New answers tagged observation
I do not know for sure, but you are viewing the satellites by the reflection of sunlight. As the satellite moves across the sky, the Sun-satellite-you angle changes, therefore there is no reason to expect that the brightness should stay the same. As for why it should fade and brighten again - if you imagine the satellite to consist of a number of surfaces, ...
NASA mission data is archived at a handful of NASA archives. If you do not know which archive a data set is in, then you can search the Master Catalog at the NASA Space Science Data Coordinated Archive (NSSDC). The main astrophysics archives are: HEASARC (High Energy Astrophysics Science Archive Research Center) IRSA (Infrared Science Archives) LAMBDA ...
You're not saying what programming language you're using. If it's Python, or if you could link Python libraries from it, then PyEphem would provide everything you need. http://rhodesmill.org/pyephem/
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