In this talk I will focus on our team’s recent development of the Spacecraft Atmosphere Monitor (SAM), a miniaturized Gas Chromatograph Mass Spectrometer slated to be commissioned as a Technology Demonstration Unit on the International Space Station in early 2019. The sensor system for this instrument consists of a quadrupole ion trap mass spectrometer coupled with a MEMS preconcentrator, gas chromatograph, and valve system. The SAM has been designed to monitor major constituents as well as trace organic contaminants in the atmospheres of crewed spacecraft. The requirements of spaceflight have placed stringent constraints on the instrument design which have led to a highly-intentionally designed vacuum system. The vacuum chamber is manufactured by a custom additive process and is equipped with novel differential pumping and gas inlet architecture. The design of this vacuum system will be detailed and preliminary data will be presented.