pierre (01/29/83)
During the past couple of weeks, we heard a lot about the Soviet satellite that was going to fall on our heads. Does anyone remember that the U.S. have some experience with falling nuclear-powered satellites ? A suggested reading is "Science", the magazine of the American Association for the Advancement of Science, January 7, 1983. It reports one case, among others, in 1964, when a plutonium-powered Transit navigational satellite fell back into the ocean. After that period, the level of plu- tonium in the atmosphere increased threefold.
henry (02/06/83)
One minor amendment to hcr!pierre's report. One must be careful to read news stories for precise meaning sometimes, and there was one rather deceptive bit of wording in the Science report about the Transit incident in 1964. It did not say that the level of plutonium in the atmosphere increased threefold; it said that the level of plutonium-238 in the atmosphere increased threefold. Plutonium-238 is a rare isotope even by plutonium standards; the major plutonium isotope is 239. It's no surprise that there is very little Pu-238 in the atmosphere normally, and that a few kilos of it from a burning satellite could thus make a large difference. Would be interesting to know how much difference it made to the total plutonium level, but they didn't mention that. Maybe it didn't sound spectacular enough. For that matter, there isn't very much plutonium of any sort in the atmosphere normally. Most of what there is, is Pu-239 from atmospheric nuclear-weapon tests. A threefold increase sounds scary, but if it's the difference between negligible and trivial, who cares? Remember that there is no shortage of radioactive junk in the atmosphere from perfectly natural causes, and that plutonium is one of the lesser worries even in nuclear-weapon debris. The most interesting number would be how much the Transit event upped the total radioactive-element level in the atmosphere (yes, I know that concept is full of apples-vs-oranges problems, but one can try). I can't say that I approve of radioactive contamination of the atmosphere I breathe, but I prefer to read news reports by people who've done their homework. Henry Spencer U of Toronto