Butyl rubber inner tubes used in military aircraft must meet the property specification requirements of Aerospace Standard AS50141. Their nominal shelf life is 10 years from the date of manufacturing but it is known that this value can be influenced by the butyl type (i.e. regular versus halogenated). In part 1 of this investigation, a butyl rubber inner tube will be evaluated for its shelf life. Accelerated heat aging took place from 40 to 120°C for varying lengths of time. Hardness and mechanical properties were measured on the aged samples. Double Quantum Nuclear Magnetic Resonance was employed to elucidate crosslink density and distribution changes as a function of heat aging. Time-Temperature Superposition (T-TS) of the aged data coupled with the Arrhenius approach were used to determine an approximate shelf life. The low temperature aging data were more appropriate to this end due to the presence of non-Arrhenius aging behavior. Crosslinking reactions are more prominent in the low temperature regime whereas chain scission reactions appear to occur more frequently at higher temperatures.