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questions about the observation of the planet Earth from space, usually for scientific, technical, or other well-defined reasons, or about the spacecraft that do this. This tag is usually used for systematic observations, but it could also apply to a questions on specific images or photos observing something unusual requiring analysis.

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The highest frequency is gamma rays, dedicated to detecting nuclear explosions on Earth. These have provided some knowledge of space events as well, due to their low selectivity, but they are intended …
answered Aug 30 '13 by PearsonArtPhoto
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4 is actually the number, as is documented in Patent US4854527. It is a tetrahedral constellation using elliptical orbits. In one hemisphere two have their further point, while the other two have the …
answered Mar 11 '15 by PearsonArtPhoto
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There is a network of satellites designed to detect ballistic missile launches. The key feature in each of these is very high temperatures moving at fast speeds. Thus, the easiest way to look for them …
answered Mar 18 by PearsonArtPhoto
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The ISS, at it's closest, is, say, 500 km (Can be a bit closer, but let's not stretch it). That would require a FOV of 1/500, or about 0.1 degrees. That would require a camera with a lens of about 200 …
answered Jun 20 '16 by PearsonArtPhoto
2
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These are almost certainly for military applications, as they are the only ones that require short turn around and short term usage. This has been a dream of military for some time. Most of this resea …
answered Mar 10 '16 by PearsonArtPhoto
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The videos are all very short The first one is 17 seconds, while the others don't seem to be any bigger. The altitude is just over 500 km. The distance moved during that time will be about 1250 km. As …
answered Apr 16 '18 by PearsonArtPhoto
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A few things to consider: Refraction- The atmosphere will bend the light somewhat, which might cause it to take longer. Speed of light changes- Light moves a bit slower when going through more of th …
answered Jan 3 '18 by PearsonArtPhoto