*Robotic Autonomous Spacecraft Missions: Cassini Mission-To-Saturn Example DOI: http://dx.doi.org/10.5772/intechopen.82161*

After a highly successful Saturn Orbit Insertion (SOI) in June of 2004, the Huygens Probe was deployed onto the surface of Titan in January of 2005.

After a highly successful Saturn Orbit Insertion (SOI) in June 2004, the Huygens Probe was deployed onto the surface of Titan in January 2005. Cassini continued on to investigate Saturn, its rings, and satellites, in an outstanding 4-year expedition of the Saturnian system during its Prime Tour phase. At the end of the Prime mission (ending in 2008), all instruments and major spacecraft systems were verified to be healthy with a good volume of propellant remaining in the fuel tanks. Due to the great success of the Prime Tour with the vast quantity of new discoveries and overall quality of science returned by the spacecraft, NASA Headquarters allocated funding for the extension of Cassini's mission for a further 2 years, called the Equinox Mission (2008–2010).

#### **Figure 2.**

*Aerospace Engineering*

system to Saturn.

velocity; **Figure 1** [1]).

**2. Cassini mission summary**

After launch, spacecraft devices are typically deployed, its systems configured, and subsystem devices are verified to be working properly. During the mission, the propulsion system is utilized to target the spacecraft, adjusting its trajectory to meet the intended science targets. These target objectives typically consist of orbiting or flying by an object such as an asteroid, moon, or planet, or even landing the spacecraft (or its probe) on the target object. A suite of scientific instruments is typically carried onboard the spacecraft to perform many scientific tasks throughout the lifetime of the mission. For all National Aeronautics and Space Administration (NASA) spacecraft, the Deep Space Network (DSN) radio telescope array provides the method for the ground-based Spacecraft Operations Flight Support (SOFS) team of engineers to stay in contact with the spacecraft throughout its mission. "Uplinked" commands are sent to the vehicle while the spacecraft's "downlink" telemetry stream provides detailed information about its many systems, collected science data, and of what it encounters throughout its voyage. As an example, this chapter outlines the challenges faced by the Cassini/Huygens Mission-to-Saturn interplanetary spacecraft mission, the preparations that were necessary to support it, and the actual flight experiences during its 20-year journey through our solar

The Cassini-Huygens Mission-to-Saturn interplanetary spacecraft mission was the fourth spacecraft to visit the Saturnian system, but was the first spacecraft ever to be captured into orbit about Saturn. The Cassini Program was a joint mission between NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI), plus several other participants. Launched on October 15, 1997, Cassini traveled to Saturn following a 6.7-year cruise, which was supported by four Venus, Earth, and Jupiter planet "gravity-assist" flybys (an energy exchange between the planet and the spacecraft that accelerates the vehicle, changing its direction and

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**Figure 1.**

*Cassini-Huygens mission trajectory to Saturn.*

*Cassini's three tour phases (science mission overview).*

#### **Figure 4.**

*Saturn's ring structure and moon system (credit: NASA/JPL/Caltech).*

#### **Figure 5.** *Cassini's proximal orbit phase & final plunge (credit: NASA/JPL).*

A second mission extension was also granted, called the Solstice Mission (2010–2017) for a further 7 years of study (**Figures 2** and **3**). The Cassini mission ended with a final 42 orbit rotation through the outer and inner portion of the main ring system (F-Ring & D-Ring), followed by a fiery plunge into Saturn on September 15, 2017 (**Figures 4** and **5**, [2]).
