Cassini on the launch pad.

Standing majestically in Florida's early morning moonlit hours, the Titan IV-B/Centaur launch vehicle carrying the Cassini-Huygens spacecraft was patiently awaiting the opening of the 140-minute launch window. Two days earlier, high winds prevented the launch. But on that morning, the 15th of October 1997, conditions were favorable.

Exactly 10 minutes before the opening of the launch window, the much-anticipated announcement came through.

All systems are go!

Cheers followed the announcement. Hearts raced. This time, nature's elements were in sync with the launch of the most sophisticated spacecraft ever built.

At the five-minute mark, and then again at the two-minute mark, an excited George Diller, Kennedy Space Center's announcer, repeated the good news. "The status is 'go' across the board!"

At Launch Complex 40 on Cape Canaveral Air Station, the Mobile Service Tower retracted. The two upgraded solid rocket motors mounted at the base prepared to blast the giant spacecraft out of Earth's atmosphere.

Ten, nine, eight ...

Cassini takes to the sky.

Basking in the early morning light, the imposing rocket stood proudly, as tall as a 22-story building. Carefully wrapped inside the launch vehicle were the Cassini orbiter -- built by the Jet Propulsion Laboratory -- and the Huygens probe, funded and built by the European Space Agency.

Six, five, four ...

After years of labor, tests, designs and redesigns, checks and double checks, more than 8,000 technicians and engineers in the United States -- and thousands more across 17 countries -- held their breaths, anxious to see the fruits of their labor go up in space.

Three, two, one ... Lift off!

Perfectly on schedule, at 4:43 a.m. EDT, the 5,650-kilogram (6-ton) spacecraft began its vertical ascent. Echoed by cheers from the crowd and the loud roars of the engines, furious flames propelled the spacecraft. In a matter of seconds, the full moon paled. Cassini-Huygens was indeed on its way toward Saturn. Scientists from every corner of the globe watched in glorious anticipation.

You can watch a video of the launch.

Two minutes and 23 seconds later, the announcer reported that the flawless launch sequence continued with the separation from the Titan IV/B launch vehicle. By then, the spacecraft was already at an altitude of 91,440 meters (360,000 feet) and traveling at 7,046 kilometers (4,378 miles) per hour.

Family and friends watch the launch.

That announcement received the loudest cheers and a few tears of joy in California at JPL's von Karman Auditorium, packed with family and friends gathered to witness the historical moment on the big screen, even though it was nearly 2 A.M.

The Centaur upper stage separated successfully at 42 minutes and 40 seconds into the flight. Flying on its own for the first time, the Cassini-Huygens spacecraft 10 minutes later successfully opened its communications link with NASA's Deep Space Network tracking complex near Canberra, Australia.

All systems on the spacecraft were operating normally, and data confirmed the precision of the launch: the energy provided to the spacecraft by its launch vehicle was accurate to within one part in 5,000. At better than 0.04 degrees, any deviation in the trajectory (path) of the spacecraft was described as "insignificant."

DVD with over 616,000 signatures

Carrying a disk with signatures of more than 616,000 well-wishers from 81 nations, the Cassini-Huygens spacecraft was finally on its long journey to Saturn. Finally, the united efforts of three space agencies will give humankind a sophisticated science laboratory in the orbit of the most fascinating planet in the solar system. The spacecraft will collect data for Cassini's four year prime mission and beyond.

With its majestic rings, dozens of frozen moons and a huge magnetosphere, Saturn has intrigued human imagination for centuries. The planet's sheer distance from us created significant challenges, and while three spacecraft in the past two decades have succeeded in flying that far away from Earth, these voyages were only appetizers in the voracious appetites of the science community.

Scientists' countries

With Cassini-Huygens finally on its seven-year route toward the vast Saturnian system, scientists could finally enjoy the main course. Starting in July 2004, one of the most sophisticated spacecraft ever sent into space began to bring them a nine-course meal: a feast of images and data that will answer many questions about this mysterious corner of our solar system.

Truly an international enterprise, the mission enlisted help from 17 nations. Cassini was built and is managed for NASA by the Jet Propulsion Laboratory. The European Space Agency contributed the Huygens Probe. The high-gain antenna and elements of several of Cassini's science instruments were provided by the Italian Space Agency. More than 260 scientists from 17 countries participate in the mission.