(False colour image of Titan – Photo Credit: NASA/JPL-Caltech/University of Arizona/University of Idaho)
NASA’s Cassini spacecraft has successfully performed a close flyby of Titan, Saturn’s moon. In the process, the craft bounced signals off Titan to reveal important details about its surface.
This maneuver marked the 103rd Titan flyby for Cassini as the probe skimmed just 2,274 miles above the moon’s surface at a speed of 13,000 mph.
A team of scientists and engineers carefully guided the spacecraft into an orbit that allowed it to bounce a radio signal off the surface of Titan towards Earth. The signal was received by a NASA Deep Space Network land-based telescope array, 1 billion miles away from Cassini.
Essam Marouf, a member of the Cassini radio science team, explained: “We are essentially using Titan as a mirror…And the nature of the echo can tell us about the nature of Titan’s surface, whether it is liquid or solid, and the physical properties of the material.”
(Artists conception of Cassini’s radio bounce – Photo Credit: NASA/JPL-Caltech)
Titan is the second-largest moon in our solar system, after Jupiter’s moon Ganymede. It is one of the most Earth-like bodies scientists have ever encountered as the moon has a thick atmosphere and a system of liquid-hydrocarbon seas and lakes on its surface.
However its surface is far too cold to sustain liquid water, therefore Titan’s lakes and seas are believed to be made of liquid methane or ethane.
These predictions are mostly based on the fact that methane and ethane would take on a liquid state in Titan’s known conditions as there has been no direct observation of the lakes until now.
“There is no really direct measurement that tells us what they are exactly,” Marouf said. “If the data from this morning is good enough, it will tell us what these liquids really are.”
Marouf gathered with other members of Cassini’s radio science team in a control room at the Jet Propulsion Laboratory to await Cassini’s new data as it was received by the Australian radio telescope.
Although they could not analyze the data as it was received, the team were able to tell that Cassini’s radio bounce was successful as the signal was deemed clear enough to be analysed at a later date.
A similar radio bounce was performed on Titan’s surface on May 17 where Cassini’s signal allowed researchers to collect information from Ligea Mare and Kraken Mare, two of the largest bodies of liquid on Titan.
However on this occasion, Cassini bounced its radio signal off an area between two seas where radar images had previously confirmed smaller liquid regions similar to rivers, lakes and channels.
“This kind of experiment takes a meticulous kind of preparation to first know where to look, and then design the maneuvers,” Marouf said. “There are many pieces that have to work flawlessly to end up with the data”.
The team hopes to look over the data as soon as possible and share its results at a Cassini science team meeting in the Netherlands next week.
The Solar System & Beyond 