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Numerous recent studies have suggested a relationship between the animal gut microbiome and both brain \cite{Foster_2013} and cardiac function \cite{Vinje_2014}, including both indirect \cite{Reardon_2014} and direct \cite{Lam_2012} effects on the risk and severity of heart attacks. As new correlations between the gut microbiome composition and disease states in various other organ systems emerge, it becomes increasinly important to take advantage of model systems in which correlations can be tested further for causation \cite{Fritz_2013}; see \cite{Baxter_2014} for a good example. Currently, the ratio of mouse microbiome to Drosophila microbiome publications is greater than 25:1, but there are many advantages to the use of Drosophila as a model for microbiome studies \cite{24983497}, including the relative ease and low-cost of (especially axenic) rearing \cite{Charroux_2012}\cite{Ridley_2013}.  Here, we present the first look at the differences in microbiome composition, in the context of a controlled experiment, between animals reared in a laboratory on the International Space Station and reared in a laboratory on the surface of the  Earth. To do this, we employed 16S rDNA PCR surveys of dissected fly guts, swabs of feces from the surface of fly vials, and the post-dissection carcasses.