Abstract: Cassini’s Composite Infrared Spectrometer (CIRS) observed both of Rhea’s polar regions during a close (2000 km) flyby on 9th March 2013 during orbit 183. Rhea’s southern pole was again observed during a more distant (51,000 km) flyby on 10th February 2015 during orbit 212. The results show Rhea’s southern winter pole is one of the coldest places directly observed in our Solar System: surface temperatures of 25.4 +/-7.4 K and 24.7 +/-6.8 K are inferred from orbit 183 and 212 data, respectively…