Abstract: A vapor cycle cooling system (10) in accordance with the invention includes a compressor (12) for compressing refrigerant vapor; a condenser (14) receiving compressed refrigerant vapor from the compressor; a fan (18) having at least two controllable speeds for blowing a fluid (16) in contact with the condenser to remove heat from the compressed refrigerant at the condenser to cause the refrigerant to liquify, the speeds of the fan being controllable by a control signal; an expansion valve (22) receiving liquid refrigerant from the condenser which expands the liquid refrigerant; an evaporator (24) receiving the expanded refrigerant which exchanges heat with a fluid stream (26) coupled to a heat load (28); and a controller (20) for generating the control signal, responsive to a sensed evaporator temperature, a sensed ambient temperature and a sensed altitude which controls two speeds of the fan as a function of the sensed temperatures and altitude by generating the control signal.