Cassini at Saturn Proximal Orbits - Attitude Control Challenges

Burk, Thomas A.

doi:10.2514/6.2013-4710

Cited by 8 publications

(2 citation statements)

References 10 publications

(7 reference statements)

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“…Spacecraft pointing control will switch to RCS thrusters just prior to the Rev. 292 atmospheric transit 5 . The spacecraft will return to RWA control after the transit, and RWAs will remain in control for the remainder of the last orbit until the final plunge.…”

Section: Event Description and Key Parametersmentioning

confidence: 99%

The Last Orbit: Planning Cassini’s Plummet into Saturn

Bittner

Heventhal

Sturm

et al. 2016

SpaceOps 2016 Conference

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Cassini's final orbit around Saturn will culminate in a dramatic ending as the spacecraft plunges into the ringed planet's atmosphere, never to escape or be heard from again. The last hours of the mission prior to the final loss of signal have some of the most unique and valuable science to date. Cassini will take a unique trajectory to dive deep into the atmosphere on its approach to final disposal and no spacecraft, Cassini included, has entered these depths of Saturn's atmosphere. The science community has placed heavy emphasis on this once-in-a-lifetime opportunity to inspect these deeper regions of Saturn's atmosphere. The Cassini project specifically aims to collect the very last bits of data during the final plunge to get samples of the deepest regions before the spacecraft is lost forever. The desire to collect the final bits of data presents several challenges. Cassini's Mission Planning (MP) team has developed an End of Mission (EOM) scenario to tackle these demands. The EOM scenario outlines the framework for the entire last orbit of the mission and details the strategy for data collection and transmission. Attaining near real-time transmission is key for the acquisition of the very last bits of data. The Cassini spacecraft will use a new mode of operations to successfully achieve this real-time transmission. In addition to this primary investigation and planning for telecommunications, key risks have been studied within the realm of the last orbit. Ultimately, this paper shows how the Cassini Project plans to ensure the return of every last bit of data before the spacecraft is consumed by Saturn forever. Nomenclature MP= Mission Planning EOM = End of Mission RTG = Radioisotope Thermoelectric Generator CDS = Command and Data System SSR = Solid State Recorder DST = Deep Space Transponder TWTA = Traveling Wave Tube Amplifier AACS = Attitude and Articulation Control Subsystem RCS = Reaction Control System RWA = Reaction Wheel Assembly MEA = Main Engine Assembly SFP = System Fault Protection CDA = Cosmic Dust Analyzer CIRS = Composite Infrared Spectrometer INMS = Ion and Neutral Mass Spectrometer MAG = Magnetometer MIMI = Magnetospheric Imaging Instrument RPWS = Radio and Plasma Wave Science UVIS = Ultraviolet Imaging Spectrograph CAPS = Cassini Plasma Spectrometer 2 RADAR = Cassini Radio Detection and Ranging VIMS = Visible and Infrared Mapping Spectrometer S101 = Sequence 101 DSN = Deep Space Network OTM = Orbit Trim Maneuver Rev = Revolution LOS = Loss of Signal SCET = Spacecraft Event Time T126 = Titan Flyby 126, the last targeted Titan flyby kbps = kilobits per second DSS = Deep Space Station 70-m = 70-meter DSN antenna 34-m = 34-meter DSN antenna DOY = Day of Year SP = Science Planning UTC = Coordinated Universal Time FSDS = Flight Software Development System SCO = Spacecraft Operations

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Section: Event Description and Key Parametersmentioning

confidence: 99%

The Last Orbit: Planning Cassini’s Plummet into Saturn

Bittner

Heventhal

Sturm

et al. 2016

SpaceOps 2016 Conference

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“…However, any orbit that involves regular spacecraft crossings of the ring plane between Saturn's upper atmosphere and 2.6 Saturn radii must consider the issue of ring hazard. The design of the Cassini Grand Finale orbits was an instance where these challenges were discussed and overcome (Burk 2013;Morgan 2015). Several considerations by the attitude control team went into drafting a plan for Cassini's final orbits.…”

Section: Trajectory and Doppler Tracking Simulations For Gravity Scie...mentioning

confidence: 99%

The Case for Future Gravity Science Investigations at Saturn with a Planetary Orbiter

Parisi

2023

Planet. Sci. J.

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The next phase in the robotic exploration of the Saturnian system will target unresolved questions about the gas giant’s atmosphere, interior, magnetosphere, and rings that were left open by investigations on board the Cassini mission. Among these, we find gravity science objectives, which relate mainly to explaining the origin of the large wind-induced gravity signal and reconciling existing incongruities regarding the internal density distribution. Here we attempt to identify which future observations may yield additional information about Saturn’s internal mechanisms. We report on the results of precise numerical simulations of a gravity science experiment carried out with a planetary orbiter in the 2040s and characterized by varying periapsis altitude over the 1 bar planetary surface. The goal is to identify achievable measurement requirements that can advance the current understanding of Saturn’s interior and atmospheric dynamics. We find that inclined, elliptical orbits with low-altitude closest approaches over the northern hemisphere can improve the present determination of the gravity field coefficients by up to 1 order of magnitude, provided that at least a dozen pericenters are devoted to gravity science. Furthermore, if future observations are combined with the available Cassini Grand Finale data in the southern hemisphere, a significant improvement in terms of maximum measurable gravity field degree is observed.

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Estimator for Deep-Space Position and Attitude Using X-ray Pulsars

Runnels¹,

Gebre-Egziabher

2021

IEEE Trans. Aerosp. Electron. Syst.

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Cassini at Saturn Proximal Orbits - Attitude Control Challenges

Cited by 8 publications

References 10 publications

The Last Orbit: Planning Cassini’s Plummet into Saturn

The Last Orbit: Planning Cassini’s Plummet into Saturn

The Case for Future Gravity Science Investigations at Saturn with a Planetary Orbiter

Estimator for Deep-Space Position and Attitude Using X-ray Pulsars

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