Titan Explorer: A NASA Flagship Mission Concept

Lorenz, Ralph D.; Leary, James C.; Lockwood, Mary Kae; Waite, J. H.

doi:10.1063/1.2844991

Cited by 12 publications

(9 citation statements)

References 1 publication

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“…Coustenis et al 2009;Tobie et al 2014). A Titan orbiter equipped with a thermal infrared spectrometer (as in the 2007 Titan Explorer mission concept, Lorenz & Waite 2008) and other instruments would permit frequent global 'snapshot' measurements of the entire atmospheric state, including temperature, winds and composition. These, in turn, would enable much tighter constraints to be placed on atmospheric models, such as coupled chemistry and climate 3-D Titan GCMs now under development (Lebonnois et al 2009(Lebonnois et al , 2012.…”

Section: Discussionmentioning

confidence: 99%

Cassini Composite Infrared Spectrometer (CIRS) Observations of Titan 2004–2017

Nixon

Ansty

Lombardo

et al. 2019

ApJS

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From 2004 to 2017, the Cassini spacecraft orbited Saturn, completing 127 close flybys of its largest moon, Titan. Cassini's Composite Infrared Spectrometer (CIRS), one of 12 instruments carried on board, profiled Titan in the thermal infrared (7-1000 µm) throughout the entire 13-year mission. CIRS observed on both targeted encounters (flybys) and more distant opportunities, collecting 8.4 million spectra from 837 individual Titan observations over 3633 hours. Observations of multiple types were made throughout the mission, building up a vast mosaic picture of Titan's atmospheric state across spatial and temporal domains. This paper provides a guide to these observations, describing each type and chronicling its occurrences and global-seasonal coverage. The purpose is to provide a resource for future users of the CIRS data set, as well as those seeking to put existing CIRS publications into the overall context of the mission, and to facilitate future inter-comparison of CIRS results with those of other Cassini instruments, and ground-based observations.

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Section: Discussionmentioning

confidence: 99%

Cassini Composite Infrared Spectrometer (CIRS) Observations of Titan 2004–2017

Nixon

Ansty

Lombardo

et al. 2019

ApJS

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“…3. We note that similar studies for identification of organic compounds from orbit have been conducted for the 5.0 -6.0 µm region Lorenz et al (2008), the 2.6 -2.8 µm and 5.0 -5.2 µm windows accessible to VIMS (Clark et al, 2010), but we expand on these here considerably by considering all windows between 0.4 µm -10 µm, the ability to detect at several mission architecture altitudes, and a wider range of compounds. For the alkanes Fig.…”

Section: Ability To Detect Surface Compoundsmentioning

confidence: 81%

Modeling transmission windows in Titan’s lower troposphere: Implications for infrared spectrometers aboard future aerial and surface missions

Corlies

McDonald

Hayes

et al. 2021

Icarus

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From orbit, the visibility of Titan's surface is limited to a handful of narrow spectral windows in the near-infrared (near-IR), primarily from the absorption of methane gas. This has limited the ability to identify specific compounds on the surface-to date Titan's bulk surface composition remains unknown. Further, understanding of the surface composition would provide insight into geologic processes, photochemical production and evolution, and the biological potential of Titan's surface. One approach to obtain wider spectral coverage with which to

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“…The Lockwood report in turn became a significant input to a Titan 'flagship' (i.e. large-size) mission study commissioned by NASA and led by the Johns Hopkins University Applied Physics Laboratory [6], which emphasized aerocapture as a preferable option to chemical propulsion for enhancing delivered mass into Titan orbit.…”

Section: Introductionmentioning

confidence: 99%

Aerocapture design study for a Titan polar orbiter

Nixon

Kirchman

Esper

et al. 2016

2016 IEEE Aerospace Conference

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In 2014 a team at NASA Goddard Space Flight Center (GSFC) studied the feasibility of using active aerocapture to reduce the chemical ΔV requirements for inserting a small scientific satellite into Titan polar orbit. The scientific goals of the mission would be multi-spectral imaging and active radar mapping of Titan's surface and subsurface. The study objectives were to: (i) identify and select from launch window opportunities and refine the trajectory to Titan; (ii) study the aerocapture flight path and refine the entry corridor; (iii) design a carrier spacecraft and systems architecture; (iv) develop a scientific and engineering plan for the orbital portion of the mission. Study results include: (i) a launch in October 2021 on an Atlas V vehicle, using gravity assists from Earth and Venus to arrive at Titan in January 2031; (ii) initial aerocapture via an 8-km wide entry corridor to reach an initial 350×6000 km orbit, followed by aerobraking to reach a 350×1500 km orbit, and a periapse raise maneuver to reach a final 1500 km circular orbit; (iii) a three-part spacecraft system consisting of a cruise stage, radiator module, and orbiter inside a heat shield; (iv) a 22-month mission including station keeping to prevent orbital decay due to Saturn perturbations, with 240 Gb of compressed data returned. High-level issues identified include: (i) downlink capability-realistic downlink rates preclude the desired multispectral, global coverage of Titan's surface; (ii) power-demise of the NASA ASRG (Advanced Stirling Radioisotope Generator) program, and limited availability at present of MMRTGs (Multi-Mission Radioisotope Generators) needed for competed outer planet missions; (iii) thermal-external radiators must be carried to remove 4 kW of waste heat from MMRTGs inside the aeroshell, requiring heat pipes that pass through the aeroshell lid, compromising shielding ability; (iv) optical navigation to reach the entry corridor; (v) the NASA requirement of continuous critical event coverage for the orbiter, especially during the peak heating of the aerocapture when the radio link will be broken. In conclusion, although Titan aerocapture allows for considerable savings in propellant mass, this comes at a cost of increased mission complexity. Further architecture study and refinement is required to reduce high-level mission risks and to elucidate the optimum architecture.

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Titan Explorer: A NASA Flagship Mission Concept

Cited by 12 publications

References 1 publication

Cassini Composite Infrared Spectrometer (CIRS) Observations of Titan 2004–2017

Cassini Composite Infrared Spectrometer (CIRS) Observations of Titan 2004–2017

Modeling transmission windows in Titan’s lower troposphere: Implications for infrared spectrometers aboard future aerial and surface missions

Aerocapture design study for a Titan polar orbiter

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