The current NASA spaceflight food program encompasses a wide variety of commercial and custom-made edible products. These foods are designed to ensure each crewmember receives the Recommended Dietary Allowance (RDA) of vitamins and minerals to maintain adequate health during the entire spaceflight mission. With the desire for long-duration and exploration-class missions, such as the impending mission to Mars, the retention of important nutrients such as labile vitamins in spaceflight foods is critically important. For this reason, multiple studies were conducted to determine the vitamin degradation behavior of thiamine (vitamin B1) within three spaceflight foods which demonstrated both significant presence and instability of this compound during shelf-stabilization and in storage for two years. All foods were produced based on NASA’s recipes and were either retort sterilized to an equivalent lethality (F0 of 6) or cooked and freeze-dried, then stored anaerobically in aluminized retort pouches. All food products were then stored at -80°C, -20°C, 4°C, 20°C, and 37°C. Vitamin retention was measured in all foods prior to and following thermal processing as well as at regular intervals in storage to discern the degradation kinetics of thiamine, which are assumed to follow a first-order, temperature-dependent trend. A novel and interactive kinetic modeling program, produced by our research group, was utilized to identify the two degradation parameters: decay rate constant at a given reference temperature or kTref, and temperature sensitivity term or cest, for vitamin B1 in each food matrix during thermal processing as well as during storage. In our studies, we revealed the degree of degradation of vitamin B1 in each food following various thermal processes and during two years in storage, including degradation observed in freeze-dried versions of each food product. These kinetic parameters can be utilized to track vitamin degradation over time in mission food storage and to produce optimum thermal processing conditions, preservation techniques, and storage parameters to achieve maximum stability of vitamins B1 in these food products.