Patricia M. Beauchamp

Titan tholins: simulating Titan organic chemistry in the Cassini-Huygens era.

Titan Tholins: Simulating Titan Organic Chemistry in the Cassini-Huygens Era Morgan L. Cable, Sarah M. H€orst, Robert Hodyss, Patricia M. Beauchamp, Mark A. Smith, and Peter A. Willis* NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, United States Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States Department of Chemistry, University of Arizona, Tucson, Arizona 85721, United States College of Natural Sciences and Mathematics, University of Houston, Houston, Texas 77004, United States

Pluto integrated camera spectrometer (PICS) instrument

Abstract We describe an integrated instrument that will perform the functions of three optical instruments required by a Pluto Fast Flyby mission: a near-IR spectrometer (256 spectral channels, 1300–2600 nm), a two-channel imaging camera (300–500 nm, 500–1000 nm), and a UV spectrometer (80 spectral channels, 70–150 nm). A separate port, aligned in a direction compatible with radio occultation experiments, is provided for measurement of a UV solar occultation and for spectral radiance calibration of the IR and visible subsystems. Our integrated approach minimizes mass and power use, and promotes the adoption of integrated observational sequences and power management to ensure compatible duty cycles for data acquisition, compression, and storage. From flight mission experience, we believe the integrated approach will yield substantial cost savings in design, integration, and sequence planning. The integrated payload inherently provides a cohesive mission data set, optimized for correlative analysis. A breadboard version of the instrument is currently being built and is expected to be fully functional by late summer.

Formation of a New Benzene–Ethane Co-Crystalline Structure Under Cryogenic Conditions

We report the first experimental finding of a solid molecular complex between benzene and ethane, two small apolar hydrocarbons, at atmospheric pressure and cryogenic temperatures. Considerable amounts of ethane are found to be incorporated inside the benzene lattice upon the addition of liquid ethane onto solid benzene at 90-150 K, resulting in formation of a distinctive co-crystalline structure that can be detected via micro-Raman spectroscopy. Two new features characteristic of these co-crystals are observed in the Raman spectra at 2873 and 1455 cm(-1), which are red-shifted by 12 cm(-1) from the υ1 (a1g) and υ11 (eg) stretching modes of liquid ethane, respectively. Analysis of benzene and ethane vibrational bands combined with quantum mechanical modeling of isolated molecular dimers reveal an interaction between the aromatic ring of benzene and the hydrogen atoms of ethane in a C-H···π fashion. The most favored configuration for the benzene-ethane dimer is the monodentate-contact structure, with a calculated interaction energy of 9.33 kJ/mol and an equilibrium bonding distance of 2.66 Å. These parameters are comparable to those for a T-shaped co-crystalline complex between benzene and acetylene that has been previously reported in the literature. These results are relevant for understanding the hydrocarbon cycle of Titan, where benzene and similar organics may act as potential hydrocarbon reservoirs due to this incorporation mechanism.

Experimental determination of the kinetics of formation of the benzene-ethane co-crystal and implications for Titan

Benzene is found on Titan and is a likely constituent of the putative evaporite deposits formed around the hydrocarbon lakes. We have recently demonstrated the formation of a benzene-ethane co-crystal under Titan-like surface conditions. Here we investigate the kinetics of formation of this new structure as a function of temperature. We show that the formation process would reach completion under Titan surface conditions in ~18 h and that benzene precipitates from liquid ethane as the co-crystal. This suggests that benzene-rich evaporite basins around ethane/methane lakes and seas may not contain pure crystalline benzene, but instead benzene-ethane co-crystals. This co-crystalline form of benzene with ethane represents a new class of materials for Titans surface, analogous to hydrated minerals on Earth. This new structure may also influence evaporite characteristics such as particle size, dissolution rate, and infrared spectral properties.

Implications of wind-assisted aerial navigation for Titan mission planning and science exploration

The recent Titan Saturn System Mission (TSSM) proposal incorporates a montgolfière (hot air balloon) as part of its architecture. Standard montgolfière balloons generate lift through heating of the atmospheric gases inside the envelope, and use a vent valve for altitude control. A Titan aerobot (robotic aerial vehicle) would have to use radioisotope thermoelectric generators (RTGs) for electric power, and the excess heat generated can be used to provide thermal lift for a montgolfière. A hybrid montgolfière design could have propellers mounted on the gondola to generate horizontal thrust; in spite of the unfavorable aerodynamic drag caused by the shape of the balloon, a limited amount of lateral controllability could be achieved. In planning an aerial mission at Titan, it is extremely important to assess how the moon-wide wind field can be used to extend the navigation capabilities of an aerobot and thereby enhance the scientific return of the mission. In this paper we explore what guidance, navigation and control capabilities can be achieved by a vehicle that uses the Titan wind field. The control planning approach is based on passive wind field riding. The aerobot would use vertical control to select wind layers that would lead it towards a predefined science target, adding horizontal propulsion if available. The work presented in this paper is based on aerodynamic models that characterize balloon performance at Titan, and on TitanWRF (Weather Research and Forecasting), a model that incorporates heat convection, circulation, radiation, Titan haze properties, Saturns tidal forcing, and other planetary phenomena. Our results show that a simple unpropelled montgolfière without horizontal actuation will be able to reach a broad array of science targets within the constraints of the wind field. The study also indicates that even a small amount of horizontal thrust allows the balloon to reach any area of interest on Titan, and to do so in a fraction of the time needed by the unpropelled balloon. The results show that using the Titan wind field allows an aerobot to significantly extend its scientific reach, and that a montgolfière (unpropelled or propelled) is a highly desirable architecture that can very significantly enhance the scientific return of a future Titan mission.

Kuiper Express: A Sciencecraft

The Kuiper Express is a mission to achieve the first reconnaissance of one of the primitive objects that reside in the Kuiper Belt. The objects in the Kuiper Belt are the remnants of the planetesimal swarm that formed the four giant planets of the outer Solar System. These objects, because they are far from the Sun, have not been processed by solar heating and are essentially in their primordial state. This makes them unique objects and their study will provide information on the composition of the solar nebula that cannot be extracted from a study of other objects in the Solar System. The Kuiper Express is a sciencecraft mission. A sciencecraft is an integrated unit that combines into a single system the essential elements (but no more) necessary to achieve the science objectives of the mission, including science instruments, electronics, telecommunications, power, and propulsion. The design of a sciencecraft begins with the definition of mission science objectives and cost constraint. An observational sequence and sensor subsystem are then designed. This sensor subsystem in turn becomes the design driver for the sciencecraft architecture and hardware subsystems needed to deliver the sensor to its target and return the science data to the earth. Throughout the design process, shared functionality, shared redundancy, and reduced cost are strongly emphasized. The Kuiper Express will be launched using a Delta vehicle and will use solar electric propulsion to add velocity and shape its trajectory in the inner Solar System, executing two earth gravity-assist flybys. It will also execute flybys of main belt asteroids, Mars, Uranus, and Neptune/Triton en route to its target in the Kuiper belt, where it will arrive about ten years after launch. It will use no nuclear power. The surface constituents and morphology of the objects visited will be measured and their atmospheres will be characterized. The cost of the detailed design, fabrication, and launch of the Kuiper Express is consistent with the

JPL technology readiness assessment guideline

150M limit set by the NASA Discovery Program.

Technology development for NASA science missions: Challenges and potential opportunities

New capabilities in spaceflight missions are enabled by new technologies. Transitioning new technology to spaceflight elements is difficult and introduces risk, but finding the right balance between benefit and risk leads to scientific advancements and novel space missions. A clear understanding of the risks of new technology can create an environment where innovation is nurtured rather than avoided. The Technology Readiness Level (TRL) was developed as a metric for the maturity of new technology, but, in the past, assessing the TRL was often done informally and inconsistently. This frequently led to discrepancies between the TRL as perceived by the technologist and that perceived by a project. JPL has developed a guideline for their projects to provide a basis for a consistent Technology Readiness Assessment (TRA). Highlights of this guideline are presented here. It is anticipated that the implementation of this guideline will enable the hand-off from technologists to project engineers leading to greater acceptance of technologies by flight projects. On completion of a satisfactory TRA, an agreement can be made between the parties on the maturation plan required for successful infusion of the technology into a flight mission.

Atmospheric Planetary Probes and Balloons in the Solar System

NASA has made tremendous progress in addressing critical questions about our solar system but often the knowledge gained raises new and more challenging questions. Future robotic space missions need to be endowed with more capable instruments, spacecraft subsystems and ground support to answer the new and more difficult questions that lay before us. Developing future instrument, spacecraft subsystem, or ground support technologies for robotic planetary missions is a complicated and challenging endeavor. Recognizing this, the Planetary Science Division (PSD) in NASAs Science Mission Directorate recently chartered a panel to review its current technology development programs and provide recommendations on process and policy improvements that will enable better utilization of technology resources. This paper discusses the work and findings of that panel, known as the Planetary Science Technology Review (PSTR) panel.

NEPTUNE: An under-sea plate scale observatory

A primary motivation for in situ probe and balloon missions in the solar system is to progressively constrain models of its origin and evolution. Specifically, understanding the origin and evolution of multiple planetary atmospheres within our solar system would provide a basis for comparative studies that lead to a better understanding of the origin and evolution of our own solar system as well as extra-solar planetary systems. Hereafter, the authors discuss in situ exploration science drivers, mission architectures, and technologies associated with probes at Venus, the giant planets and Titan.