June 30, 2014
Cassini-Huygens Mission Marks 10 Years Of Studying Saturn Today
redOrbit Staff & Wire Reports - Your Universe Online
[ Watch the Video: Cassini Saturn Arrival ]
Cassini reached its destination on June 30, 2004, carrying with it the European Space Agency's Huygens probe. Over the past 10 years, it has completed 206 orbits, discovered seven new moons, and captured in excess of 330,000 images.
“Having a healthy, long-lived spacecraft at Saturn has afforded us a precious opportunity,” Cassini project scientist Linda Spilker said in a statement Wednesday. “By having a decade there with Cassini, we have been privileged to witness never-before-seen events that are changing our understanding of how planetary systems form and what conditions might lead to habitats for life.”
Given the years of service both Cassini and Huygens have provided astronomers over the years, it should come as no surprise that the spacecraft and the probe are responsible for some noteworthy accomplishments. While Spilker explained that it was “incredibly difficult to sum up 10 extraordinary years of discovery,” that didn’t prevent NASA from compiling a list of the 10 most important discoveries made by Cassini-Huygens during its decade at Saturn.
One of those moments came in 2005, when Huygens landed on Saturn’s moon Titan, becoming the first probe to touch-down on a moon in the outer solar system. During its nearly 2 1/2 hour descent, it revealed that Titan was remarkably similar to Earth before the evolution of life, the space agency explained. The probe found benzene and other complex hydrocarbons there, and provided the first on-site measurements of the atmospheric temperature.
Eventually, imaging with radar and both visible and infrared wavelengths revealed that Titan possessed many geological processes similar to those of our home planet, and that it was home to some of the most chemically complex molecules in the entire solar system. The smog that covers the massive moon was formed with large molecules, while methane, ethane and other organic substances could be found closer to the surface.
Cassini also discovered active, icy plumes on another one of Saturn’s moons, Enceladus. According to NASA, the discovery was so surprising that “mission designers completely reshaped the mission to get a better look. The discovery became even more important when Cassini found evidence of water-based ice in the plume. Life as we know it relies on water, so the search for life suddenly extended to this small, bright moon.” The agency went on to call Enceladus “one of the most exciting science destinations in our solar system.”
Saturn’s rings turned out to be the source of a few of the Cassini mission’s greatest discoveries as well. The length of the spacecraft’s mission made it possible to watch changes in the planet’s dynamic ring system, revealing propeller-like formations and even witnessing the possible birth of a new moon, according to NASA. The vertical structures in the rings were also imaged for the first time, thanks to Cassini, which determined their height by measuring shadows resulting from a rare instance of sunshine on the edge of the ring plane on the northern and southern sides.
Cassini also managed to study the great northern storm of 2010 and 2011, which resulted in the largest temperature increase ever recorded for any planet, and discovered giant hurricane-like storms at both of Saturn’s poles. In addition, it also solved the 300-year-old mystery of the dual bright-dark surface of Iapetus, discovering that dark, reddish dust in the moon’s orbital path is swept up, lading on its leading face. The dark areas absorb energy and become warmer, while uncontaminated areas remain cooler.
While the mission was originally approved for just a four-year period, Cassini’s engineers and scientists had hopes that it would live on past that so-called expiration date and made sure to design it for endurance. NASA said that the mission has been “remarkably trouble-free” and that its future basically depends on how much propellant remains in its tanks – a testament to the longevity of the mission, and the talents of its navigation and operations teams.
“Our team has done a fantastic job optimizing trajectories to save propellant, and we've learned to operate the spacecraft to get the most out of it that we possibly can,” said Earl Maize, Cassini project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “We're proud to celebrate a decade of exploring Saturn, and we look forward to many discoveries still to come.”