April 19th 2013 Sol 250

Even though Curiosity and its robotic arm are parked during Conjunction, the thermal control system continues to operate. Through the martian seasons (currently southern summer) Curiosity has to survive a temperature range of -120oC to +30oC.  The engineers who build the thermal control system (Birur et al. From Concept to Flight: An Active Fluid Loop Based Thermal Control System for Mars Science Laboratory Rover ) identified major thermal challenges of the MSL rover including: 1. Protecting the sensitive electronics, battery, and science instruments from the extreme cold of martian nights, 2. Handling extremely limited electrical power available for the rover for surface operations. 

The plutonium heat source RTG  generates not only ~120 W of electrical power but also about 2000 W of heat.  The tubing that carries pumped fluid from the RTG maintains temperatures above -40C so that we can operature the instruments.