A window for use in a supersonic or hypersonic target-tracking missile, said window being transparent to electromagnetic radiation in a desired frequency range, comprising, a plurality of window layers (12, 14) which support each 2827 ט" ו בכסליו התשס" ד - December 10, 2003 other and which are commonly supported, each of said window layers having a surface facing a surface of another of said window layers; said window layers being fixedly interconnected with said surfaces; and said window layers consisting of materials having different thermal coefficients of dilation, such that, with the temperature gradient appearing in said window during supersonic or hypersonic flight resulting in different temperatures for different layers, substantially identical thermal dilatations are achieved in each of said different temperature window layers to reduce mechanical stresses due to temperature during supersonic or hypersonic flight as compared to a continuously homogeneous window.
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