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Aviation History
1960
1960 - 0619.PDF
Missiles and Spaceflight . . . SPACE VEHICLES DISCUSSED A varied selection of papers was presented at a conference on thestructural design of space vehicles organized by the American Rocket Society in Santa Barbara, California, last month. Theseincluded the three papers, summarized below, presented by repre- sentatives of the Rand Corporation, Douglas and Chance Vought.Much had already been said and written about the problems of getting to the planet Mars, but it remained for Francis T.Cartaino (Rand) in his treatise Vehicles for the Exploration of Mars to discuss what one did after arrival there. Early martian explora-tions would undoubtedly be conducted on foot, but it would ultimately be desirable to move about by mechanical means.A family of Mars exploratory vehicles included the following types: ambulatory, surface, helicopter and aeroplane. The essential feature of the ambulatory system was a pressuresuit, similar in appearance to present-day g-suits. The martian suit would have to be worn for continuous periods of several days,however, and accordingly would need to furnish a breathable atmosphere, ventilation, temperature regulation, feeding andelimination and to afford complete reliability. The projected surface vehicle consisted of a tubular chassis, wheel assembly(with brakes and low-pressure tyres), rocket turbine drive, fuel tanks, and a crew and equipment cab. Design of the helicopter and fixed-wing aircraft hinged on thenature of the martian atmosphere, which was assumed to be composed of 96 per cent nitrogen, 3.7 per cent argon and 0.3 percent carbon dioxide. Because there was no oxygen, all propulsion systems must be of the non-air-breathing kind. Atmosphericdensity of the martian atmosphere was guessed to be quite similar to that of the Earth at about 55,OOOft altitudes. Other aerodynamicparameters such as Reynolds number and acoustic velocity also did not differ significantly from familiar quantities, and it washence reasonable to postulate the design of aerodynamically (if "aero" is the proper prefix) supported vehicles. Rocket turbinepower was forecast for the helicopter and aircraft alike. The former vehicle required low disc-loading and was of the inflatabletype (as was the aircraft). A conventional high-wing configuration was suggested for the aircraft, which was to have twin enginesdriving propellers (or "rocket props"). Wing loading was of the order of 151b/sq ft, which allowed take-off and landing runs lessthan 1,000ft. Design cruise speed was 180kt. Four Douglas Aircraft Company representatives presented apaper, entitled Entry Vehicles for Mars and Venus, which dis- cussed thermostructural design problems to be encountered indesigning planetary probes. The martian atmosphere at upper altitudes was more dense than that of the Earth, and the massof the atmosphere was more uniformly distributed between high and low altitudes (see first table). Consequently, the cqnvectiveheat transfer (due to skin friction) became significant at just over one million feet altitude and was relatively uniform during descent. PLANETARY ATMOSPHERE DATA (DOUGLAS) Principal components of atmosphere:— Nitrogen Oxygen Carbon dioxide Thickness of effective atmosphere (ftxim) Surface pressure (Ib/sq ft) Surface density (Ib/cu ft) Average temperature of atmosphere (°F) Acceleration of gravity at surface (ft/sec2) Escape velocity at surface (ft/sec) Earth 79% 20% trace 1.0 2,116 0.0765 —9 32.17 36,677 Mars QCO'70 /O trace 1.2 136 0.0063—70 12.9516.825 Venus 10% trace 90% 0.8 19,640 1.00 80 28.30 33,697 Surface atmospheric pressure on Mars was one-twelfth that ofEarth and, with a lower pressure gradient than that of Earth, deceleration of a descending vehicle was more gradual and theheat transfer less severe. In conclusion, the authors stated that the design of Mars and Venus probes would prove quite interestingand a rewarding task for the future. Not only was the task feasible FLIGHT, 6 May 1960 619 Negotiations began last month between NASA and the Tapco Group of Thompson Ramo V/ooldridge for the development of this solar auxiliary power system for spacecraft. The 32ft parabolic petal-type solar collector is shown folded (right) to fit in the nose fairing of a launch vehicle such as Centaur or Saturn. The device, which is designated Sunflower 7, should weigh some 7001b and generate 2kW for approximately one year and economical, but it could be accomplished with existingmaterials such as aluminium or phenolic nylon. Two Chance Vought engineers (Bilodeau and While) presenteda treatize on the Structural Design of a Manned Satellite Labora- tory. A three-man, non-recoverable 14-day scientific laboratorywas envisaged which would have a separate re-entry vehicle. The design and construction of such vehicles was quite feasible, andwould initially be used for qualification of life-support systems. Ultimately, however, they would be employed for other scientificand perhaps military purposes. A 16ft long chamber was proposed, with 81 in outside diameter.The laboratory would weigh 5,0001b (see second table), which limited booster selection to Saturn-class systems, and was to beorbited at a 300 n.m. altitude. Conventional aluminium sandwich construction appeared to be the best compromise from strength-to-weight considerations at elevated temperatures. The proposed laboratory had a good growth-potential and could be developedinto a system wherein six individual modules were mated together in ring form to establish a large permanent space station. WEIGHT BREAKDOWN (CHANCE VOUGHT) Diameter (in) Length overall (ft) Weight breakdown (Ib):— Shell Internal support structure (shelves, seats,consoles, brackets, etc.) Systems:— Environment (2 refills) ... Food and provisions Controls ... Instrumentation ... Displays and instruments Guidance and navigation Communications Electrical power supply (batteries, solar cells) Furnishing and miscellaneous ... Payload Total weight (Ib) Structural weight ratio (per cwt) Three-man,14-Day Design Design based on based on loads hazards 81 16 715 375 770 85 740 200 80 2560 1,100260 550 4,960 22.0 81 16 960 375 770 85 740 200 80 2560 1,100 260 550 5,20525.7 Three- Man 30-Day Growth version 105 16.3 930 500 1,310 190 970 204 150 100 330 2,500 370 3,090 10,644 13.4 At the conclusion of their presentation the Vought engineersemphasized that much basic environmental data were required before any design could be "finalized." Other speakers and manyin the audience echoed this view, and it was apparent that although environmental-type satellites received less publicity than some ofthe more spectacular space flights, they nevertheless constituted a vitally important part of any space programme. A Boeing K.C-135 tanker/transport aircraft is to be used for zero-gravity experiments by the Wright Air Development Division of the US Air Force. Trajectories giving a 40sec period of weightlessness willbe flown at 25,000ft. Garbled signals caused by a faulty diode in a "telebit" unit of theUS artificial planetoid Pioneer 5 were overcome last month by devising a new translation code for the signals. At this time Pioneer 5 was5.5 million miles from Earth and its signals were still being received by both Jodrell Bank and South Point, Hawaii. A Martin Pershing selective-range ballistic missile for the US Armywas successfully launched from Cape Canaveral on April 20. This was the second Pershing firing. The first stage burned for 50sec, sendingthe dummy second-stage some 35 miles over the Atlantic. On April 22 the USAF (SAC 576th Sqn) successfully launched anAtlas from a "Hollywood-hard" coffin-type emplacement at Vandenburg AFB. A limited number of such partially hardened emplacements isprogrammed, although the majority of Atlas squadrons will be fully hardened (at Lincoln, Nebraska; Salina, Kansas; Roswell, New Mexico;Alms, Oklahoma; Abilene, Texas; and Plattsburgh, New York). The Japanese Defence Board confirmed recently the signing of acontract with the US Navy for the purchase of 42 Tartar missiles to be delivered from Convair-Ponoma before the end of 1961. They will beused aboard destroyers of the Maritime Self-Defence Force. Japan will pay half of the overall cost of some $4,455,000. In addition, the JDAwill import 24,800 Mighty Mouse spin-stabilized rockets and 60 Side- winder missiles during the current Fiscal Year for a total of $1,469,444,and has allocated $241,000 for developing Japanese air-to-air missiles.
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