NASA's Cassini spacecraft sent the closest-ever images of Saturn on Thursday after surviving its first plunge inside the planet's rings, the U.S. space agency said.
A stream of pictures showing Saturn's swirling clouds, massive hurricane and odd six-sided vortex weather system were transmitted back to Earth by Cassini, which has been exploring Saturn for 13 years.
Now in its final laps around Saturn, Cassini dove through the narrow gap between the planet and its innermost ring on Wednesday, where no spacecraft has ever gone before. It was the first of 22 planned close encounters to bring the robotic probe into unexplored territory between Saturn's cloud tops and its rings.
"Cassini spacecraft has once again blazed a trail, showing us new wonders and demonstrating where our curiosity can take us if we dare," National Aeronautics and Space Administration planetary sciences chief Jim Green said in a statement.
Cassini is expected to photograph several small inner moons and study the planet's winds, clouds, auroras and gravity. The information could help scientists find the source of Saturn's magnetic field, determine how fast the gas giant rotates and figure out what lies beneath its layers of clouds.
NASA officials are not certain Cassini will survive all its ring dives. The gap between Saturn and the rings is about 1,500 miles (2,400 km) wide and likely littered with ice particles.
Cassini is traveling through the gap at a relative speed of about some 77,000 mph (124,000 kph) so even small particles striking the spacecraft can be deadly.
To protect itself, Cassini's dish-shaped communications antenna was temporarily repositioned to serve as a shield. The spacecraft will make similar maneuvers during its subsequent dives, the next of which is scheduled for Tuesday.
On its final dive on Sept. 15, Cassini is slated to destroy itself by flying directly into Saturn's crushing atmosphere.
During its first pass inside the rings, Cassini came within about 1,900 miles (3,000 km) from the top of Saturn's clouds and within 200 miles (300 km) of its innermost ring.
Cassini has been probing Saturn, the sixth planet from the sun, and its entourage of 62 known moons since July 2004, but is running low on fuel.
NASA plans to crash the spacecraft into Saturn to avoid any chance Cassini could someday collide with any ocean-bearing moons that have the potential to support indigenous microbial life.