Pasadena, Calif. ? Saturn’s giant moon Titan refused to give up its secrets Friday as the Cassini spacecraft flew by for the first time and peered into its murky atmosphere to try to see its surface.

“It’s not as clear as we’d hoped,” Cassini imaging team leader Carolyn Porco said as unprocessed images transmitted across 900 million miles of space arrived at NASA’s Jet Propulsion Laboratory.

Some things were visible to experts, and Porco was certain that some were surface features. She said processing might draw out more from the images.

“We haven’t applied our full bag of tricks yet,” she said.

Cassini will make many more flybys of Titan and in December will launch a probe that will enter the moon’s atmosphere in January.

Titan was Cassini’s first encounter since the spacecraft began orbiting Saturn this week for a four-year exploration of the ringed planet and many of its 31 moons.

Cassini transmitted about 2 1/2 hours of data and images collected as it passed by Titan at a distance of about 200,000 miles.

Titan images recorded in June from millions of miles away appeared to show linear features that could suggest tectonic activity, Porco said.

The frustrating haze is part of what makes Titan interesting to scientists.

“That haze is kind of an organic goo much like the smog that one might see in Los Angeles, composed of hydrocarbons, and not allowing us to see through to the surface,” said Linda Spilker, the Cassini deputy project scientist.

This true-color image taken by the Cassini spacecraft shows Titan, a moon of Saturn, enveloped in a photochemical smog.