Thermal management systems and methods for cooling a heat load with a refrigerant fluid managed with a closed-circuit cooling system

A thermal management system, comprising:

• a closed-circuit cooling system configured to supply a cooling medium through a closed-circuit fluid flow path;
• and
• an open-circuit refrigeration system, comprising:
• a receiver comprising a receiver inlet and a receiver outlet, the receiver configured to store a refrigerant fluid, the receiver in thermal communication with the closed-circuit fluid flow path of the closed-circuit cooling system to cool the refrigerant fluid with the cooling medium;
• an evaporator coupled to the receiver outlet, the evaporator configured to receive the cooled refrigerant fluid from the receiver outlet and to extract heat from at least one heat load in thermal contact with the evaporator;
• a flow control device configured to control a temperature of the at least one heat load;
• and
• an exhaust line, with the receiver, the evaporator, the flow control device, and the exhaust line coupled to form an open-circuit refrigerant fluid flow path.