Paul Knightly

April 8th, 2017

This illustration shows NASAs Cassini spacecraft above Saturns northern hemisphere beforeone of its 22 grand finale dives. Caption and Image Credit: NASA / JPL-Caltech

On April 26, 2017, NASAs Cassini spacecraft will conduct the first in a series of 22 dives between Saturns atmosphere and its rings as a part of the missions grand finale.

Cassinis flight team ismaking preparations to begin the spacecrafts final chapter in its 13-year history orbiting Saturn.The mission will end Sept. 15, 2017, when Cassini enters the ringed planets atmosphere, which will in turn destroy the storied vehicle, as visualized in a new video released by NASA.

An illustration of the final orbits of the Cassini spacecraft show the robotic explorer diving between the rings and the planet. The blue lines represent the 22 close flybys while the orange shows the final plunge into Saturns atmosphere. Image Credit: NASA

No spacecraft has ever gone through the unique region that well attempt to boldly cross 22 times, said Thomas Zurbuchen, the associate administrator for NASAs Science Mission Directorate, in a news release. What we learn from Cassinis daring final orbits will further our understanding of how giant planets, and planetary systems everywhere, form and evolve. This is truly discovery in action to the very end.

The dives represent the closest that Cassini has traveled to Saturn since arriving at the ringed planet in 2004. By exploring the region of space between the atmosphere and the rings, it aims to gain a new understanding into how gas giant planets and their associated ring systems form and evolve through time. The flight plan, which has been under development since a 2010 NASA decision to end the mission this year, uses expertise that has been gained over the course of the mission.

The plan to send Cassini into Saturns atmosphere was devised over concerns that once the spacecraft runs out of fuel that it could hit one of the potentially habitable moons orbiting the planet, including Enceladus.

Designing the flight plan to pass between Saturns atmosphere and rings will allow Cassini to refine its orbit over the coming months while also maximizing the scientific return of its final maneuver.

This planned conclusion for Cassinis journey was far and away the preferred choice for the missions scientists, said Linda Spilker, Cassini project scientist at NASAs Jet Propulsion Laboratory (JPL) in Pasadena, California. Cassini will make some of its most extraordinary observations at the end of its long life.

During the final months, the mission team hopes to gain insight into Saturns internal structure, the origin of its rings, obtain the first-ever sampling of the planets atmosphere and ring particles, and capture close-up views of the gas giants clouds and innermost rings.

The mission team is doing a final check of commands to be sent to the probe on April 11, which will direct Cassini to begin its final orbitsfollowing its final close pass of Titan on April 22. The gravity of Titan will bend Cassinis flight path and shrink its orbit toward Saturn with the first close flyby of the grand finale.

Based on our best models, we expect the gap to be clear of particles large enough to damage the spacecraft, said Earl Maize, Cassinis project manager at JPL. But were also being cautious by using our large antenna as a shield on the first pass, as we determine whether its safe to expose the science instruments to that environment on future passes. Certainly there are some unknowns, but thats one of the reasons were doing this kind of daring exploration at the end of the mission.

Following a distant flyby of Titan in mid-September, Cassinis flight path will be bent further to dive into Saturns atmosphere.

As Cassini enters the atmosphere, its thrusters will its the remaining fuel to keep its antenna pointed toward Earth for as long as possible, transmitting data from several instruments to provide data until the signal is lost.

Cassinis grand finale is so much more than a final plunge, said Spilker. Its a thrilling final chapter for our intrepid spacecraft, and so scientifically rich that it was the clear and obvious choice for how to end the mission.

Video courtesy of JPL

Tagged: Cassini Grand Finale Jet Propulsion Laboratory Lead Stories NASA Saturn

Paul is currently a graduate student in Space and Planetary Sciences at the University of Akransas in Fayetteville. He grew up in the Kansas City area and developed an interest in space at a young age at the start of the twin Mars Exploration Rover missions in 2003. He began his studies in aerospace engineering before switching over to geology at Wichita State University where he earned a Bachelor of Science in 2013. After working as an environmental geologist for a civil engineering firm, he began his graduate studies in 2016 and is actively working towards a PhD that will focus on the surficial processes of Mars. He also participated in a 2-week simluation at The Mars Society's Mars Desert Research Station in 2014 and remains involved in analogue mission studies today. Paul has been interested in science outreach and communication over the years which in the past included maintaining a personal blog on space exploration from high school through his undergraduate career and in recent years he has given talks at schools and other organizations over the topics of geology and space. He is excited to bring his experience as a geologist and scientist to the Spaceflight Insider team writing primarily on space science topics.

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Cassini prepares for 'grand finale' - SpaceFlight Insider