(UVIS was much more technologically complex than a fridge and was destroyed along with the rest of Cassini in 2017, when the craft plummeted into Saturn’s atmosphere.) Taken during flybys of Rhea in 2007 and 2011, the data Cassini collected indicated an unidentified spectroscopic signature emanating from the icy moon.
The team doesn’t think this happened, though, as the Rhea flybys weren’t powered by the hydrazine thrusters, which were not firing at the time.
The team argues that if hydrazine wasn’t produced by chemical reactions between ammonia and water-ice on Rhea, it could have sputtered out of Titan’s nitrogen-rich atmosphere and landed on the smaller moon.
“I’ll be curious to see whether NASA’s planned Dragonfly mission will give us a better sense of whether hydrazine could originate on Titan, and if so, whether that hydrazine (or other molecules) could be transported to Saturn’s other moons.â€.