Fylingdales on the North Yorkshire Moors National Park has been the home of a US Ballistic Missile Early Warning System (BMEWS) since the Cold War days of the 1960s. The base is run for the US by the RAF and is one of the 3 stations in a chain linked across the North Atlantic. The other stations are Thule in Greenland - operated by the 12th Space Warning Squadron (or SWS) and Clear in Alaska - operated by the 13th SWS – both components of the USAF 21st Space Wing based at Peterson Air Force Base in Colorado Springs.

The first choice for the UK BMEWS station was in fact Prestwick in Scotland. However, according to a 1959 Report on the State Department negotiations in Aviation Week, the British were reluctant to allow it because it was heavily populated area that would become a prime target in time of war. They were concerned about public protest. [1]

It is clear that the site at Fylingdales was eventually chosen because it is remote from areas of large scale habitation and also fulfils the stated requirements of:

• a high location with an unobstructed view of horizon;
• being situated in a local depression and away from the sea to reduce the risk of jamming or sabotage.

Under the BMEWS agreement, signed by the then Secretary for Air in 1960, the USAF own and supply the radar, computer and communications equipment and the UK provide the site, power and housing and its own communications requirements and pays for most of the maintenance and operation. Fylingdales was built in 1964 on Ministry of Defence land in the North York Moors National Park. It cost £46 million, £35 million of which was US dollars.

RAF Fylingdales originally consisted of three white spherical radomes (or “golfballs”) 43 metres in diameter. Each radome housed and protected a large radar dish that could be mechanically steered to search for intercontinental ballistic missiles that threatened the North American Continent from the USSR. Two of the dishes tracked from side to side, one at an elevation of 2.5^o and the other at 5^o above the horizon. Targets found at 2.5^o and then at 5^o could be a rocket in its boost phase and its trajectory would be tracked by the third radar to determine the point of impact.

At this time an uneasy balance of strategic nuclear weapons was held between the two super powers by setting an agreed limit to each side’s ability to counter a full-scale nuclear attack. In this way, any nuclear first strike would risk Mutually Assured Destruction (a MAD idea in more ways than one). The Anti-Ballistic Missile Treaty (ABMT), signed in 1972 by the US and USSR, set limits on the anti-ballistic systems (missiles and radars) that could be deployed by each side.

Fylingdales operates under the US "Masterplan for tactical Warning and Attack" which lists the aims of BMEWS as being to:

1. Support and aid the survival of strategic military forces.
2. Provide an accurate basis for (US) national command authority response decisions.
3. Enhance warfighting effectiveness of the strategic nuclear forces.

As well as its Early Warning Function, Fylingdales also forms part of the Space Surveillance Network (SSN), an intelligence network that tracks and maintains a database of space objects (military and civilian satellites and space debris).

Fylingdales is therefore a significant command, control, communications and intelligence installation. Information gathered by the radar installation is fed directly to the North American Aerospace Defense Command (NORAD) in Cheyenne Mountain, Colorado. From there information is passed to the National Command authorities and to Headquarters, Strategic Air Command (SAC). In time of war, it would provide the US President with information on what has and has not been attacked, monitor trajectories of both surveillance satellites and incoming ballistic missiles and allow prioritising and accurate response and targeting on "enemy" satellites and ballistic missiles.

False Alarms

Despite the "state of the art" technology installed at Fylingdales, there have been a number of false alarms. A flock of geese and (on 5th October, 1960) the rising moon (at Thule) have been mistaken for incoming missiles only on last minute checks was the firing of several missiles avoided. On 24th November, 1961 all communication links went dead between SAC HQ and the three BMEWS sites. Was it enemy action, or the coincidental failure of all the communication systems? All SAC bases in U.S. were alerted and B-52 nuclear bomber crews started their engines. Eventually, radio communication was established with a B-52 on airborne alert near Thule. It contacted the BMEWS station by radio and could report that no attack had taken place. The reason for the "coincidental" failure was that the redundant routes for telephone and telegraph between NORAD and SAC HQ all ran through one relay station in Colorado. At that relay station a motor had overheated and caused interruption of all the lines.

In 1979 a full alert was sounded when a ‘War Games’ simulation tape was loaded by mistake into NORAD computers. Fylingdales warned that a salvo of missiles had been launched against B52 bases from a Soviet submarine in the Pacific. ‘Things got very tense’. But no radar targets appeared in the ‘threat azimuth’ (the angles of the horizon at which a Soviet missile would normally be launched to attack Europe or North America). Details of this error are only known because a reporter witnessed the late stages of alert in a Virginia Air Traffic Control Centre and asked questions.

Past Upgrades

1979 - amendment to the 1960 agreement allowed a further $1.9 million contract to modernise the tactical operations room to help provide (in conjunction with Defense Support early warning satellites) a Tactical Warning/Attack Assessment directly to the US Joint Chiefs of Staff. The contract was awarded to RCA in June 1979.

1989 - 1992 – it was announced in 1985 that the three giant golfballs were to be replaced by a Large Phased Array Radar (LPAR) in the form of a 40-meter high, truncated pyramid. Each of the 3 faces of the pyramid contains an array of 2,560 aerials, transmitting at 420-450 MHz with a total mean power output of 2.5 Megawatts. It was to cost around £200 million, of which the US would pay 70% (for the radar technology) and the UK 30% (for the operating infrastructure). This contract was awarded to Raytheon - who also upgraded Thule in 1987. Work started August 1989 and the new system became operational in October 1992.

Limited by the conditions of the ABMT, the upgraded radar has a similar output power and the same 3000 mile range as the old one, but is able to operate over a full 360^o, rather than 120^o.

In addition, CND has always argued that this upgrade was a step towards the implementation of Ronald Reagan’s “Star Wars” idea – and that it was in contravention of the ABM Treaty which did not allow the construction of new radars of this type outside the boundaries of the US and USSR.

Environmental Concerns

In a letter concerning the 1989 upgrade sent to the Chair of the Leeds City Council Peace and Emergency Planning Committee on 10th October 1986, M. Webster of the North York Moors National Park states:

“.. the present installation at Fylingdales and the proposed modernization are both considered totally incompatible with the National Park, and that Committee deeply regrets the proposal to develop the modernized BMEWS at Fylingdales ”

The letter continues, with “the Committee asks … [that] …the government seeks to ensure that in the event of any future modernization being necessary that it is then possible to relocate BMEWS outside the National Park on environmental grounds.”

There is no evidence that any government since then has ever given this any serious consideration.

Health Effects

After the LPAR upgrade, in 1993, an ElectroMagnetic Radiation (EMR) Survey of the area surrounding Fylingdales was commissioned by the Nuclear Free Local Authorities [2] .

The survey was an extension of an earlier report produced in the summer of 1991 and used 23 measurement sites, including moorland paths and tracks, roadside locations and habitations. The survey found maximum field values of about 10Vm^-1 with typical values around 5Vm^-1.

The report concludes:

• “At no point in the area accessed by the survey is the field strength due to to RAF Fylingdales’ transmission higher than that recommended in the current UK guidelines for protection against biological hazard from non-ionizing radiation
• In the northerly locations, the new phased array radar has not significantly changed the time averaged levels of field to which walkers and residents are exposed;
  
• South of the transmitter, the levels to which walkers and residents are exposed are now ten times that which they were before the pyramid upgrade became operational;
  
• The threat to vehicles using the A169 from interference to their electronic control systems has been reduced though not eliminated.”

International Standards

Exposure limits for Radio Frequency (RF) fields are developed by international bodies such as the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The ICNIRP is a non-governmental organization formally recognised by the World Health Organisation and has drafted guidelines to protect against RF health effects. They state that: “Environmental RF levels from radars, in areas normally accessible to the general public, are normally at least 1,000 times below the limits for continuous public exposure allowed by the ICNIRP guidelines.” [3]

ICNIRP Guidelines

At frequencies in the range 300 MHz to several GHz, there is significant local, non-uniform absorption by the human body – the recommended maximum field levels are shown in Table 1 (where f is the radar frequency in MHz).

Table 1 – Reference levels for general public exposure to time-varying electric and magnetic fields (unperturbed rms values, f=radar frequency)

Also, a number of factors significantly alter human exposure to RF generated by radar systems, often by a factor of at least 100:

• Radar systems send electromagnetic waves in pulses and not continuously. This makes the peak pulse power emitted much higher than the measured average or root mean square (rms) power.
  
• Radars are directional and the RF energy they generate is contained in narrow beams. RF levels away from the main beam fall off rapidly. In most cases, these levels are thousands of times lower than in the main beam.
  
• Early warning radars are continuously changing the direction of the beam.

Challenging the standard

Some investigation into the accepted international standards is required in order to put these results into some kind of context. A recent report on the Physiological and Environmental Effects of Non-ionising Electromagnetic Radiation for the European Parliament [4] states:

“What distinguishes technologically produced electromagnetic fields from (the majority of) those of natural origin is their much higher degree of coherence. This means that their frequencies are particularly well-defined, a feature that facilitates the discernment of such fields by living organisms, including ourselves. This greatly increases their biological potency, and ‘opens the door’ to the possibility of frequency-specific, non-thermal influences of various kinds, against which existing Safety Guidelines – such as those issued by the International Commission for Non-ionising Radiation Protection (ICNIRP) - afford no protection. For these Guidelines are based solely on consideration of the ability of radio frequency (RF) and microwave radiation to heat tissue, and of extremely low frequency (ELF) magnetic fields to induce circulating electric currents in the interior of the body, both of which are known to be deleterious to health, if excessive.”

The report points out that the frequency-specific sensitivity of living organisms to ultra-low intensity microwave radiation was discovered over 30 years ago in Russia and there the exposure guidelines are approximately 100 times more stringent that those of ICNIRP. It also notes that some symptoms have been reported in epidemiological studies involving humans, animals and plant life connected with a radar operating at 154-162MHz, with a pulse repetition frequency of 24.4Hz - at a location where the intensity of the emitted radiation is comparable to that typically found at 150m from a base-station. Additional effects include [5] :

• Depressed nocturnal melatonin levels in cattle [6] .
  
• Less developed memory and attention span (as well as decreased endurance of their neuromuscular apparatus) of children living within a 20 km radius of the radar, subject to a maximum exposure of 0.00039 W m^-2.
  
• A six-fold increase in chromosome damage in cows exposed to a likely maximum intensity of 0.001 W m^-2. 

(The cited field intensities are estimated from information on the electric field intensity as a function of distance from the radar installation [7] ).

The Fylingdales radar operates by emitting a series of pulses and additional, perhaps more serious, problems may arise at frequencies around 17 Hz. As mentioned in the STOA report, this lies in the range of beta brain-wave activity and is close the frequency of a flashing visible light that can provoke seizures in people with photosensitive epilepsy. It is also the modulation frequency at which “there is a maximum in the expression of calcium ions from brain cells when they are irradiated with amplitude modulated, low intensity RF radiation over a wide range of carrier frequencies” and “any interference … could well undermine the integrity of the whole nervous system, although the extent to which this actually occurs is, at present uncertain, owing to a lack of the necessary research.”  The pulse repetition frequency of the radar is thought to be 27 pulses per second (at least, this was the documented frequency of the previous system [8] ) and it is not known whether there are any similar effects at or around this frequency that need to be examined closely.

The NMD Role

For NMD detection and warning are not enough. Accurate tracking and discrimination between warheads, debris and decoys is required. A "preliminary" architecture published in May 1999 [9] (see Table 2) describes the NMD system as being deployed in two stages. The first stage is to upgrade the current early warning radars – including that at Fylingdales. The second stage includes the installation of an additional radar system – the X-band Radar - at various sites including that of Fylingdales.

We will look at the consequences of each of these configurations in turn.

Upgraded Early Warning Radar

Table 2 shows that both NMD configurations involve the US early-warning radars in California, Massachusetts and Alaska and at Thule and Fylingdales. Currently these systems are not able to track targets accurately enough to guide interceptors. The initial configuration involves an Upgraded Early Warning Radar (UEWR) program to give them this capability. This replaces existing computers, graphic displays, communication equipment, and the radar receiver/exciter for NMD. New EWR software would allow the acquisition, tracking, and classification of small objects near the horizon and this data would be passed to other NMD elements using improved communications systems. [10]

The UEWRs would be able to search for different types of missiles, distinguish hostile objects such as warheads from other objects, and provide data to other NMD elements using improved communications systems.

The US Ballistic Missile Defense Organisation (BMDO) state that the radiated peak and average power, radar antenna patterns, and operating bands of the UEWRs, is to remain unchanged from current operations.

Table 2 – Preliminary NMD Architecture

X-band Radar

The UEWRs will still be extremely limited in their ability to discriminate real warheads from decoys or to deal with other types of countermeasures [11] . The final configuration of NMD therefore includes the deployment of new high resolution phased-array X-band radars (XBRs) which use high frequencies (5.2-8.5 GHz) and advanced radar signal processing technology to improve target resolution. These systems emit a series of electromagnetic pulses over a 50^o field of view in azimuth and elevation, and can be rotated to track targets from any direction.

The initial NMD configuration includes an XBR at Shemya in the Aleutian Islands (to cover missile launches from North Korea). The final NMD configuration would include additional XBRs at the current BMEWS sites (including Fylingdales). When fully operational each system will include a radar mounted on pedestal and associated control and maintenance facility, and a power generation facility. It will need approximately 30 to 60 personnel to operate and will encompass an area of approximately 7 hectares (17.46 acres) for the radar alone and would need to be surrounded by a 150 m (500-foot) controlled area (see below). [12]

XBRs have an average power of 170 kW and an antenna area of 123 m², which means a power-aperture product of about 20 million, but they usually incorporate a "thinned" array of only 1/5 of the total possible number of aerial elements (around 81,000) decreases the gain by a factor of 5.  In this case more energy goes into radar beam side lobes but does produce a narrower beam and provides greater tracking accuracy.

As mentioned before, these radars are intended for tracking and discrimination. Surveillance would be carried out by the UEWRs which will locate targets within a single XBR beam width - allowing detection and tracking at long ranges (2,000 - 4,000 km) despite the limited power-aperture. The detailed signature analysis for the discrimination of decoys requires a higher signal/noise ratio than that required for tracking and the range at which discrimination is possible would be significantly less than the maximum detection and tracking range

Recently questions have been raised regarding the possible danger to the health of people living close to these installations. The BMDO insists that the microwave leakage from these high power radars is safe – but independent investigations into possible health hazards need to be made.

Potential effects

Health: The XBR BMDO fact sheet [12] states that “The exposure limits established by [the US standard] ANSI/IEEE C95.1 1999 are used to ensure that public health will not be impacted by EMR emitted from the XBR”.

Two major exposure environments are defined: inside and outside a controlled area of radius 150m. Security personnel would control the area to prevent any unauthorized access. It is claimed that outside the controlled area the EMR will be no higher than the power density levels specified in ANSI/IEEE C95.1 1999. The BMDO provide the following table:

Table 3 – Comparison of EMR exposures (from BMDO [12] )

and state that: 

“There is a possibility that EMR may effect television reception out to a distance of 4 kilometers (about 2.5 miles) from the XBR and that occasional static may occur in some radios out to 7 kilometers (about 4.3 miles) from the XBR.”

However, the projected power density level is higher than that recommended by the ICNIRP guidelines for radars (10W m^-2 at this frequency range – Table 1).

Flight Restrictions: The BMDO claims that “the XBR does not require any restricted airspace or impose any flight restrictions. However, a radio frequency radiation area notice should be published on the appropriate aeronautical charts notifying aircraft of a 6.7 kilometer (3.6 nautical mile) radius high energy radiation area around the proposed XBR site”.

Wildlife: The BMDO also claim that wildlife will not be adversely affected. Although there is a potential for higher levels of exposure to birds flying through the main XBR beam, they claim that this exposure would only be for a short time and “time-averaged power densities would not raise body temperatures or cause adverse biological effects”. However, this claim is not in agreement with the European report cited earlier.

Concluding remarks

The use of Fylingdales for Star Wars gives rise to a number of concerns. Specifically:

• It would mean changing or abandoning the ABM Treaty – which is seen by many as the “cornerstone of strategic stability”;   
  
• It would enhance its status as a target, especially in times of war or international tension;
  
• It has associated environmental effects from electromagnetic radiation that need further investigation – a fresh EMR survey of the site is needed to update and re-examine the data collected 8 years ago – especially as the accepted international standards are being challenged; more studies are also needed on the extent and effects due to the low frequencies around the pulse repetition rate (27 Hz) as these may be particularly harmful to biological organisms;
  
• The introduction of the proposed X-band radar could mean an unacceptable increase in EMR levels taking them above those that recent reports indicate as desirable. Such a system could therefore result in an increased danger to local inhabitants and wildlife.

Much more research is required into the extent of EMR pollution at Fylingdales, the effects of these EM fields at the frequencies encountered and a much more in depth study of the health effects of the proposed X-band radar system.

[1] “The Unsinkable Aircraft Carrier” by Duncan Campbell, pub Michael Joseph, London 1984.

[2] “RAF Fylingdales EMR survey: second phase” by Tim Williams, Elmac Services, August 2, 1993.

[3] WHO Fact Sheet N°226, June 1999.

[4] “The Physiological and Environmental Effects of Non-ionising Electromagnetic Radiation”, by G.J. Hyland, Private Treaty No. EP/IV/A/STOA/2000/07/03.

[5] Science of the Total Environment; Issue No 180, 1996.

[6] “Study of Health Effects of Short-wave Transmitter Station at Schwarzenburg”, by E.S. Altpeter et al., University of Berne, Inst. for Social & Preventative Medicine, August, 1995.

[7] “Measurement of the intensity of electromagnetic radiation from the Skrunda radio location station, Latvia”, by T. Kalnins et al, Science of the Total Environment 1996, 180:51-56

[8] Jane’s Radar and Electronic Warfare Systems, Second Edition, page 62, 1990-1.

[9] “Inside Missile Defense”, by M. C. Sirak 19 May 1999, p13.
See also The Ballistic Missile Defense Organization web-site - www.acq.osd.mil/bmdo/bmdolink/html and “NMD Program Fact Sheet” from BMDO - www.acq.osd.mil/bmdo/bmdolink/pdf/jn9905.pdf

[10] “Early Warning System Fact Sheet” from BMDO - www.acq.osd.mil/bmdo/bmdolink/pdf/jn0013.pdf

[11] See: “Countermeasures” - a report on NMD from The Union of Concerned Scientists at MIT - in pdf format (4.98 Mb) – www.ucsusa.org/arms/CM_exec.html and
“Why National Missile Defence Won’t Work”, by G.N. Lewis, T.A. Postol, and J. Pike, Scientific American, August 1999, pp 36-41 – www.globenet.free-online.co.uk/articles/nmd.htm

[12] “X band radar Fact Sheet” from the BMDO - www.acq.osd.mil/bmdo/bmdolink/pdf/jn0019.pdf