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Aviation History
1961
1961 - 0107.PDF
FLIGHT, 27 January 1961 107 ranches. Jodrell Bank and Slough are also on this circuit.In connection with the joint Anglo-American satellite to be •lunched late this year, and possibly with other satellites, thew'inkfield station will record and retain telemetred data for the iirect use of British scientists as well as passing it on to Goddard.T he normal procedure for new data received from the first joint -atellite and conveyed to Goddard will be for the NASA centre c reduce the data and then send it back to Britain for interpreta- ion of the scientific results.As a unit of the Radio Research Station, the Winkfield facility omes under the control of the RRS director, Mr J. A. Ratcliffe,PRS, and division head Dr H. G. Hopkins. The RRS satellite -nd space group is led by Dr B. G. Pressey, and the stationnanager at Winkfield is Mr Charles Nicolson. The complete Minitrack network employs similar stations atBlossom Point, Maryland; Antigua, West Indies; San Diego, California; Quito, Ecuador; Lima, Peru; Antofagasta and San-tiago, Chile; Woomera, Australia; Esselen Park, South Africa; and Fort Myers, Florida, all of which are linked to the communica-tions and control centre at Goddard Space Flight Center. Wink- This calibration camera is mounted at the centre of the tracking aerial system at Winkfield. Periodic checks on the accuracy of the system will be made in conjunction with aircraft flying over the station field is one of four further stations established to extend the network's high-latitude coverage: the other three will be located at Fairbanks, Alaska; East Grand Forks, Minnesota; and St Johns, Newfoundland. NUCLEAR ROCKET HAZARDS AS the day approaches when space vehicles may be launchedin part by nuclear power, and the equipment in them may be driven entirely by this means, concern is growing in the UnitedStates over the possibility of accidents during launching and flight and the radioactive contamination that could result. The stepsthat NASA, the Atomic Energy Commission and other government agencies are taking to anticipate such a possibility was dis-cussed in Cincinnati, Ohio, on January 11 at a joint meeting of the Southern Ohio Section of the American Rocket Society and theCincinnati Radiation Society. The speaker was Lt-Col Joseph A. Connor Jr, USAF, formerly of the medical staff of George Wash-ington University Hospital in Washington, DC and now Chairman of the Aerospace Nuclear Safety Board of the US Atomic EnergyCommission. Col Connor claimed that the problem had been over-emphasizedby some, that weapons testing in the world to date had contributed only 5-10 per cent to the background radiation level found in mostplaces in the world, and that the rest was made up of radiation from other, natural sources. "Furthermore," he said, "there isless reason to be concerned with radioactive materials from nuclear rockets being tested in Nevada today than there is from weaponstesting, since the amount of radioactive waste from a nuclear rocket is several magnitudes lower than from a nuclear weapon."He went on to note that there was concern in both the USA and Russia on the extensive testing of the many nuclear-powereddevices that may become associated with spaceflight. "As a result," he added, "both countries wish to see nuclear power forspace work carried on in a responsible manner." ; In answer to a question, Col Connor said that nuclear rockets, [ more likely than not, would be used only as upper-stage boosters.[ He gave two reasons for not using them as first-stage boosters: | (1) Danger to man's environment from radioactive materials; (2)the all-but-impossible task of optimizing a rocket nozzle to operate efficiently at both ground level and high altitude. For reasonsof economical operation as well as hazard problems, therefore, it appeared that nuclear rockets would not be employed near thesurface of the Earth. Testing of nuclear rockets, however, posed the contaminationproblem from a different standpoint. For obvious reasons, nuclear rockets would have to be tested on the ground at least during partof their development. Col Connor believed that such testing programmes might be conducted quite safely on the ground,perhaps at a remote launch site such as offshore from Cape Canaveral in the Atlantic, or offshore from Vandenberg AFB inthe Pacific. "The problem of radioactivity would be no more severe than that associated with a nuclear airplane that mightbe operated for a span of time," he declared. He noted that a nuclear rocket would not have the scattering effect in the loweratmosphere that a nuclear aircraft would have. Col Connor indicated that his conclusions with respect tonuclear rockets were based in large part on tests made with the KIWI-A reactor at the Nevada Proving Grounds. By injectinga JATO bottle into the upshooting airstream from the reactor, a clearly identifiable cloud had been formed in the atmosphere sothat the spread of radioactivity could be checked in the air by aircraft flying through the cloud. These tests had shown that theproblem would not be serious with the KIWI-type reactor. When it came to flight-testing the KIWI-type reactor, somequestions had yet to be answered as to what to do with it if the aaturn booster ended up in an undesirable orbit. "We can't havea hot reactor of such size returning to Earth, especially since it employs large amounts of non-ablative graphite that would notburn up in the atmosphere," the speaker commented. Nor was it considered desirable to blow up the reactor in space,since this would leave a substantial amount of radioactive material whirling around. It might prove more advisable to send thevehicle into a much higher orbit, if possible, and then simply leave it there and allow the reactor gradually to run down of itsown volition. A number of Saturn test shots might have to be made simply to work out control techniques and devices forhandling and perhaps destroying nuclear rockets in space, with the least possibility of causing contamination. With the nuclear-powered aircraft it was indicated that, in acrash in which the reactor was melted down, as much as 25 per cent of the fission products might escape. In case of a runawayengine, some 75 per cent of the full 1,000 hours of life of the engine might get away, which would create about 25R emergencydose of radioactivity in the centre of the resulting cloud. Present plans call for nuclear aircraft to be flown only in daytime, in goodweather, and from remote bases on courses that lead over water. All reactors have been so designed that they will not go critical ifimmersed in water or rocket fuel. Because they will be so important to space research, work hasbeen done to check the safety features of nuclear power generators of various types that are being developed under the SNAP pro-gramme. As many as ten SNAP-series power generators are known to be under development or on test, and others are thoughtto be in various stages of development. One of the better known of the series, SNAP-2, like all its even-numbered sisters, is poweredby a nuclear reactor. SNAP-3, like its odd-numbered sisters, derives its power from isotopes. SNAP-2 is small enough to fit inside a five-gallon drum, pro-duces 3kW for one year, and has been developed by Atomics International for eventual use in Discoverer, Samos and Midassatellites. SNAP-3 is rated at three watts, and the first unit has been operating since January 17, 1959, when it was first shown tothe public by the US President. Because of the phobia that has developed in the USA over radiation hazards, however, none ofthe SNAP series so far has been used in space, despite the fact that more-powerful and longer-lasting space power sources arebadly needed. As far as safety in their use is concerned, SNAP units are all programmed to burn up on re-entry to the Earth'satmosphere, so that there should be no danger of contamination resulting when a vehicle equipped with a SNAP device re-enters. Col Connor said that studies had shown that the skin wouldburn off a SNAP vehicle as it re-entered the atmosphere at 320,000ft and, by the time it reached 300,000ft, only the reactorand shield would be left. Since these parts were held together by fuseable links that melt and burn at 2,500°F, the fuel elementof the reactor would come apart at 280,000ft. At 220,000ft, the reactor fuel elements would be reduced to meteorite size and at100,000ft they would be down to micron size or less. For launching purposes, space vehicles with SNAP power unitsaboard might best be launched from Vandenberg AFB in Cali- fornia, so that they could be shot into space while over water forthe most part. The most dangerous time during a launch would be when the space vehicle was between zero and 10,000ft but,even if an abort occurred under these circumstances, tests indicated that SNAP power units posed no particular problem. Theycould withstand a booster explosion and fire with temperatures as high as 6,000 °F on the launching ramp with no damage to theall-important, radioactive fuel core. Cores were being used in SNAP devices that could take from 2,000°F to 4,000°F for sixminutes without failure. Shock-tests carried out with TNT also had been found to causeno damage to the cores of SNAP units. Rocket sled tests in which
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