Cassini, NASA's mission to investigate the Saturnian system was launched successfully on October 15, 1997. The cruise period from launch until Saturn arrival takes the spacecraft through a wide range of solar/thermal environments (0.67 astronomical units [AU] to 10 AU). The thermal control approach, which consists of thermal design features and operational constraints, must therefore maintain hardware temperature limits throughout this wide range of environments.The off-sun exposure flight experience with interplanetary spacecraft at relatively close heliocentric distance is very limited. Cassini's ability to perform off-sun maneuvers relies heavily on the large thermal capacitance of the spacecraft's central body and the relatively short off-sun durations required for these maneuvers. The post launch execution of the first trajectory correction maneuver (TCM-1) was the first opportunity to validate the spacecraft off-sun capability and to enhance the thermal math model simulation capability.