Cassini Spacecraft Celebrates a Decade of Exploring Saturn
Ten years ago today on July 1, 2004–the Cassini-Huygens spacecraft achieved a feat no other craft had done before. After completing one final burn, its main engine cut off and the craft inserted itself into orbit around the gas giant Saturn. The original mission was supposed to last four years; however, due to its success, NASA extended Cassini’s mission three times. Over the past decade, the craft has made ground-breaking scientific discoveries and sent back images of the Saturn system in unprecedented detail.
The Cassini spacecraft was composed of an orbiter (Cassini) and an European Space Agency (ESA) probe (Huygens) equipped with a total of 18 different instruments equipped for a planned 27 scientific investigations of the ringed planet and its numerous moons. Cassini’s different features give it almost human-like capabilities with perhaps the most intriguing being its antenna system. The spacecraft is able to “see” in wavelengths we cannot and can practically “feel” the magnetic fields and tiny dust particles of this massive system.
Cassini is equipped with one high-gain antenna, essential for communicating with us here on Earth and two low-gain antennas as back up in case of any power failure or other emergency. The spacecraft is very healthy and has allowed scientists to study season changes in the massive system as it completes one-third of its 30-year trip around the Sun.
Linda Spilker, a project manager at NASA’s Jet Propulsion Laboratory (JPL) commented:
“Having a healthy long-lived spacecraft at Saturn has afforded us a precious opportunity. 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.”
In 2005, the Huygens probe, named for the Dutch astronomer who first discovered Titan, has the distinction of being the first craft to land on a moon in the outer solar system. It took two hours and 27 minutes to descend to Titan’s surface and Huygens revealed that Titan’s environment was similar to Earth’s before the evolution of life — complete with methane rain and an atmosphere composed of hydrocarbons like benzene. Huygens also has the distinction of being the first to record atmospheric temperatures on Titan.
Cassini shocked scientists when it observed icy plumes on the Saturnian moon, Enceladus — so much that the mission was altered to get a better look. Upon further inspection, Cassini discovered the presence of water in these icy plumes. Life as we know it is dependent on water, so this was considered to be an important discovery. Recent data has shown evidence of a subsurface ocean on Enceladus, thus increasing its appeal and the urgency to study it in greater detail.
Over the past ten years, Cassini has spent a great deal of its time observing and studying the massive ring system around Saturn. Earlier this year, it may have spotted a new moon, dubbed “Peggy,” observed propeller-like formations and even noted the most active and potentially chaotic ring systems in our solar system — Saturn’s F-ring. Named in order of their discovery, Saturn’s rings are labeled with letters of the alphabet and starting from the closest to the planet are: D, C, B, A, F, G, and E.
With the help of Cassini and Huygens, scientists have learned more about Saturn’s largest moon, Titan, than ever before. We have discovered Saturn’s companion has many Earth-like characteristics such as rain, wind and even lakes. However, the rain on Titan is composed of methane, so you definitely would not want to be caught out in it. Titan is the most chemically complex body in our solar system outside of our own world. It’s atmosphere is a particle “zoo” containing some of the most rare and complex molecules ever discovered.
Thanks to Cassini, we have also been able to capture the first complete view of Saturn’s north pole hexagon. Saturn’s polar regions have been a scientific gold mine, surprising researchers with a long-lived massive hexagonal jet stream in the North and hurricanes at both the North and South poles. While the cause of these massive storms is still undetermined, Cassini will spend the next three years studying them in greater detail, hoping to discover their properties as well as how they formed.
Saturn Kilometric Radiation, is an emission of radio waves from the gas giant. Similar emissions were discovered coming from Jupiter and helped scientists determine Jupiter’s daily rate of rotation; however, Saturn turned out to be more complex. The rate of rotation is different in each hemisphere and also appears to vary depending on Saturn’s seasons. Currently, we do not know the length of day on Saturn.
In late 2016, Cassini will be starting its final mission , what has come to be called “The Cassini Grand Fi-nale”. During this mission, it will make a risky set of orbits, flying high above Saturn’s north pole and skimming by the narrow F-ring. It will also examine the icy plumes found on Enceladus and fly between the planet and its inner most rings a total of 22 times.
The Cassini-Huygens mission is a cooperative project between NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington.
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