Cassini Spacecraft Takes Deepest Dip Yet in Titan's Atmosphere
Artist's concept of Cassini's flyby of Saturn's moon Titan. The spacecraft flies to within 547 miles (880 kilometers) of Titan's surface during its 71st flyby of Titan, known as "T70," the lowest in the entire mission.
Credit: NASA/JPL-Caltech

NASA's Cassini spacecraft made its deepest foray into the atmosphere of Titan Sunday, finding the hazy shroud around Saturn's largest moon to be a bit thicker than scientists anticipated.

Cassini made its closest approach to the Saturnian moon Sunday night at 7:45 p.m. Pacific Time while mission scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., awaited news of this latest flyby just 547 miles (880 km) above the surface of Titan.

Cassini has been studying Titan and other Saturn moons, as well as the ringed planet itself, since it arrived at the gas giant in 2004. Its European lander Huygens touched down on the Titan surface in January 2005.

But despite the thicker-than-expected atmosphere, Cassini stayed on target and within the safety margins during the latest Titan flyby, returning valuable science data to the researchers on Earth.

"We have data playbacks today at two different Deep Space Network stations to make sure we have ? as we say here ? both belts and suspenders," Webster wrote. "Engineers will also go back to analyze the data with the scientists to see just how dense the Titan atmosphere turned out to be at our flyby altitude."

This flyby marked Cassini's 71st swing past Titan. During the rendezvous, Cassini flew below Titan's ionosphere, which is the layer of electrons and other charged particles that make up the upper part of Titan's atmosphere.

Mission scientists were hoping to scan Titan to look for any potential magnetic signatures originating from the hazy moon.

The anticipation among Cassini's science team was so high that Webster said waiting to hear from the probe during the flyby was almost too hard to bear. It takes signals about 78 minutes to make the trip to Earth from Titan, she added.

"One of the 34-meter antennas at the Deep Space Network's Goldstone complex, DSS-24, was pointed at Saturn and listening for the signal that was expected to be here in just a few minutes," Webster wrote. "The data would be arriving at my computer as quickly as they could be sent back to Earth, though there was an agonizing hour-and-18-minute delay because of the distance the data had to travel."

By coincidence, Cassini was able to perform the flyby with its main antenna pointed at Earth, which optimized communications with its mission control room, NASA officials have said.