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Aviation History
1961
1961 - 1338.PDF
442 FLIGHT, 14 September 1961 TRIPARTITE CONFERENCE Delegates from the US, Canada and the UK Meet at the Royal Aeronautical Society OVER 500 delegates from three aeronautical learned societieshave been attending the 1961 conference at the RoyalAeronautical Society's new lecture theatre in London this week. Participating for the first time, in common with America'sInstitute of the Aerospace Sciences and the RAeS is the Canadian Aeronautical Institute. As a preliminary to the SBAC Show, which almost all the dele-gates attended, there was a reception on September 3, and some Flight photographs taken on that occasion appear in these pages.Last Monday the four-day technical session began and summaries of the 15 papers are given below; we hope to accord more detailedtreatment to certain of these in future issues. Though not strictly a part of the conference, the 49th WilburWright Memorial Lecture also took place, being given last Tuesday by Dr Abe Silverstein, Director of Space Flight Programs in theNational Aeronautics and Space Administration. His subject was Researches in Space Flight Technology, and he showed how researchmethods evolved during over 50 years of manned flight have provided a foundation for rapid development of the new science.The lecture went on to review some of the current work on the aerodynamic propulsion, structural and environmental aspects ofmanned spaceflight. It is intended to report the paper in some detail in an early issue of Flight. Meteorological Measurements from the Tiros Satellites, by W. G. STROUD Chief, Aeronomy and Meteorology Division, ManagerGoddard Space Flight Center, NASA) Two Tiros (Television- Infra-Red Observation Satellite) satellites have yielded an enormousquantity of information on the distribution of clouds and electro- magnetic radiation over the surface of the Earth. The analysis andinterpretation of the data are still in process. However, more than 35,000 television pictures of the Earth have been scanned and,where possible, nephanalyses prepared. More than 750 orbits of Tiros II radiation data are being converted to digital tapes forcomputer use and to radiation maps for visual inspection and analysis. Both Tiros I, launched April 1, 1960, and Tiros II, launchedNovember 23, 1960, were placed in nearly circular orbits at 400 n.m. altitude with inclinations of roughly 48°. In both cases, the orbitperiod was approximately 99min. Tiros I, which contained two television camera systems, one wide angle covering roughly 750 by750 miles and a narrow angle covering roughly 70 by 70 miles, operated for 79 days, yielding 24,000 pictures, 16,000 of which wereof sufficient quality and contained enough cloud information to be used for analyses. Square clouds associated with tornado activity,mountain clouds, desert features, the glinting of the sun on the sea, in addition to the unexpectedly large-scale organization of clouds,are all seen for the first time from satellite altitude. The Tiros II was distinguished from Tiros I by the addition of aradiation-detecting system which, using the spin of the satellite to produce the scan line, mapped out the distribution of radiationin 6.3 micron (water vapour) region, the 8 to 12 micron window, the 7 to 30 thermal region, and two visual channels, 0.55 to 0.75micron for comparison with the television, and the 0.2 to 6 micron (albedo) region. These data are acquired by the satellite in anindependent data storage and telemetry system with some unique features and transmitted over an independent telemetry link. Onthe ground, the data are processed to produce digital magnetic tapes which can be handled by means of the IBM 7090 computerfrom which they can then be plotted out or printed out as desired for future analysis and study. The Tiros satellites have demonstrated the potential of this moderntool for the exploration of meteorology on a global scale. On the Attitude Control of Earth Satellites, by E. G. C. BURT (Headof Dynamic Analysis Division, Guided Weapons Department, Royal Aircraft Establishment, Farnborough) The paper discusses severalpossible methods for the attitude control of satellites, and dis- tinguishes between active, passive and semi-passive systems. Activecontrol refers to the usual concept of an error-actuated, feedback control system, where the attitude error (or some function of it) issensed explicitly, and used to control a torque-producing device. This method, of general applicability, presents no particular diffi-culty in the field of control theory; the real problems arise in the design of physical elements which must operate in a weightless,airless environment. For Earth-orientated satellites it appears possible to use passiveor semi-passive methods, making use of a particular set of reference axes in which some of the torques acting on the vehicle (e.g., that due to the gravity gradient) have a stabilizing effect. Attitude con-trol is then achieved merely by dissipating energy, and no sensing elements or feedback loops are required. Energy is removed bydamping the relative motion between two different parts of the satellite; the passive system relies on moments of inertia differencesto induce the relative motion, while in the semi-passive method this is augmented by introducing additional gyroscopic effects. The possibilities of a fluid damping system are considered,and the semi-passive method is discussed in some detail. It is shown that, by suitably modifying the dynamic response, the effectsof certain disturbing torques, such as that due to solar radiation pressure, can be greatly reduced. The passive and semi-passive methods appear to hold co nsiderablepromise, particularly for those missions where the need for relia- bility and longevity is paramount. Upper Atmosphere Experiments with Particular Reference to BlackKnight and Skylark, by PROF SIR HARRIE MASSEY (Quain Professorof Physics, University College, London) For some years now the solid-fuel-propelled rocket Skylark has been used to transportequipment to altitudes of up to 200km for the study of upper atmosphere properties. The rockets have been launched at Woomeraand the work has involved co-operation between British Universities (co-ordinated by the Royal Society), the Royal Aircraft Establish-ment and the Australian Weapons Research Establishment. An account will be given of some of the techniques used and the resultsobtained in a wide range of investigations. The value of high-alti- tude rockets, such as Black Knight, for testing equipment to beflown in satellites and for certain specific investigations will be discussed. Air Marshal Sir Owen Jones, RAeS president, and Dr H. Guyford Stever, IAS president Communications Satellites, by DR GEORGE E. MUELLER (Vice-president for Space Systems Program Management), WILLIAM B. HEBENSTREIT (Director of Advanced Projects, Program and Planningand Development) and EUGENE R. SPANGLER (Staff Assistant inSpace Systems Program Management, all of Space Technology Laboratories, Inc) The major decisions affecting the establish-ment of wideband communications systems using satellites are discussed from the point of view of the optimum use of availableand nearly available hardware and techniques to satisfy the fore- casted requirements. Choices in the design of the communicationsrelay system, in orbit selection, in temperature control, in ground- Station design, and their bearing on each other, on cost, and onreliability are reviewed, and basic criteria are established. It is concludsd that active relays in 24hr or 12hr circular orbits are likelyto be the optimum choices. Ground Proximity Effects Associated with V/STOL Aircraft, by JOHN P. CAMPBELL (Aerospace Technologist, NASA LangleyResearch Center) Various problems arising from operation of V/STOL aircraft close to the ground are discussed. All forms ofground proximity effects are covered, including effects of slipstream impingement and recirculation on the surface beneath the aircraft,on objects around the take-off and landing area, and on the aircraft itself. The characteristics of the slipstream are first discussed, andit is shown that there is a rather rapid decay of slipstream velocity following the vertical impingement of the slipstream on the surface.
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