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by Tom Mahood

 
Lockheed Martin's Helendale RCS range, antenna array and operations complex; photo from October 2010 by Gary Sellani.Photo by Joshua Nyhus
 

Radar Ranges of the Mojave Desert

 

Helendale Avionics Facility - Lockheed Martin

Location

This facility is located on approximately 9 square miles (over 5,700 acres) of land, about 5 miles north of Helendale and just west of the Mojave River. It has a site address of 17452 Wheeler Road, Helendale CA 92342.

History and Property Ownership

This fairly new range, and most mechanically sophisticated of the ranges, was constructed as an initial phase in 1983 and expanded in 1985. Its official name is the Helendale Avionics Facility and is owned and operated by the Lockheed Martin Skunk Works.

At this time, Lockheed actually owns outright only one square mile, Section 33 of T9N, R4W, the parcel the majority of the range is on. Lockheed leases the remainder.

Lockheed first took control of Section 33 August 11, 1979, by means of a lease, with option to buy, from the previous owners, the Seino family. Officially however, the lease was not to Lockheed, but rather an attorney, J. Gregg Evans of Los Angeles. Evans apparently was a front for Lockheed in the transaction, and the previous owners may not have known who they were really dealing with. On July 20, 1981 the lease was recorded, omitting specific details. It wasn't until December 7, 1989 that Lockheed officially took title to the parcel by exercising their option to buy clause in the lease

The remaining 8 square miles making up the facility are owned by a division of Southern Pacific Land Company (The railroad people) called Catellus Development Corporation, located in San Francisco. The property came into Southern Pacific's hands on July 7, 1981, when it was granted ownership, by way of a patent, directly from the US government. Presumably, they immediately turned around and entered into a long term lease with Lockheed for these parcels.

There were two phases to the development of Lockheed's facility at Helendale, the first beginning in 1982, at a cost of $15-20 million. This first phase, becoming operational in October of 1983, was a relatively modest installation with target locations downrange 2,500' and 5,000' from the operations complex and antenna array. The overall length at the time was 5,500'.

The expansion of the Helendale facility to what it is today, or "HELEX, Phase 2," as it was known, began in early 1985 and was completed by the end of that year. The project was also known as the Area 20 range extension. This expansion lengthened the range to 8,200', added a new target position and built the massive concrete structure at the end of the range known as the "Upper Chamber." The plans were prepared in late 1984 by the H.K. Ferguson Company of San Francisco, a subsidiary of Morrison-Knudsen.

Facility Description

The orientation of this 8,200' long facility is north-south, with the centerline only a few hundred feet east of the east edge of the old Helendale airport (Figures 15 and 16). One of the three paved runways (4/22, 4,600' long) of the old airstrip is still maintained and operational, and has lighting for night operations.

Figure 15. Lockheed Martin Helendale RCS Facility, Aerial View from Target Support Area. (Photo by Tom Mahood.)

Figure 15. Lockheed Martin Helendale RCS
Facility, Aerial View from Target
Support Area. (Photo by Tom Mahood.)

Figure 16. Lockheed Martin Helendale RCS Facility, Aerial View from Antenna Array/Operations Area. (Photo by Tom Mahood.)

Figure 16. Lockheed Martin Helendale RCS
Facility, Aerial View from Antenna Array/Operations
Area. (Photo by Tom Mahood.)

At first glance, that fact that it is only a single range with just three target positions, might make one think this is a relatively simple installation. Quite the contrary is true. This is truly a remarkable facility with superbly clever engineering. We'll start our "tour" of the facility at the south end with the operations center, and proceed downrange (northward) from there.

The Operations Complex is the large cluster of buildings at the very south border of the property (Figure 17). Located here are the office and administrative areas, control rooms, data measurement facilities, hangars for model storage and maintenance (totaling 75,000 square feet), and a 150,000 gallon emergency water reservoir.

Figure 17. Lockheed Martin Helendale RCS Facility, Operations Area. (Photo by Tom Mahood.)

Figure 17. Lockheed Martin Helendale RCS
Facility, Operations Area. (Photo by Tom Mahood.)

On the north side of the Operations Complex is the Antenna Array. This 70' high tower holds a number of different radar antennas, covering a wide range of frequencies. Hydraulic elevators on the tower move the antennas up or down, to place them in optimum positions for any given test. According to the most recently released public information, the antennas are fed by a 1 kilowatt System Planning Corporation (SPC) MK III radar unit. However the SPC MK III is no longer a "state of the art" unit, now superceded by the SPC MK IV, which is currently the most widely used radar cross section measurement radar in the country. It's reasonable to assume the Helendale facility has upgraded to a MK IV unit by now. The MK V radar unit, which will use a Windows (!) control system, is about to enter prototype stage. (THC note: The current SPC instrumentation radar for RCS measurements is the Mark Ve; other radars currently in use in the facilities like the ones described here are the RadarMan™ system by Quarterbranch Technologies and the BlueMax™ by Star Dynamics.)

Extending north from the Antenna Array is the range itself. It is a 300' wide asphalt surface 3" thick, extending for the next 7,500' The surface is absolutely flat, with even the curvature of the earth removed. At least initially after construction, the surface was dusted with sand so that pilots wouldn't mistake it for a landing strip, and also to reduce radio wave distortion from heat shimmers.

Rather than trying to defeat the ground plane effect inherent in ground plane type radar ranges, this range has been designed to take advantage of the multipath bounce of the radar beam off the asphalted surface. This increases sensitivity by about 12 db.

Moving 1,400' downrange from the Antenna Array, we come to Antenna Pit 1. At this location, test objects can be placed upon four different mounts. The support may be either a 14' long metal or composite pylon, a foam column, or an inflated air column. The targets mounted at Pit 1 may be up to 14' in length and weigh up to 1,600 pounds. The targets here are placed upon the mount using either a crane or forklift.

Immediately uprange of Pit 1, visible on the surface of the range, is a long white metal cover. Under this cover is a hinged calibration pylon. Prior to testing a model at Pit 1, the calibration pylon is extended with a known, measured shape mounted on it. The technicians at the operations complex can then adjust and calibrate their equipment on the basis of a known shape. The calibration pylon is then retracted and an actual model measured.

Moving next to a point 5,000' from the antenna array, we come to Pit 2 (Figure 18). This 80' deep pit is covered by hinged white doors on the surface and contains a pylon extended by means of a hydraulic ram. Just beneath these doors, and above the retracted pylon is a small workroom in which models up to 50' in length and weighing up to 6,000 pounds may be mounted to the pylon. Immediately adjacent and uprange to Pit 2 is a much smaller pit containing a calibration shape mounted on a hinged pylon. It functions in the same manner as the calibration pit for Pit 1.

Figure 18. Helendale RCS Range, Test Pit 2. (Photo by Tom Mahood.)

Figure 18. Helendale RCS Range,
Test Pit 2. (Photo by Tom Mahood.)

This is pretty much the limit of the first phase of the facility at Helendale. But then in 1985, work began to extend the range and the major bells and whistles were put in.

A large 60' diameter mobile antenna on a crawler-type transporter was added 5,300' from the main antenna array. When not in use, the transporter moves the large dish antenna laterally, off to the west side of the range. This massive antenna required a specially constructed roadbed and bridge over a flood control channel. The antenna, known as MOBATS, is used for low frequency, high power RF measurements. This mobile crawler antenna seems to be a replacement for an antenna pit planned at the 5,400' point, but never implemented.

At the 7,300' mark, we come to a very long white metal cover in the surface of the range. Beneath it is another calibration pit (Area 50), the largest of the range at 130' long. As with the other calibration pylons, a simple methodology is used to raise it. The pylon is merely hinged at one end, and after the cover doors are opened, it is elevated from its horizontal resting position within a well to a near vertical position. Again in this case, its purpose is to place an object of known shape and size into the radar beam to calibrate the receiving equipment prior to actual model testing.

The jewel of the facility is found at the 7,500' point. This curious structure, in the depression at the far end of the range, is known as the "Upper Chamber" (or Area 30 during construction). Although it appears to be built of solid concrete, it is actually composed of concrete blocks. On the side of the structure with the vertical face, there is a large, side-sliding hangar door in the 40' high face of the structure. It is through this door that models are brought into the Upper Chamber.

Careful inspection of the Upper Chamber's roof reveals what appears to be a square cover, 80' on a side, with a split along a diagonal. This cover retracts on two sides, separating along the diagonal, exposing an 80' square opening into the Upper Chamber below. When closed, an air bag arrangement seals the diagonal seam.

Surprisingly, the useable area within the Upper Chamber is less than it appears when viewed from outside. Actual level floor space is only about 130' by 110', about 14,000 square feet. Most of the area apparently covered in concrete surrounding the Upper Chamber is actually covered slope. At the time of construction this area was not utilized and left as covered, but bare slope.

The area within the Upper Chamber is primarily a workroom and staging area (Figure 19). There is a large overhead traveling bridge hoist for the movement and manipulation of RCS models. There is also a diesel generator, a control room, restrooms and a small winch room off to one end. There are no office areas. The right rear portion of the Upper Chamber is dominated by the Silo and its cover.

Figure 19. Helendale RCS Range, Main Target Support Pylon. (Photo by Tom Mahood.)

Figure 19. Helendale RCS Range, Main Target
Support Pylon. (Photo by Tom Mahood.)

The Silo, also known as Area 35, is located directly beneath the floor of the Upper Chamber and takes up much of the useable floor space (Figure 20). It is a massive circular shaft with an inside diameter of 33', reaching a depth of 210' below the floor of the Upper Chamber. It is constructed of reinforced concrete with a minimum wall thickness of 3-1/2'. The upper walls of the Silo are a bit thicker. Construction of the Silo structure alone required in excess of 3,000 cubic yards of concrete to construct. That's the contents of about 300 fully loaded cement trucks, hence the local residents' tales of "cement trucks lined up for miles" during the facility's construction. The depth of the Silo puts it well below the water table of the adjacent Mojave River, and ensuring seepage water is constantly pumped out is a concern. There are some stories that the design of the Silo was based upon that of an underground Titan missile silo. If true, there was undoubtedly intense interest in the site from Soviet spy satellites during construction!

Figure 20. Helendale RCS Range, Upper Chamber and Pylon Silo.

Figure 20. Helendale RCS Range,
Upper Chamber and Pylon Silo.

Residing within the Silo is the retractable pylon upon which models are placed for raising into the radar beams for measurement. The pylon rests upon a counterbalanced hoist structure just beneath it, which is raised by a dual cable winch mechanism. In addition to a ladder, access is provided to various levels of the Silo by means of a small, Swedish made personnel elevator.

For testing, models (or even full sized aircraft) are brought into the Upper Chamber through the side sliding doors, raised by the bridge hoist, and placed over the tip of the pylon. After any necessary calibration, the roof of the Upper Chamber is opened and the pylon begins to rise. The pylon, which was upgraded in May, 1996 with a new, stealthier design (called a "Squareback Superskirt" by Lockheed), has the capability to move the model fore and aft 7' or rotate it 360 degrees, to help clear the opening in the roof of the Upper Chamber. The movement capabilities of the pylon are also used in the testing program.

When the pylon reaches full extension (Figure 21), hydraulic cylinders tilt the pylon forward to an angle of 55 degrees from horizontal and the roof may close beneath it. When fully raised in its normal tilted position, it can place a model or actual aircraft (weighing up to 30,000 pounds with dimensions up to 105' by 73') about 100' above the roof of the Upper Chamber.

Figure 21. Helendale RCS Range, Upper Chamber, Target Preparation Area, and Target Support
Pylon. (Photo by Tom Mahood.)

Figure 21. Helendale RCS Range, Upper Chamber,
Target Preparation Area, and Target Support
Pylon. (Photo by Tom Mahood.)

The silvery stretched pumpkin seed shape on the end of the main pylon, (and the shape on the pylon at Pit 2), is a "polecap". The Star, a company newspaper published by the Lockheed Martin Skunkworks, in the June 21, 1996 issue, ran a photo of the new pylon and polecap on its front page (Figure 22). The polecap is used during calibration of the main pylon. The shape of the pylon is so stealthy, that only the very tip of the pylon ends up being a significant source of signal return. To minimize this, a precisely shaped polecap is placed on the tip of the pylon to eliminate any radar returns from this spot. Then, once the very small return from the pylon is accurately determined and the system calibrated, the polecap is removed and a model put in its place. Perhaps surprisingly, the polecap was fabricated for Lockheed by a boat-building firm, Goetz Boats in Bristol, Rhode Island. It consists of aluminum honeycomb and carbon fiber, and the band along the outside edge is made of Kevlar, and the whole thing coated with RAM. After fabrication, it was shipped across country on a flatbed truck, looking to the world like the hull of a racing yacht.

Figure 22. Helendale RCS Range, Target Support Pylon with Low-RCS Polecap. (Lockheed Martin Photo.)

Figure 22. Helendale RCS Range, Target Support Pylon
with Low-RCS Polecap. (Lockheed Martin Photo.)

There are a few other facilities of note, located behind the Upper Chamber (or downrange) in relationship to the antenna array, on the original grade. The first of these is a fire pump house, also called Area 10. It's a small cement block structure near the edge of the depressed area. It contains a pump for emergency fire situations. Adjacent to the pump house is a small parking area with space for 20 cars. The small, dark colored rectangular area on the northeast side of the pump house is an emergency water reservoir (covered by a flexible membrane to keep out animals and dirt) for utilization by the pump house. Further downrange from that is a tower containing various instruments, the weather station mast.

Range Capabilities

The facility has the capability to test the complete frequency range from 120 MHz to 18 GHz, and a spot frequency of 35 GHz with four different signal polarizations.

Range Security

Test security is primarily provided by the unique ability to quickly remove models from sight by retracting the pylons underground. The facility itself is surrounded by a low fence, posted with "No Trespassing" signs. Lockheed security occasionally patrols the boundaries. Much of the land to the north and east is public, and development is occurring to the south, thus making discrete testing more difficult. This is alleviated somewhat by the ability to move models quickly out of sight.

Other Information

To construct their own facility, Lockheed used the knowledge gained from their construction of the RAMS facility they built for the Air Force at White Sands in New Mexico. This facility uses virtually the same design as RAMS and seems to have been built concurrently. Here is a photo of the RAMS site in New Mexico for comparison to the Helendale facility (Figure 23).

Figure 23. National RCS Test Facility (NRTF) RATSCAT Advanced Measurement Site (RAMS),
Holloman AFB. (USAF Photo.)

Figure 23. National RCS Test Facility (NRTF) RATSCAT
Advanced Measurement Site (RAMS),
Holloman AFB. (USAF Photo.)

A couple comments on the idea of this being an "underground base" or "Continuity of Government" facility: The aerial photos of this site were taken on June 15, 1996. Coincidentally, that day Lockheed Martin was having an Open House or Family Day (That was the reason I was able to obtain such interesting photos). A large number of people, including children, were observed on tours of the entire complex. They were shown within the Upper Chamber and the pylon raised and put through its paces. It's hardly likely that the facility would be thrown open for family tours were there anything truly secret or sinister there.

Lockheed Martin's Helendale Avionics Facility--antenna array and support and article preparation areas
Photo by Joshua Nyhus

Furthermore, I had the opportunity to review the construction plans for the facility and other than the unique engineering work for the facility itself, nothing was out of the ordinary. Certainly there are subsurface structures, but there is nothing that could even be remotely construed as a "base". The only deep underground components are the pylon wells, and they are filled with the pylons. The Upper Chamber, basically a covered excavation, is much more modest a facility than it appears to outside observers. This is an absolutely fascinating facility, but in its own right, not because of some idea that it is an "underground base".

Detail from Gary Sellani's panorama of the Helendale facility.
Photo by Gary Sellani

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Update:

Lockheed Martin has produced a short video on stealth technology which highlights the role of the Helendale RCS range in testing and measurements which dramatically advanced the state of the art:

In 2005, Lockheed Martin issued a press release and photographs of the X-47B Joint Unmanned Combat Air Systems (J-UCAS) RCS model being prepared for testing at Helendale:

Helendale RCS facility; testing of X-47B J-UCAS        Helendale RCS range; X-47B UAV model on RCS pylon.
Lockheed Martin Photos

Helendale RCS range: X-47B RCS model moved on a flatbed truck to the upper chamber area for installation on target support pylon.        Helendale RCS-Range: X-47B RCS model on pylon, ready to be raised to test height.
Northrop-Grumman Photos

See the Center for Land Use and Interpretation entry for the Helendale RCS Facility.

Updated satellite imagery of the Helendale facility is available at Virtualglobetrotting.com.

 
 

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