NASA Celebrates Cassini’s 15 Year Anniversary
Brett Smith for redOrbit.com – Your Universe Online
The $3.3-billion mission lifted off the launch pad on October 15, 1997 and has traveled over 3.8 billion miles since – flying past Venus twice and Jupiter once en route to entering orbit around the ringed planet in 2004.
The mission has provided a treasure trove of interplanetary data that it has transmitted from the depths of space back to Earth: 444 gigabytes of scientific data and over 300,000 images. The craft carries several instruments, including a radar mapper, an infrared spectrometer, an ultraviolet spectrograph and a cosmic dust analyzer.
Information culled from these instruments has been used in more than 2,500 published journal reports, including descriptions of ice water plumes on Saturn´s Enceladus, the hydrocarbon-filled lakes of Titan, and a gigantic storm in Saturn´s atmosphere.
“As Cassini conducts the most in-depth survey of a giant planet to date, the spacecraft has been flying the most complex gravity-assisted trajectory ever attempted,” said Cassini program manager Robert Mitchell in a statement. “Each flyby of Titan, for example, is like threading the eye of the needle. And we’ve done it 87 times so far, with accuracies generally within about one mile, and all controlled from Earth about one billion miles away.”
Mitchell added that 15 years of flight have had their impact on the craft; however Cassini still performs its daily tasks with precision.
“I’m proud to say Cassini has accomplished all of this every year on-budget, with relatively few health issues,” he said. “Cassini is entering middle age, with the associated signs of the passage of years, but it’s doing remarkably well and doesn’t require any major surgery.”
Cassini performs a series of maneuvers as it hurtles around Saturn. The flight instructions are sent from NASA and take into account the numerous gravitational fields in Cassini´s path and its limited fuel supply, 72 pounds of radioactive plutonium.
According to NASA, the 4,700-pound craft still has a long mission ahead as it cruises though middle age. Saturn´s trip around the sun takes 29.7 Earth years and Cassini will have a front row seat as the gas giant´s northern hemisphere passes into spring. It will be the first time scientists observe the changing of Saturn´s seasons from such close range.
In November 2016, Cassini will begin spiraling closer and closer to Saturn´s atmosphere, passing through its rings and gathering data along the way. In April 2017, the craft will take one final cruise past Titan and just inside Saturn´s innermost ring. Cassini will then take 22 additional laps around the gas giant, getting closer and closer to its atmosphere. Finally, on September 15, 2017, Cassini is scheduled to slip into Saturn´s atmosphere where it will be crushed and vaporized by the kinetic forces at work there.
“Cassini has many more miles to go before it sleeps, and many more questions that we scientists want answered,” said Linda Spilker, a Cassini project scientist. “In fact, its last orbits may be the most thrilling of all, because we’ll be able to find out what it’s like close in to the planet, with data that cannot be gathered any other way.”
A new illustrated timeline infographic of Cassin’s 15 years of exploration is available here.
Image 2 (below): NASA’s Cassini spacecraft has been on an epic road trip, as this graphic of its orbits around the Saturn system shows. This picture traces Cassini’s orbits from Saturn orbit insertion, on June 30, 2004 PDT, through the planned end of the mission, on Sept. 15, 2017. Saturn is in the center, with the orbit of its largest moon Titan in red and the orbits of its six other inner satellites in white. Image credit: NASA/JPL-Caltech