Dataset Features Established

Almost 13 years spent by Cassini mission in the orbit of Saturn were the headmost chance to study this anonymous planet charm, which seduces you for a closer look to it, throughout the spacecraft's passing near Saturn, by this stage within the approach gradation, the planet Saturn was huge quite, so that dual narrow-angle camera was needed to cover the whole size of Saturn with its rings and some of its icy moons. Figure 1 shows the movement of the satellite, it was evaluated by mapping samples to the image edge to the spacecraft target. Moving at velocity with respect to Sun approaching 137,000 km/h, the spacecraft has traveled almost 362,000,000 km during its whole mission. During its mission Cassini has gathered samples and sending them back to Earth, returned samples confer experts to exploits up-to-date technologies to enlarge the scientific value.

Figure 1. Movement of Cassini-Huygens spacecraft. a) The motion of the spacecraft, while the engine is turned off, was dominated by gravity along with the momentum; b) Histogram shows the relationship between intensity of Cassini movement among sampling, measuring the spacecraft movement give the opportunity for researchers to trace Saturn gravitational

field

With the gravity assistance of the planets of the Earth, Jupiter and Venus it required Cassini 6.7 years to reach Saturn, the following Figure 2 shows the mission phases magnitude correlated with samples, the IDs for the phases have been extracted from the metadata mission file, and it includes 14 phases.

Figure 3 depicts Cassini mission phases and the relative trajectory of Cassini to Sun, the mission is destined to explore the planet Saturn with its amazing rings and its various moons with distinctive and close attention on Titan.

Different shapes were allotted to show the correlation between the phases and their IDs. Subsequent to the launch which happened on 15 October 1997, a flyby period Cassini orbiter has spent near to three planets before arriving to Saturn system on 1 July 2004. When the nominal mission has accomplished by the date of July 2008, the orbiter had finished 75 orbits on its journey around Saturn. Primarily the mission was timetabled for a 4 years period that extends from 2004 till 2008, which is known as (primary mission), Since the mission was quite felicitous, so it was protracted twice, the first extension for the expedition took place in July 2008 and proceeded till October 2010, it is known as Equinox mission. The main purpose of this extension was to monitor the system of the planet Saturn during the time that the Sun passes the equatorial plane of Saturn. The next and final extension termed as Solstice mission and had lasted until 2017, with a crucial intent to observe the seasonal variations resulted from mutating solar illumination, up to the Sun amounts to its greatest vertical extent elevation on/at the top of Saturn's equatorial plane.

The generated graphic of the Figure 4(a) characterizes Cassini's flight mission path around the sun on its total mission length, which has started on 15 October 1997, and ended on September 15, 2017, while the insertion to Saturn orbit has happened on 1 Jul 2004.

Figure 2. Phases of the interplanetary mission Cassini-Huygens. 10% of the mission time: 14 phases, 90% of the total time: just 3 phases. phase 5 contains just two samplings

(31641…31644) making it invisible in the current scale of representation

Figure 3. Trajectory of the mission phases. a) First 35,000 of samples, it is found that the samples can be classified into groups based on the phase names of the mission. b) Samples

starting with 35,001 till 407,304

Figure 4. Trajectory parameters of the spacecraft Cassini-Huygens. a) The start of the path in the first graphic is pointed with the shape of a circle, while the end of the path is pointed with the shape of small square. b) The generated graphics represent the distance measured in KM between the sun and Cassini spacecraft during the whole mission when the

mission finished, Cassini spacecraft had crossed a distance of (7.8 billion kilometers) with regard to the Sun. The relationship among the independent variable sampling number and the dependent variable distance(D) is modeled as the 5th degree polynomial in sampling

number, fit function returns the coefficients for a polynomial p(sample#) with the degree 5 (to fit a polynomial to data of degree 5), which is considered the optimal fit (among the least square error R2 estimate). The polynomial coefficients have an inclined descendant of

powers p(D)=p₁D_n + p₂D_n-1 + .... + p_nD_n+1

During this journey, the spacecraft used the gravity-support flybys of various plants (Earth, Jupiter, Venus) with the purpose of boosting the velocity of the spacecraft proportionally to the sun in order to arrive at Saturn planet. Regarding the graphic in the Figure 5 concerning the position and velocity, it is known now from a scientific point of view that scientists might measure a car speed corresponding to the street that it uses. On the other hand, measuring the speed of a spacecraft is more complicated as it requires dual measurements proportional to the land and air in which it flies over and through respectively.

The velocity can be defined as a vector, thus the variation could be in the magnitude in addition to direction if that change is characterized by the feature of positivity, then the space shuttle is accelerated, while if it is characterized as negative then there is a reduction in the speed, it relies on the route that the spacecraft is taking, if the spacecraft in the forepart of the luminary, the spacecraft will waste speed, while if its position is behind the luminary, then it earns speed. It is known that any spacecraft that travels in the deep space, can be in contact with the planet of the Earth by dispatching radio signals, these signals could provide us with the spacecraft velocity by two methods.

The first method is straightforward, as the signals move the same speed of the light, then we could specify how much is the distance between this object and the Earth by the time period it takes for the radio signal to reach to it, rebound and march back, if the signal requires a greater period today than it took yesterday.

Then we can specify how much the spacecraft has moved in a single day also we can conclude the velocity, a further precise method of informing spacecraft velocity is via utilizing the Doppler effect, which is exploiting information concerning frequency shift of electromagnetic signals generated by moving spacecraft, based on that we could deduce the velocity.

In view of the fact that Cassini exploits the moon (Titan) gravity as hub spot for its considerable trajectory changes. Only one adjacent flyby of Titan will supply Cassini with a velocity change nearly could almost reach the propellant power that Cassini had at the phase of launching, so if Cassini pass by Titan with an inaccurate speed, then Cassini may end up moving in an incorrect way, consequently the navigation team back on Earth is in charge of taking such decisions regarding relative speeds to make sure that such errors doesn’t occur. Cassini would burn a little fuel to adjust the mistake. Normally, Cassini exploits propellant just to perform some slight rectifications to get back to the correct trajectory, the off-target is estimated by one kilometer. But if it fails to hit the target by tens of miles, current trajectory must have to be rescheduled or deleted; as resetting the trajectory may need another 6 months.

In Figure 6, we plotted the velocity of the Cassini spacecraft to Sun, as each object’s velocity should be designated with respect to other objects, the velocity is specified in kilometers per second, Cassini's velocity changed from 18.85 kilometers per second at the beginning of the maneuver to 18.4 kilometers per second at the terminus of the engine firing. The velocity was approaching 450 meters per second

Figure 5. Position and velocity of Cassini with respect to the Sun. a) Time dependence of the spacecraft Ox, Oy, Oz coordinates; b) Superposition of the velocity components of the

Cassini

Figure 6. Velocity behavior of the Cassini spacecraft. a) Time dependence of the spacecraft Vx, Vy, Vz velocity components; b) Absolute value of the Cassini velocity vs. time in December 1998, then it was almost stationary to 4.851 kilometers per second.

The thought with showing up Cassini’s movements toward targets was to form a cumulative voyage as it made its paths over the solar system. Also, to demonstrate the movement to the target with respect to different axes point of view (X, Y, Z).

5. Conclusions

GIS can expand remarkably the scope of analysis which could be accomplished by planetary specialists; as GIS put forward the appropriateness to integrate various patterns of data into distinct categories of information also to perform the required analyzation via several approaches, as well as analysis techniques can reduce the spatial ambiguity and associated challenges regarding the diverge of terrestrial references. The sampled values in scale of Big Data of the Cassini-Huygens planetary project has been analyzed to make more clear orientation on the mission phases. The current framework will be continued to identify special events of the whole project finished after more than thirteen years of collecting interspatial data.

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