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The fruit fly \emph{Drosophila melanogaster}, has a storied history of over a century as a model organism for genetic and behavioral studies. In more recent decades, it has also been used as a model organism for immune system and cardiac function, and it is emerging as a model for host-gut microbiome interactions. While Drosophila cardiac anatomy is quite different from that of a human, it does share some functionality (e.g., ion channels) and many of the genes involved in building a heart are shared between flies and humans \cite{Cammarato_2011}\cite{Wolf_2011}. As in humans, cardiac function declines over the life span of the fly \cite{Ocorr_2007}. However, the typical lifespan of a fly is 45-60 days, allowing for quick study of age-dependent decline in organ function. \emph{Drosophila melanogaster} has also been a frequent flier to low Earth orbit, where it has been used to study the effects of spaceflight and microgravity on innate immunity \cite{Taylor_2014} \cite{Marcu_2011}, DNA mutation \cite{Vaulina_1982}, and development \cite{Marco_1992} \cite{Abbott_1992}.   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 axenic (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 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.