Bacillus pumilus SAFR-032 was originally isolated from the Jet Propulsion Lab Spacecraft Assembly Facility and thoroughly characterized for its enhanced resistance to UV irradiation and oxidative stress. This unusual resistance of SAFR-032 is of particular concern in the context of planetary protection and calls for development of novel disinfection techniques to prevent extraterrestrial contamination. Previously, spores of SAFR-032 were exposed for 18 months to a variety of space conditions on board the International Space Station to investigate its resistance to Mars conditions and space travel. Here, proteomic characterization of vegetative SAFR-032 cells from space-surviving spores is presented in comparison to a ground control. Vegetative cells of the first passage were processed and subjected to quantitative proteomics using tandem mass tags. Approximately 60% of all proteins encoded by SAFR-032 were identified and 301 proteins were differentially expressed among the strains. The functional analysis of differentially expressed proteins revealed the downregulation of proteins related to carbohydrate transport/metabolism and energy production/conversion, which was validated by enzymatic assays. The same space-surviving strains showed upregulation of proteins related to competitive growth and stress response. Observed protein profiles provide insights into the possible molecular mechanisms of B. pumilus SAFR-032 to adapt and resist extreme extraterrestrial environments.