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Aviation History
1963
1963 - 2177.PDF
978 FLIGHT International, 12 December 1963 Missiles and Spaceflight TABLE 4 range of 1,000km all lie within 0.25 of their average, +6.77. The difference in magnitude between these Cosmos spacecraft and the standard one-metre US sphere (+7.84) is thus +1.07. If we also assume that American and Soviet satellites reflect approximately the same percentage of sunlight, then the ratio of the two diameters is given by +1.07 = 2.5 log10 (djd^y from which we find djda equals 1.64. It is probable, therefore, that the above Cosmos satellites, if spherical in shape, must have a diameter of about 1.64m, with a possible error of ±0.2m. Density of the satellites To find the weight of these objects, we must first examine the density of Russian satellites generally. The Soviet Union has released both the size and weight of only a few spacecraft, and these are compared with four US satellite types in Table 3. The densities vary widely, early satellites such as Sputnik 1, Lunik 1 and 2 apparently carrying the "dead weight" of heavy medallions and chemical batteries rather than delicate instruments. By comparison, the Lunik 1 rocket and the recent Vostoks had densities of only 0.4 and 0.7 grams per cubic centimetre and, if pressurized, would have floated in water. To derive a reasonable density for the Cosmos spacecraft, we will use Sputnik 3, Lunik 3, the Venus and Mars probe, all of which were well-instrumented scientific satellites. The average density is 342kg/cu m, and a sphere of 1.64m (±0.2m) diameter would therefore weigh 785kg (± 300kg). It must be remembered, however, that in extreme cases the density might be as low as 60kg/cu m or as high as l,000kg/cu m. At the lowest value, the satellite's weight would be only 140kg (±50kg), making them the lightest Soviet spacecraft ever launched (excepting Sputnik 1). Although this would compare reasonably with many US payloads, it is probably too small for a Russian one, especially as the final-stage rocket bodies for the Cosmos series appear no smaller than those used for satellites weighing thousands of kilograms. At the highest density, the weight proves to be 2,300kg (± 900kg), which is about the mass of the Sputnik 4 cabin, which carried a "mechanical man" as a prelude to the Soviet biological satellites. This estimate is probably too high, since the highest scientific payload launched, excluding the dog-carrying capsules, was Luna 4 weighing 1,400kg. Absolute magnitude (s - 1.000km) Diameter of sphere (Im - +7.84 mas) Weight of sphere (342 kg/cu m) Weight of sphere (A/W = 0.0047) Minimum weight (60 kg/cu m) Maximum weight (1,000 kg/cu m) Minimum +6.52 l.4lm (4.1ft) 500kg (1.1001b) 330kg (7251b) 90kg (1901b) 1,455kg (3.2101b) Average + 6.77 1.64m (5.37ft) 785kg (1,7351b) 450kg (9901b) 140kg (3051b) 2,300kg (5,0651b) Maximum +7.10 1.84m (6.02ft) 1,110kg (2,4451b) 565kg (1.2401b) 195kg (4301b) 3.240kg (7,1401b) Probable weight = 600kg (±200kg) Probable diameter 1.6m (±0.2m) There is another way of resolving the uncertainty in the weight estimate—by observing how quickly the satellite decays. The rate at which a satellite's orbital period changes increases with the atmospheric density at perigee height and with the average cross- sectional area (A) which the satellite presents to the air. This air drag becomes less effective the greater the satellite's weight (W). Since the atmospheric density and the orbital elements are known we can find the value of A/W, and for Cosmos 2 and 5 this works out as 0.0047 sq m/kg. The particular sized spheres we have deduced have a cross-sectional area of about 1 sq m, and their weight becomes 450kg (± 120kg). If the atmospheric density is not sufficiently well known, the value of A/W could be found by comparing the lifetimes or rate of decrease of orbital period of a Cosmos with those of a known satellite in a very similar orbit. All these results are summarized in Table 4. We may conclude that the satellites in the 49° Cosmos series most resemble Lunik 3 or the Venus probe in general dimensions and weight, although they are probably less irregular in shape. While they exceed the largest spherical US satellite—Courier IB, which is 1.3m in diameter—they are smaller than the American Agena and AbleStar second stage rockets measuring 6m long and l£m across. It is also likely that they are small and light enough to be launched by the same booster used to orbit Sputnik 3. If we assume that none of the Soviet launch vehicle configurations were termin ated by a bulbous nose, the Sputnik 3 rocket must have had a minimum diameter of 1,73m—enough to encase a Cosmos sphere— and was powerful enough to loft a 1,300kg payload to an average height of 1,040km. In fact these Cosmos satellites may be nothing much new at all. . . . RCA at Merritt Island The US National Aeronautics and Space Administration is negotiating with RCA Service Company a contract to operate and maintain a technical communication system within NASA's Merritt Island launch area north of Cape Kennedy. Value of the contract is expected to exceed $4m over a three-year period. Kennedy Space Centre In an executive order dated November 29, President Lyndon B. Johnson designated "the facilities of the Launch Operations Center of the National Aeronautics and Space Administration and the facilities of Station Number One of the Atlantic Missile Range, in the State of Florida" as the John F. Kennedy Space Center. With the co-operation of the Governor of the State of Florida, also, the President announced his intention of renaming Cape Canaveral, where the centre is located, as Cape Kennedy. Six Men, One Saturn NASA has selected Douglas Aircraft Co for negotiations leading to "a follow-on study contract for refine ment and evaluation of a NASA manned orbital laboratory concept," following three-month studies by this company and by Boeing. Both NASA and the Department of Defense are interested in possible requirements for a manned orbital research laboratory and indeed have mutually agreed on the scope of the Douglas study contract. According to NASA, "The Douglas study will consist of refining the NASA concept of an orbiting laboratory which assumes a cylindrical six-man spacecraft capable of being launched by the Saturn rocket. The study will examine the feasibility of using equipment to provide intermittent artificial gravity for the spacecraft crew. Douglas also will examine the feasibility^ot launching both ferry and supply spacecraft on a single vehicle. Soviet ICBM Claim Writing in the Soviet Government newspaper Izvestia, Marshal Nikolai Krylov, Commander of the Soviet Rocket Troops, claims that Soviet rockets can "change their course,' are "invulnerable to anti-missile missiles" and can arrive on target witn extreme accuracy. South African Missiles The Republic of South Africa has "been forced by events in Africa to enter the missile field." As ior^c in our September 12 issue, work is going ahead in the field ° guided weapons, and the aforementioned statement was ma recently by Prof L. J. Le Roux, vice-president of the Council to Scientific and Industrial Research in Johannesburg. Prof Le R° went on to state that a Rocket Research Institute is to be establisn near Pretoria, and that its first major assignment will be the "eve'°^ ment of a surface-to-air weapon. He went on, "The new insti will give the Republic a foothold in space and weather researc Defence research, which began little more than a year ago- already achieved some striking successes and has saved the couo,) hundreds of thousands of Rand in the knowhow and e1uip?)lis which would otherwise have been bought overseas at tremenoo cost."
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