It's been 10 years since the bus-sized Cassini orbiter began its mission to Saturn - and for scores of scientists and engineers, the birthday is a cause for celebration. But this isn't like most birthday parties: Today, it's the honoree that's providing the presents.

The most treasured goodies include a fresh crop of pictures showing the ringed planet as well as its moons, and videos that show Cassini's recent flyover of the two-toned moon Iapetus as well as the shepherd moon Prometheus' touch-and-go with Saturn's F-ring.

When Cassini lifted off from Cape Canaveral Air Force Station back on Oct. 15, 1997, the main topic of conversation was the spacecraft's plutonium-powered generator system. Some worried that "plutonium could rain from the skies" if the Titan 4 rocket blew up during its ascent - but the launch and a subsequent Earth flyby went off without a hitch.

Today, NASA's New Horizons probe is speeding toward Pluto with its own radioisotope-based generators, and NASA is talking about expanding the use of nuclear power on deep-space missions.

Whether or not you're a fan of radioactivity in space, there's no denying that Cassini has been an unqualified success. In today's "Captain's Log" posting on the Cassini imaging team's Web site, team leader Carolyn Porco gushed with gratitude.

"To the thousands upon thousands of fellow explorers who have traveled with us since we departed Earth 10 years ago today, who have followed our adventures across the solar system and into orbit around Saturn and who have since been as awestruck as we have at our findings there, we say, 'Happy Anniversary! It's been a pleasure flying with you!"

Cassini project scientist Dennis Matson was similarly effusive in a NASA report marking the anniversary:

"With Cassini, amazing discoveries have almost become routine. ... Orbiting Saturn, Cassini is in the middle of the greatest natural laboratory accessible to us in space. With its rings, dozens of moons and magnetic environment, Saturn is like a mini-solar system, with Saturn as a stand-in for the sun, and the moon and rings like planets in formation. ..."

Cassini has sent back some amazing sights in the three years since it entered Saturnian orbit - including images of shepherd moons shaping the wispiest of the planet's rings; clear signs of hydrocarbon lakes and seas on smog-shrouded Titan; and most intriguingly, hints of icy geysers spewing forth from the moon Enceladus.

The 10th-anniversary images document some of the latest revelations - and also give you a sense of the Saturnian system's majesty.

But wait ... there's more: The scientists behind Cassini have updated a golfing game that takes you on a tour of Saturn's moons. The game is harder than it looks, in part because you have to take the moons' reduced gravity into account. You can knock a golf ball clear into space if you're not careful.

You can log into Sector 6 and comment on your favorite Cassini pictures - or compare Cassini's sights with historical views of Saturn and other planets as seen by the Voyager probe. The Voyager views go back as far as 30 years.

Will Cassini still be kicking on its 30th birthday? To start with, NASA is on track to extend the probe's mission until at least 2010 - and perhaps to 2012. That extra time could provide an opportunity for a thorough investigation of Enceladus' geysers and other puzzles that astrobiologists would like to crack.

Beyond that time frame, it's anyone's guess what could happen. Cassini could eventually be sent to its doom in Saturn's atmosphere (a la Galileo at Jupiter), or crashed into a moon (like Lunar Prospector and SMART-1), but NASA is already aware of the potential downsides - including problems that might be posed by those plutonium-bearing generators.

I'm pulling for Cassini to be put in mothballs for a future mission, just as the Deep Impact and Stardust probes were. But that's a question for another day, a long time from now. For now, let's enjoy the greatest hits from Cassini's first 10 years, and look forward to many more hits to come.

Update for 12:30 p.m. ET Oct. 17: Cassini imaging team leader Carolyn Porco got back to me with these additional e-mail comments about the mission's future:

"About the years ahead ... what I'm most looking forward to are the close-in looks at Enceladus, our continued unraveling of the surface of Titan (which has turned out to be so geographically diverse that it's bound to have other surprises in store), and being able to answer some outstanding questions that our initial examinations of the rings have left us with.  Being able to pose questions in orbit and have the opportunity to answer them in short order has been a giant step forward for us.  It's a luxury, really."