The calculated rate of significant illness or injury on submarines, Antarctic expeditions, military aviation and space flight was found to be approximately 0.06 cases per person-year.[13] If we use this data to evaluate the rate of occurrence of a medical emergency to a 2.5-year Mars mission, assuming six crew members, we get a rate of 0.9 cases per people/mission.[13] In other words, one significant medical event could be expected per Mars mission.