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Aviation History
1960
1960 - 1246.PDF
184 .••;.-. :;*. .••"-..-• • ;'[/ SPACE SPECIAL FLIGHT, 5 August BRITAIN'S BOOSTER -**••• LAST week's statement (page 182) by Mr Sandys made it clearthat it will be some little time before the GovernmentJ feels able to issue a public statement on Britain's future in • the space age. One thing, however, is quite obvious: if we do decide to "have an adventure in space," it is sure to be on the back of Blue Streak. This long-range ballistic missile was first announced by the Minister of Defence in August 1957. Its cancellation as a military weapon was announced last April—for reasons which need no repetition here. To a considerable degree the design of Blue Streak has benefited by experience with the Atlas ICBM, and with the blessing of the US Defense Department much classified knowledge has been passed by Convair, Rocketdyne and other companies to the team charged with the development of the British weapon. (We might add that there has been a corresponding reciprocal flow to America.) The latter is led by de Havilland Propellers Ltd, who are responsible for management, assembly and test, and includes de Havilland Aircraft for the airframe, Rolls-Royce for propulsion and Sperry for guidance. Structurally the airframe is a logical extension of the stainless-steel "balloon" monocoque developed for Atlas, although rather more of the British vehicle is stabilized by axial corruguations. Propulsion is effected by twin gimballed chambers, each probably rated at some 150,0001b at sea level on liquid oxygen and kerosine and flanked by a prominent stackpipe from its associated turbopump. Design range of this basic vehicle has always been assumed to be of the order of 3,000 miles, carrying a typical thermonuclear payload weighing several thousand pounds. Used in conjunction with suitable upper stages, Blue Streak is obviously a booster of . considerable capacity, and one which might show singular advantages over most other militarily-derived vehicles in the West. Not only have D.H. Propellers made various proposals for second and third stages, but the RAE have for many months been engaged in detail design studies. Most of these investigations are predicated on the assumption that the second stage would either be Black Knight or a modification of this exceptionally reliable vehicle. Mating Blue Streak and Black Knight could be done for a very modest sum. The detail design has been virtually completed, and very little need be done to make such a marriage a fait accompli. The resulting vehicle would be able to place a payload of about 1,0001b in a 300-nautical mile Earth orbit, sufficient for a wide variety of missions. However, the existing Black Knight is far from being the optimum second stage. Its high fineness-ratio would impose structural penalties near the junction with the booster, and might make the vehicle unwieldy on the launcher (in high winds for example). Moreover, the Blue Streak and the unmodified Black Knight are not perfectly compatible in performance. As was first outlined in our issue of September 11, 1959, de Havilland Propellers have prepared a design for an optimized two-stage combination, in which the second stage consists of a modified Bristol Siddeley Gamma engine fed with propellants housed within a spheroidal tank which, although much shorter than that of the original Black Knight, would have greater capacity. The HTP and kerosine would be separated by a cylindrical diaphragm which makes for a very efficient structure. As the accompanying drawing indicates, small HTP nozzles would be incorporated to provide attitude control and assist in the regenera- tion of the propellants after coasting at zero g. Although the powerplants are essentially unchanged, this repackaged second stage matches the first stage so closely that the resulting combination would have approximately double the Manager of the Project Office at de Havilland Propellers Ltd con- cerned with spacecraft based on Blue Streak is G. K. C. Pardoe, seen here with models of the original ballistic missile and of a suggested second stage based on Black Knight performance of the unmodified scheme. Calculations show that it should be able to place a payload of the order of 2,0001b in a 300-n.m. Earth orbit, and proportionately smaller or greater payloads along other trajectories. Thus, the Blue Streak and modified Black Knight fomi a combination with an overall capability greater than that of the Sputnik 1 vehicle and all the American first-generation launchers. It is not, however, able to match the performance of Atlas-Agena, Centaur or the Soviet multi-stage rocket which launched Sputnik 4; Britain has so far announced no plans for the develop- ment of more-advanced boosters and has no experience at all of large engines running on liquid hydrogen. Nevertheless the two vehicles illustrated opposite could perform nearly all the military, scientific and commercial missions which currently seem to be of interest, and it is possible to cast a brief look at some of the things that might be attempted. Scientific From what one can gather, the former Minister of Aviation, Mr Duncan Sandys, has devoted most of his spaceflight energies towards the fulfilment of purely scientific requirements. The possibilities are limitless. Even the Astronomer Royal—no lover of science fiction—has spoken with some enthusiasm of the improved photographs of the Universe which could be obtained with the aid of a telescope stationed above the Earth's atmosphere. Most of us are so used to living on the Earth's surface that we tend to forget the potency of the atmosphere as a filtering medium; and, although it forms a blanket without which we should die, it cuts off a vast range of electromagnetic wavelengths and introduces distortions and aberrations which are difficult to measure. The British two-stage vehicle could undoubtedly carry a telescope, photographic system and print transmitter which could enable "true" pictures to be obtained. At the same time, the efficacy of the atmosphere as a blanket has made astronomers long wish for a space-located observatory which could investigate infra-red and ultra-violet "sources" with the same accuracy that radio astronomy can now be conducted from the Earth. At present astronomers do not even know exactly what they are missing, since the absorption spectrum of the atmosphere has not been precisely determined, and in any case it is impossible to infer the existence of something from its absence. Other investigations which teams in Britain are already discussing involve geomagnetism, cosmic rays, the Van Allen belts and simple plots of density, temperature and other basic parameters. Commercial The possibility that adventures in space might yield lucrative returns is undoubtedly a significant factor in deciding whether Britain should "have a go" or not. He would be a bold prophet who would risk all his capital in so uncertain a field, but in many areas it can be shown on paper that likely returns exceed the likely expenditure. In the field of communications, for example, the Postmaster- General has already been drawn into discussing the relative merits of submarine cable systems and communications satellites. The latter need to be thrown into a very high, ellipitic orbit, ane. although the required trajectory would cut the payload to much less than 2,0001b, the available weight would still be ample for a useful orbiting vehicle. Launch times and dates would need to be so chosen as to ensure that any such satellite spent the maximum part of its life in sunlight, since solar cells would doubtless be used to provide the internal power necessary. A series of six satellites would provide global voice communications over a large number of channels, and it would be strange indeed if the British electronics industry was not able to achieve an adequate signal:noise ratio and reliable performance within the limitations of size and weight imposed. Owing to the Earth's oblateness, the plane of a satellite's orbit routes, and the orbit also rotates within this plane (the apogee/ perigee diameter precesses). For a communications satellite it is desirable that these variations should be minimized, and it is possible to eliminate them without propulsion in orbit by carefully launching into an orbit which makes an angle of about 63° with the plane of the Equator. A similar orbit would probably be chosen for a navigation satellite. This would, in effect, merely provide another heavenly body upon which mariners (and possibly aircrew) could practice astro- navigation. It could be a purely passive (i.e., not transmitting) object, and should ideally be placed in a low orbit—300 n.rn- would give an adequate life. One such satellite would give a position line, and two a running fix. There would be no paylosa limitation, and the space above the modified Black Knight would
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