Cassini spacecraft one of NASA's star robots

Mimas, the smallest of Saturn's inner moons, casts its shadow into the outer rings of the planet. Equinox on Saturn, when the Sun crosses the plane of the Ringed Planet's equator, and day and night are of equal length, occurs about every 15 years. In the few months before and after Saturn's equinox, several of the planet's inner moons cast shadows on its rings.

 

With Saturn and Earth at the closest point to each other in their orbits around the Sun, spectacular views of the Ringed Planet will be possible for the next few weeks using even a small telescope. But the best views of Saturn and its moons over the past decade have been from the Cassini spacecraft designed by NASA and European space agencies.

The Cassini-Huygens mission and the Mars rovers are star performers in NASA's drive to explore the solar system with robotic technology. Cassini has been exploring Saturn and its moons since 2004, deploying the Huygens lander in 2005 for a successful touchdown on Saturn's surface and sending thousands of images back to Earth since.

Manned spaceflight has many allures, but robotic space missions will have far longer reach at far lower cost for the foreseeable future.

Saturn is the second-largest planet in the solar system, with hallmark rings and more than 60 moons. /NASA images

Time progression images show a storm in Saturn's northern hemisphere raging for more than 18 months.

Saturn's dense, murky atmosphere serves as a backdrop for Rhea, the Ringed Planet's second-largest moon. This view from Cassini looks toward the rings at a 1 degree angle, making the unilluminated side of the rings appear to be a solid straight band.

An infrared image shows a ring of aurora stretching around Saturn's north polar region. Cassini also has captured images of massive hurricane-like storms swirling at Saturn's poles.

The Sun reflects off a liquid methane sea on Titan, the Ringed Planet's largest moon. Titan and Earth are the only known places in the solar system with bodies of liquid on their surfaces.

Twisted fissures show the effect of powerful tectonic forces on Saturn's moon Enceladus.

 

Saturn's largest moon, Titan, appears deceptively small compared to Dione, Saturn's third-largest moon, in this image captured by Cassini.

Titan rises over the Ringed Planet's horizon. Tethys, a relatively small member of Saturn's large and various extended moon family, is a shiny ball of ice spinning around the gas giant.