European space agency officials say the Huygens space probe has successfully entered the atmosphere of Saturn's moon Titan in the final stage of a seven-year journey.

The probe -- operated jointly by the American, European and Italian space agencies -- deployed a huge parachute today (Friday) for its descent toward the surface.

Huygens is collecting data on the composition of Titan's atmosphere and relaying the information to the probe's parent craft, Cassini, for transmission to Earth.

Titan is the only moon in the solar system known to have a significant atmosphere. Scientists believe conditions on Titan are similar to those here on Earth before life evolved, and could help them understand the origin of our atmosphere.