A propulsion system for an aircraft, the propulsion system comprising; at least one core engine (20; 20A, 20B) including a core flow path in communication with a compressor section, combustor section and a turbine section, wherein a high energy exhaust gas flow is produced in the combustor section and expanded through the turbine section to drive the compressor section; a first bottoming cycle system including a bottoming working fluid flow in thermal communication with the high energy exhaust gas flow generated by the at least one core engine (20; 20A, 20B), the first bottoming cycle is configured to recover power from the high energy exhaust gas flow in a first engine operating condition and in a second engine operating condition; and a second bottoming cycle system including the bottoming working fluid flow in thermal communication with the high energy exhaust gas flow, the second bottoming cycle system configured to recover power from the high energy exhaust gas flow in the first engine operating condition, wherein: each of the first bottoming cycle system and the second bottoming cycle system includes a bottoming compressor (80A, 80B) and a bottoming generator (82A, 82B) driven by a bottoming turbine (78A, 78B); the propulsion system further includes a first valve assembly controlling bottoming working fluid flow to the bottoming turbine (78A, 78B) of the first bottoming cycle and the second bottoming cycle and a second valve assembly configured to control bottoming working fluid flow from the bottoming compressor (80A, 80B) of the first bottoming cycle and the second bottoming cycle; and the propulsion system further includes a controller configured to operate the first valve assembly and/or the second valve assembly to stop bottoming working fluid flow to the second bottoming cycle system in response to an indication that the high energy exhaust gas flow has less thermal energy than desired to operate both of the first bottoming turbine and the second bottoming turbine. at least one core engine (20; 20A, 20B) including a core flow path in communication with a compressor section, combustor section and a turbine section, wherein a high energy exhaust gas flow is produced in the combustor section and expanded through the turbine section to drive the compressor section; a first bottoming cycle system including a bottoming working fluid flow in thermal communication with the high energy exhaust gas flow generated by the at least one core engine (20; 20A, 20B), the first bottoming cycle is configured to recover power from the high energy exhaust gas flow in a first engine operating condition and in a second engine operating condition; and a second bottoming cycle system including the bottoming working fluid flow in thermal communication with the high energy exhaust gas flow, the second bottoming cycle system configured to recover power from the high energy exhaust gas flow in the first engine operating condition, wherein: each of the first bottoming cycle system and the second bottoming cycle system includes a bottoming compressor (80A, 80B) and a bottoming generator (82A, 82B) driven by a bottoming turbine (78A, 78B); the propulsion system further includes a first valve assembly controlling bottoming working fluid flow to the bottoming turbine (78A, 78B) of the first bottoming cycle and the second bottoming cycle and a second valve assembly configured to control bottoming working fluid flow from the bottoming compressor (80A, 80B) of the first bottoming cycle and the second bottoming cycle; and the propulsion system further includes a controller configured to operate the first valve assembly and/or the second valve assembly to stop bottoming working fluid flow to the second bottoming cycle system in response to an indication that the high energy exhaust gas flow has less thermal energy than desired to operate both of the first bottoming turbine and the second bottoming turbine. each of the first bottoming cycle system and the second bottoming cycle system includes a bottoming compressor (80A, 80B) and a bottoming generator (82A, 82B) driven by a bottoming turbine (78A, 78B); the propulsion system further includes a first valve assembly controlling bottoming working fluid flow to the bottoming turbine (78A, 78B) of the first bottoming cycle and the second bottoming cycle and a second valve assembly configured to control bottoming working fluid flow from the bottoming compressor (80A, 80B) of the first bottoming cycle and the second bottoming cycle; and the propulsion system further includes a controller configured to operate the first valve assembly and/or the second valve assembly to stop bottoming working fluid flow to the second bottoming cycle system in response to an indication that the high energy exhaust gas flow has less thermal energy than desired to operate both of the first bottoming turbine and the second bottoming turbine.