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Titan Flyby (T-102): Bouncing Radio Waves off Titan’s Lakes Again

Titan's south polar vortex mimics the moon itself, creating an elegant crescent within a crescent. Situated above the surrounding polar atmosphere, the raised walls along the sunward side of the vortex just catch the grazing sunlight, creating a crescent of its own.

During Cassini’s June 18 Titan flyby (T-102), the Radio Science (RSS) instrument passed its signal through the atmosphere of Titan, and sent it back and forth to the Deep Space Network (DSN) stations on Earth until the signal was fully blocked—or occulted—by Titan itself. These observations of Titan’s atmosphere will help answer these three main science questions:

What are the seasonal changes in Titan’s high latitude atmosphere? Specifically, what is the temperature structure, and how does the winter polar vortex form and breakup?
Through measuring the tropospheric (the layer of the atmosphere closest to the surface) temperature profiles, how are Titan’s tropospheric winds characterized?
What is Titan’s atmospheric and Ionospheric structure?

This flyby also presents another opportunity to bounce signals off the surfaces of the northern lakes. Known as a bistatic scattering experiment, the results can be used to reveal details about the nature and composition of the lakes’ liquid surface, and how those characteristics vary from place to place. The T-102 flyby first grazed the edge of Ligeia Mare, the second largest liquid body of Titan. It then continued onto the largest body, Kraken Mare.

The radio signals were sent from Titan back to Earth's Deep Space Network (DSN) stations until the signal was fully blocked—or occulted—by Titan itself. The bistatic experiments occurred both before and after the occultation, and the observations over Kraken Mare and Ligeia Mare took place after the occultation.

Date
June 18, 2014

Altitude
2,274 miles (3,659 km)

Speed
13,000 mph (5.6 km/sec)