Disclosed is a mechanism to exhaust refrigerant vapor resulting from operation of a thermal management system that is used to cool a thermal load by a vehicle, such as an airborne vehicle. The thermal management system includes an open circuit refrigeration system featuring a receiver configured to store a liquid refrigerant fluid, an evaporator configured to extract heat from the thermal load that contacts the evaporator, and an exhaust line, where the receiver, the evaporator, and the exhaust line are connected to provide an open refrigerant fluid flow path. Other implementations of open circuit refrigeration systems include the use of a gas receiver, a pump and an ejector are also described, as are other mechanisms to exhaust refrigerant vapor resulting from operation of the thermal management system.