind has provided the public with the chance to view many restricted and classified test locations within the United States. While details of the test programs associated with some of these facilities are obviously not going to be discernable, the availability of open-source imagery nevertheless allows individuals to view sensitive facilities that normally would be hidden by terrain, and sometimes heavy security.

This article is not intended to be an all-inclusive list of classified test facilities, nor an in-depth examination of Area 51, but rather an overview of some of the most significant and interesting test sites in the country.


Some of the most significant defense-related facilities in the United States are Radar Cross Section (RCS) test ranges. These facilities, being either contractor or government operated, conduct some of the most sensitive test programs in the defense industry. RCS ranges are used to test the radar signatures of various objects, most significantly with the aim of measuring their ability to evade radar detection against various radar types. Stealth platforms like the HAVE BLUE were tested at an RCS range in order to validate the design before flight testing, for example, to ensure that the RCS of the aircraft would meet the requirements of the test program. Due to the sensitive nature of the testing conducted at these facilities, they are typically located in isolated areas.

The primary outdoor RCS test ranges can be located at the following coordinates:

Boardman: 45°44'53.55"N 119°47'10.02"W
Grey Butte: 34°34'13.01"N 117°40'11.27"W
Helendale: 34°49'30.40"N 117°17'45.83"W
Junction Ranch: 36°02'15.81"N 117°30'10.69"W
Kirtland AFB: 34°57'33.77"N 106°29'59.27"W
RATSCAT: 33°10'59.71"N 106°34'23.81"W
Tejon: 34°55'27.49"N 118°31'44.76"W

The following image depicts the relative locations of the various outdoor RCS test ranges listed above:


Located in an isolated area west of Boardman, Oregon, the Boardman RCS range is owned and operated by Boeing. The facility consists of a radar array at the west end and a pylon for mounting test articles at the east end. The pylon can be covered by a large, moveable hangar, to protect sensitive test objects from view. When RCS testing is ongoing, the hangar slides out of the field of view of the radar sensors on a set of rails. The sliding shelter concept is similar to what was used at the former Grey Butte RCS test range.

The following image depicts the Boeing Boardman RCS test range:

Grey Butte

The former Grey Butte RCS test range is located 25 miles south by southeast of Edwards AFB in California. The Grey Butte facility was operated by McDonnell Douglas in the past, before being acquired by Boeing when the two companies merged. In 1999 the facility was closed down, being sold to General Atomics, who currently uses the facility to conduct UAV research. The former RCS test range consisted of a primary antenna array at the west end, with various target positions scattered around the range. The primary RCS test article position was directly east of the antenna array, and was hidden by a retractable hangar, which may have inspired Boeing to use a similar system at their Boardman facility.

The Grey Butte facility is interesting insofar as the location of the aforementioned retractable hangar is concerned. At the Boardman facility, the hangar retracts southeast to place the structure outside the field of view of the radar being used to measure the test article's signature. In the Grey Butte facility, the hangar retracted directly aft of the test article's location. This is interesting because it would seem to indicate that the hangar was still within the field of view of the radar arrays targeting the test article. There are two possible explanations for this apparent discrepancy. First, radar sets with a very narrow beamwidth may have been employed. This would have allowed them to target the RCS test article, with any extraneous radar energy simply passing it by and travelling straight through the open hangar bay. The second possibility is more abstract, and far less likely, although it does raise some interesting questions. It is known that the Russian defense industry has been experimenting with ionized plasma as an RCS-reduction method. A similar system (or some other RCS-reduction method) could, in theory, have been employed at Grey Butte to hide the hangar structure.

The following annotated image depicts the former Grey Butte RCS test range:


Lockheed Martin's Helendale RCS test range, situated 32 miles east by southeast of Edwards AFB, is one of the most storied RCS test ranges in the country. The range area consists of an antenna array at the southern end, with two secondary target positions situated 425 meters and 1520 meters downrange. The primary test article facility is a large structure situated 2300 meters from the radar array. This is a large, underground complex, with a sliding roof hiding the retractable primary test pylon. A mobile radar antenna is also present, which moves off to the west when not in use to allow the radar sensors to the south a clear field of view to measure the primary test article.

The following annotated image depicts Lockheed-Martin's Helendale RCS test range:


The Tejon RCS test range is owned and operated by Northrop-Grumman (previously Northrop, before the merger). Located 35 miles west of Edwards AFB, the Tejon RCS range consists of two separate, co-located facilities. The older, larger north complex features an antenna array and four target positions, while the newer south complex features two separate antenna-target combinations.

The following annotated image depicts Northrop-Grumman's Tejon RCS test range:

Not all RCS test ranges are operated by private contractors. The US DoD operates three outdoor RCS test ranges in California and New Mexico.

Junction Ranch

The Junction Ranch RCS test range is operated by the US Navy. It is situated on the massive China Lake range complex, located 27 miles north by northeast of China Lake NWC.

The following annotated image provides an overview of the USN's Junction Ranch RCS test range:

Being a US Navy complex, the Junction Ranch RCS range has a few unique features. Firstly, there are two separate test sites. The "dry" site is a conventional RCS test range employing a radar array and pole-mounted test objects.

The following annotated image depicts the "dry" RCS test range at Junction Ranch:

The second range is unique in that it is a "wet" facility, designed to test replicas of seagoing objects which are mounted in a water pool. Three miles to the southeast a radar facility is located atop the surrounding mountains to enable RCS testing of objects placed in the pool. Both of these locations are depicted in the overview image above.


The RATSCAT Advanced Measurement System (RAMS) site is located 35 miles northwest of Holloman AFB, New Mexico. RAMS represents the most advanced low-RCS test range in the country, and as such is isolated in the White Sands Missile Range. Holloman AFB is also home to various other RCS test facilities operating under the direction of the National RCS Test Facility, with the capability to measure both pole models and in-flight models or aircraft.

The following image depicts the RATSCAT Advanced Measurement System site:

Kirtland AFB

Kirtland AFB in Albuquerqe, New Mexico is also the home to an unidentified RCS test facility. Some sources indicate that the facility may be associated with the Sandia National Laboratory, which also operates some facilities on the Kirtland range.

The following image depicts the RCS test range located on the Kirtland AFB range:

There are two other significant outdoor RCS facilities visible in the United States. They are associated with one of the most secretive military installations on the planet.


Area 51, also known as Groom Lake, Watertown Strip, Dreamland, or The Ranch, is one of the US government's most highly classified test facilities. The activities which take place at Area 51 are some of the military's most sensitive test programs, and have included the flight testing of the U-2, the A-12, and the HAVE BLUE stealth technology demonstrator.

The following image provides an overview of the expansive Area 51 complex:

Area 51 is home to some unique structures, both historical and current. The original AQUATONE and OXCART hangars can still be seen, with the OXCART hangars likely having served as the home to the RED HAT aircraft. The 24,000 foot runway, the longest in the world, is still present as well, but this is believed to no logner be operational, as denoted by the X markings on the northern end and the fact that the new runway uses the same numbers.

The following annotated image depicts some of the most interesting and significant facilities located at Area 51:

Various test facilities are located at Area 51. The location where the A-12 was pole-mounted for RCS testing can still be seen adjacent to the lakebed's western edge. The DYCOMS radar sensor system can also be seen. DYCOMS is an airborne RCS test system used to evaluate the radar signatures of aircraft which overfly the facility.

The following annotated image depicts Area 51's DYCOMS RCS test facility:

A facility which has been referred to as the QUICK KILL radar site is also present adjacent to the DYCOMS facility. The terminology may indicate that this is an electromagnetic weapon of some sort, designed to disable electronic systems.

Area 51 is not the only significant test site in the Nevada Desert. Some of them, by nature, may even be more secretive.


Located near Tonopah Test Range, the former home of the then-classified SENIOR TREND fleet, is an expansive complex housing what may be some of the most secretive items in the United States. A vast electronic combat range containing numerous radar systems is home to more than a few examples of Soviet and Russian radar systems. While their presence may be an open secret, as it has been stated in the past that the OXCART was tested against Soviet radar systems, the means of their acquisition is understandably highly classified. One can speculate that some systems may have been sourced from cash-strapped former Soviet republics, in the same manner that Moldova's MiG-29 fleet was acquired.

The following annotated image provides an overview of the most prominent features of the Tonopah Electronic Combat Range:

Not all of the radar systems present at the Tonopah site can be identified, due to the resolution of the imagery, and some of them may not even be radar systems at all. However, some of the radars are readily identifiable due to their large size. Situated around what appears to be the primary facility are four raised berms, each appearing to house a radar system. The northern and eastern berms are home to Soviet-era P-35 (BAR LOCK) E/F band EW radars. Just south of the main facility is another pad which appears to house an RSN-125 (LOW BLOW) engagement radar associated with the S-125 (SA-3 GOA) SAM system.

The following annotated image depicts the main test area at the Tonopah Electronic Combat Range:


The radar range near Tonopah is not the only electronic combat facility in the Nevada desert. At 37°18'58.48"N 116°46'50.93"W the Tolicha Peak Electronic Combat Range can be found.

The following annotated image provides an overview of the most prominent features of the Tolicha Peak Electronic Combat Range:

The mainstream belief is that the Tolicha Peak facility houses numerous radar systems to support RED FLAG operations, given its proximity to two mock airfields. A more detailed examination provides an alternative, that of foreign SAM system exploitation and testing. Elements of S-125 (SA-3 GOA), S-200 (SA-5 GAMMON), and S-300PS (SA-10B GRUMBLE) SAM systems can be found on the grounds of Tolicha Peak.

The following annotated image depicts what is likely an S-125 facility at Tolicha Peak. The object to the west of the RSN-125 (LOW BLOW) radar system would appear to be some sort of three-round launcher, or an unusual radar system, and does not resemble the 5P71 or 5P73 launchers found at operational S-125 sites around the globe, and as such may be some sort of dedicated test equipment.

The following annotated image depicts an S-200 launch site at Tolicha Peak. There would appear to be a second missile, albeit with the control surfaces removed, nearby. The 5N62 (SQUARE PAIR) engagement radar is not colocated with the launch facility and was not readily identified, but the facility 0.47 kilometers to the southwest is a candidate.

The most interesting facility found at Tolicha Peak is the S-300P launch site. It would appear that a nearly complete collection of radars is present, as well as two TELs and a 40V6 mast assembly. The 40V6 is used to mount either the 5N63S (FLAP LID) engagement radar or the 76N6 (CLAM SHELL) low altitude detection radar on a 23.8 meter mast to provide better performance in areas with varied terrain or vegetation. The shadow cast by the southern 5P85 TEL seems to indicate that it is a 5P85S, complete with the control compartment for controlling the adjacent 5P85D TEL. The vehicle which is most likely the 5N63S engagement radar vehicle appears to have the radar array lowered in the travel configuration. Given the presence of the mobile TELs and the mobile 5N63S radar, the system present here is likely either an S-300PS or export-standard S-300PMU.

The following annotated image depicts the Tolicha Peak S-300PS facility:

Close examination of the terrain in the vicinity of the Tolicha Peak Electronic Combat Range would seem to display impact craters, providing further evidence that actual SAM firings may be taking place here. As the United States does not actively list any of the aforementioned SAM systems in its operational inventory, it is likely that some sort of test work does take place here. It is also possible that the associated radar systems are in fact also used against aircraft flying on the Nellis AFB Range to provide more realistic electronic combat training.


Jackass Flats is situated 45 miles southeast of the Tolicha Peak Electronic Combat Range, and was the home to some of the most interesting experimental programs to be conducted in the Nevada desert.


Located on the eastern portion of Jackass Flats is the remains of one of the most interesting and potentially catastrophically dangerous weapons programs of the Cold War. Project Pluto was intended to culminate with the development of a nuclear powered cruise missile. A facility was constructed to test conceptual nuclear engine designs for Project Pluto. The vast facility consisted of three main areas. Firstly, there was a reactor assembly building where the Tory-series reactors were constructed and then disassembled for analysis post-firing. Secondly, there was a separate reactor test facility situated 2 miles from the assembly facility, where the test firings would occur. Lastly, there was a complex consisting of 25 miles of piping designed to provide the compressed air necessary for testing the reactor, as it was intended to operate as a ramjet and could not function with still air. Current imagery indicates that the piping has since been removed, but the structures remain, as does the railway which used an automated railcar to transport the test articles between the two facilities.

The following annotated image depicts the Project Pluto facilities at Jackass Flats:


Jackass Flats was home to a second nuclear-related test. The High Energy Neutron Reaction Experiment (HENRE) program used a linear accelerator to provide neutrons which would be used in a radiation measurement test program. The 1,527 foot tower used in the HENRE program was previously a resident of the Yucca Flat test area, and was employed in the BREN program. It was relocated to Jackass Flats to support the HENRE program in 1966.

The following image depicts the HENRE test tower at Jackass Flats:


The Nuclear Rocket Development Site (NRDS) at Jackass Flats was used to test nuclear rocket engines under the auspices of various test programs. The facility consisted of numerous structures, including the Reactor Maintenance, Assembly, and Disassembly (R-MAD) and Engine Maintenance, Assembly, and Disassembly (E-MAD) stations. There were three test stands, Test Cell A, Test Cell C, and Engine Test Stand 1 (ETS-1). Rocket engines, much like those tested at the Pluto facility, were transported using an automated rail system.

The following annotated image provides an overview of the NRDS:

Test Cell A was the location for the Kiwi-TNT destructive test which consisted of the obliteration of a nuclear rocket engine to simulate a potential accident during launch of a nuclear-powered rocket.

The following annotated image depicts one of the engine transportation railcars remaining at the E-MAD facility:


Radar Ranges of the Mojave
Gray Butte Radar Cross-Section Facility
Building Map of Area 51
RCS Ranges
The HENRE Program
Project Pluto
The NRDS (PDF file)
More on the NRDS (PDF file)

-All overhead imagery provided courtesy of Google Earth, Microsoft Virtual Earth, and NASA World Wind. USGS imagery was provided by the latter two sources.

-All information contained in this article is sourced from the public domain, principally the World Wide Web, and is not intended to imply the dissemination of, nor does it contain, restricted or classified material.

-For more information on NASA's World Wind application, reference the following: LINK


ELP said...

As always; great reading and very informative!

Faruq said...

Do u think you wil get a visit from Homeland Security because of this article? :P

Just kiddin good stuff!

Sean O'Connor said...


Hey, if you liked that, you'll love what I have coming!

Arthur said...

Great stuff, Sean. Never knew this much was out in the open on RCS facilities. Do you happen to know if there still are any facilities operational with the Rome Laboratories in NY?

jhowland said...


The AFRL Rome Lab range is still very busy. (Google AFRL Newport Research Facility.) We did some work there along with Lockheed/Sanders (now BAE) in support of the F-22 in the 90's, and I know that the AFRL has had an F-35 up on the tower recently. Don't know how much RCS/signature measurement they do at that facility, but they do a lot of antenna & EMC work there.


calvinb1nav said...

In the TPECR.jpg picture, judging by the shadows, the radar to the right of the SA-5 is a Square Pair, the next one some sort of Height Finder radar (probably ODD NET/SIDE NET/ODD GROUP), and the next one is a Tall King, all associated with the SA-5. Great site by the way!!!!

Anonymous said...

There is another potential RCS Test range just southwest of Walnut Springs, TX that may be associated with the Stephenville sightings about a month ago. This would be within flight range of the AF Plant #4 and other bases in TX. Check it out at:

32° 1'10.32" N 97°41'19.69" W

Anonymous said...

Just a note: KIWI-TNT took place at test cell "C" not "A" as reported above.

Gridlock said...

General Atomics now use the ex-Boeing RCS for UAV work then, eh?

Wonder what they could possibly be testing there..

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