... a tennis ball (from) 15 miles away moving at three times the speed of sound ...
... might reach me before my drive spooled up and I entered super cruise but anything much further out wouldn't be effective.
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Any kinetic or explosive munition more than 10 seconds away isn't a threat unless it (or the delivery system) can also mass lock you. At similar distances I suspect the inverse square law would limit the effectiveness of energy weapons as I doubt that even in 3300 the perfect collimator exists. Hence, presumably, the emphasis on dogfighting in ED (if you really need an in-game justification).