This paper gives the Air Ministry's view on the underground launchers or silos for Blue Streak. Much criticism has been made of Blue Streak as being slow to launch, impossible to fire within the so-called "four minute warning" the UK was supposed to have before a Soviet attack.

This criticism is meaningless for several reasons.

Here is the requirement:




1. To be an effective deterrent, our ballistic missile system must have a high survival probability on the ground and in the air against an unexpected attack. It must be capable of retaliating, in the shortest possible reaction time, under any weather or radio-active fall-out conditions.

2. The Air Staff require the ballistic missile system to be maintained at a high state of readiness for long periods and to be housed and protected in an underground firing site.


3. The Air Staff require a secure underground firing site as an integral part of the ballistic missile system.



4. It is intended to deploy 5-10 underground launching sites around a central domestic and technical facility.

5. The form of the deployment of the sites will be such that no more than one site can be destroyed by a 20 megaton yield weapon either air-burst or ground-burst.

6. Each site must be self-supporting, in an emergency prior to an expected attack, for a minimum of three days, including a limited capability to repair the system by replacement.

Protection Against Attack

7. The Air Staff would prefer the missile to be launched directly from underground, but in the development for this is likely to delay the in-Service date they would be prepared to consider an alternative method of launching in which the missile is raised to the surface before firing. Such a launching arrangement must not adversely affect to a significant degree, the vulnerability of the system and the firing crew, the accuracy of the missile or the reliability of the overall system.

8. It is most desirable that the degree of protection afforded by the underground site against a 1 megaton yield warhead exploding on the ground or in the air at a half a nautical mile from the site without warning should be sufficient to permit the missile to be successfully fired after such an attack without requiring rectification effort from outside sources. The aim should be to keep the time taken to rectify and launch the missile to within six hours, but the operational usefulness of missiles which can be launched within 24 hours of an attack is considered sufficient to justify the provision of the necessary rectification facilities. The Air Staff wish to be informed of any particular circumstances which might prevent this design requirement being met economically.

Multiple Launchers

9. The Air Ministry has made a study of the implications of reliability and economies on the problem of achieving the maximum launch probability of a warhead Although a single missile may be acceptable the study indicates that the optimum deployment may be two vehicles/launchers per warhead with provision for moving the warhead from one launcher to the other; the site must therefore be designed to meet either of these contingencies. A decision on single or twin deployment will be made before construction of operational sites is commenced in the United Kingdom. As missile handling, preparation and test equipment may not be any more reliable than the missile it follows that, in the twin site, it may also be necessary to duplicate this support equipment, and this must be catered for in the design study. If twin site deployment is decided upon in due course it may be possible to provide a warhead for each vehicle and hence it may be necessary to operate such installations as " double barrel systems " .

Operational Readiness

10. The requirement for the state of readiness and standby condition is being studied by the Air Ministry. Further information on this subject will be promulgated in due course.

All-Weather Capability

11. It must be possible to prepare and fire a missile under all weather conditions likely to be experienced in the United Kingdom, using only the facilities and resources within the underground launching site. If a lift system is proposed, the Air Staff would expect to be advised of the nature and extent of the restrictions on launching.

Safety Precautions

12. The launching party is to be given complete protection, at their firing stations, against normal launch effects such as the exhaust blast of the missile. In addition, all reasonable measures consistent with the operational effectiveness of the site, are to be taken to protect the launching party against the effects of a fuel explosion of a fully fuelled missile.

13. In its stored position, the warhead must be protected by fire-proof bulkheads, or other effective means, against damage by fire and nuclear hazards. It is highly desirable that launch crews be protected against an H.E. explosion of the warhead and attendant radiation hazards; it is obligatory, however, that any radioactive contamination be restricted to the immediate vicinity of the launcher complex.

14. Provision is to be made to extinguish or limit outbreaks of fire anywhere on the site.

15. The site must be so positioned that no other building or installation in the vicinity can be damaged by blast or fire resulting from the explosion of a fully fuelled vehicle. Fire breaks must also be provided.

16. The question of the local security of the site will be the subject of further investigation by the Air Ministry, who will examine and decide upon the extent and depth of the security measures to be imposed, the size of the security area required, and the need for camouflage.


Design flexibility

17. It is desirable that the design of the underground launching sites should be capable of accepting future generations of ballistic missiles, if this is possible.

Access facilities to and Within the Site

18. The mode of transportation of the missile from the factory to the site is at present under investigation. Access to the site by the missile transporter loaded with the empty missile and all other equipment required at the launching site, is to be provided. Access roads are to be provided to surface installations requiring frequent servicing, and an area of hardstanding in the vicinity of the firing shaft is required for the missile transporter to manoeuvre the missile into a position from which it may be lowered into the firing shaft.

Automatic Operation

19. With the object of reducing~manpower requirements to a minimum, it is required that the operation of power generating sets, fuelling, preparation and testing procedures, should be as automatic as possible; the ultimate objective is complete automation of these processes.

Electrical Power Supply

20. Wherever possible, power for peacetime operating must be taken from the national grid network. Sufficient generating capability is to be provided within the underground firing sites for the independent operation of all services and test equipment required to launch and maintain the missile for a minimum of three days in the event of a failure in the national grid system. In addition, generators are required to operate for 2 hours after an attack to meet the requirements detailed in para.8 above.


21. It must be possible to carry out all relevant servicing operations on components on the vehicle, including the warhead and support equipment, in their normal positions in the underground site: the normal position for the warhead will be in the warhead store.

22. The design of the site is to take into account the requirement to obtain a high level of serviceability and a high probability of completing check-outs and firing count-downs. Environmental control of the missile and the servicing bays is to be used to achieve this where appropriate.

23. All the necessary handling, assembly, fuelling, testing and servicing equipment is to be developed as required by O.R.1139 and O.R.1142, or maintaining the missile and the support equipment in such underground launching sites.

24. Servicing policies will be issued separately by D.Eng.G.W.


25. Tankage for the long-term storage of liquid oxygen and kerosene to enable the missile to be fuelled plus adequate reserve for exercising the system is required on each launcher installation. Two way transfer facilities are required. The storage tanks must be located to minimise the risk of fire from explosions due to inadvertent mixing of liquid oxygen and kerosene, or of liquid oxygen or kerosene with any other incompatible material.

26. The most suitable method for generating and supplying liquid oxygen to the static tanks is being studied by Air Ministry. Kerosene will be replenished periodically from a central depot.

27. If the requirement for periodic check-out of the complete pressurisation system on the site is confirmed, consideration should be given to any method which will enable this to be carried out without igniting the main combustion chambers. In the interests of safety, it must be established that this can be carried out with short duration runs involving less than 100% of the fuel and oxidant normally contained in the weapon. The Air Staff wish to be informed if the use of inert liquids for training purposes would be likely to have an adverse effect on missile reliability, No practice refuelling operations or short duration component runs will be carried out unless the warhead is removed from the vicinity of the site.

Testing and Check Out

28. The underground site must include provision for the necessary instrumentation and test equipment to allow for the accurate setting-up of the missile and for servicing.

29. If the requirement for changing the target bearing involves traversing the missile on its launcher, this must not prejudice testing or check-out procedures.

Storage Facilities

30. Storage facilities are required at the underground site for spare missile assemblies and parts of ground support equipment required for repair by replacement under the conditions stated in paragraph 6 above. This requirement is additional to facilities required at the central installation for which a separate technical requirement will be issued by DEng.G.W.

Domestic Accommodation

31. Provision is to be made within the underground launching site for domestic accommodation for personnel required to launch the missile. Such accommodation is to be suitable for occupation in the conditions referred to in para.6 prior to an expected attack, for a period of not less than three days, and should include simple cooking facilities and provision for the storage of emergency rations. At all times, the launching crew must be safeguarded against the effects of an attack for at least 24 hours to an extent which would ensure that the requirement specified in paragraph 8 above can be met.


32. The underground launching site is to be proved and demonstrated for Service use so that operational sites may be constructed in time to receive Blue Streak coming into service.

33. Any factors which might accelerate or retard introduction of the underground launching sites is to be brought to the attention of the Air Ministry without delay.

Air Ministry (D.O.R.(C.))

29 August 1958

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