PSAS: X-Ray Diffraction (XRD) for the Analysis of Materials


XRD is a powerful technique to perform qualitative and quantitative analyses of materials and is most widely used for the identification of unknown crystalline materials. Determination of unknown solids is critical to studies in geology, environmental science, and material science to name but a few. When X-Rays contact a crystal, a series of reflections are produced that are unique and characteristic for each phase, similar to a fingerprint. It is a method that does not require large amounts of material, even very small amounts of material can be measured with special holders, and is non-destructive. This presentation will be focused on how XRD is used to measure materials from domestic and extraterrestrial sources.



CSTAR Distinguished Lecture

Dragonfly: In Situ Exploration of Titan’s Organic Chemistry and Habitability

Dr. Elizabeth Turtle, PI of Dragonfly Mission

Thursday, November 19, 6:30 pm


Saturn’s largest moon, Titan, is an Ocean World with a dense atmosphere, abundant complex organic material on its icy surface, and a liquid-water ocean in its interior. The joint NASA-ESA Cassini-Huygens mission revealed Titan to be surprisingly Earth-like, with active geological processes and opportunities for organic material to have mixed with liquid water on the surface in the past. These attributes make Titan a singular destination to seek answers to fundamental questions about what makes a planet or moon habitable and about the pre-biotic chemical processes that led to the development of life here on Earth.
NASA’s Dragonfly New Frontiers mission is a rotorcraft lander designed to perform wide-ranging in situ investigation of the chemistry and habitability of this fascinating extraterrestrial environment. Taking advantage of Titan’s dense atmosphere and low gravity, Dragonfly can fly from place to place, exploring diverse geological settings to measure the compositions of surface materials and observe Titan’s geology and meteorology. Dragonfly will make multidisciplinary science measurements at dozens of sites, traveling ~150 km during a 3-year mission to characterize Titan’s habitability and determine how far organic chemistry has progressed in environments that provide key ingredients for life.
Speaker bio: Dr. Elizabeth (Zibi) Turtle is a planetary scientist at the Johns Hopkins Applied Physics Laboratory. Her research combines remote-sensing observations and numerical geophysical models to study geological structures and their implications for planetary surfaces, interiors, and evolution, including tectonics and impact cratering on terrestrial planets and outer planet satellites, the thickness of Europa’s ice shell, Ionian mountain formation, and Titan’s lakes and weather. She is the Principal Investigator for the Dragonfly New Frontiers mission to Titan and the Europa Imaging System (EIS) cameras on the Europa Clipper mission, and has participated in the Galileo, Cassini, and Lunar Reconnaissance Orbiter missions. She earned her Ph.D. in Planetary Sciences from Univ. Arizona and B.S. in Physics from MIT.

PSAS: Space Weather: The Science, its Effects and Mitigation


Solar flares can produce x-rays that affect satellite communication in the near-Earth environment, it can degrade or block communication signals.  Solar energetic particles can penetrate satellite electronics and cause electrical failure.   Coronal Mass Ejections (CME’s) can cause Geomagnetic Storms at Earth and induce extra currents at the ground that can degrade power grids and other infrastructure. All these events are termed space weather and need to be studied, forecasted, and notified in advance to mitigate its effects.  In this seminar, we will talk about space weather, its effect, and forecasting capabilities to mitigate its effects. 

PSAS: Enceladus Orbilander: Designing Flagship-class Mission Concepts for the Next Decadal Survey

Cassini revealed Saturn’s moon Enceladus as the host of a subsurface ocean where the key factors of habitability appear to be collocated. A return mission is needed to determine if that habitability potential supports life, but how should such a search for life be conducted? What biosignatures might we target? What geochemical and geophysical investigations would provide the context most useful for interpreting biosignature searches? In preparation for the 2023-2032 Decadal Survey, we explored what Flagship-class (>$2B) missions answering these questions might look like. In this talk, I’ll describe how we defined the driving science goals and objectives, selected a representative payload, and evaluated the science value of different architectures. I’ll then present the result of our study, Orbilander, a mission concept where a single spacecraft first orbited and then landed, and why it represents a compelling option for returning to Enceladus to search for life.

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PSAS: Lunar Flashlight

Lunar Flashlight is an innovative, small NASA mission to be launched as a secondary payload on the first Space Launch System, Artemis-1. This highly mass- and volume-constrained satellite will demonstrate several technologies for NASA, including the use of “green” propellant, the ability for a CubeSat-sized satellite to perform science measurements beyond low Earth orbit, and the first planetary mission to use multi-band active reflectometry from orbit. Lunar Flashlight will detect and map water ice in permanently shadowed regions of the lunar south pole by measuring surface reflectance at multiple wavelengths. Mapping and quantifying lunar water ice addresses one of NASA’s Strategic Knowledge Gaps to understand the lunar resource potential for future human exploration of the Moon.

PSAS: How inappropriate to call this Planet Earth


Brief summary: The very first “ocean life detection” mission took place on board the HMS Challenger in 1872, as it set out to establish the existence of life at the deepest ocean depths. Scientists and crew sailed for four years collecting chemical, geological and biological samples from the far reaches of our world, and produced to first comprehensive survey of Earth’s ocean – from sea surface to sea floor. Today, scientists explore the ocean through a combination of human-operated and autonomous instruments. The technological landscape is changing at an unprecedented rate. Space scientists are also rapidly developing technologies required for missions to other worlds, including ocean worlds, despite the striking difference in the resources invested in ocean versus space science instrumentation. Our laboratory focuses on better understanding how matter/enery flow between the biosphere and the lithosphere. To that end, we develop technologies that help further our understand of these relationships, both in the ocean and on land.

We are, however, also committed to democratizing science by developing modular, open-design vehicle and sensor platforms that allow inexpensive commercial sensors (as well more bespoke emerging technologies) to be easily deployed on deep-sea missions. Here I will present some of the latest developments -as well as the lessons- from exploring our own inner space. We will also present our data from recent efforts aimed at examining the relationships among abiotic and biological processes in our ocean. These technologies and methods can help us unlock the mysteries of the cosmos, in particular that enduring question of whether life exists on other celestial bodies. We posit that fostering a rich and extensive collaboration among ocean and space scientists is critical if we are to advance our understanding of other ocean worlds, such as Enceladus and Europa, beyond the scope of current missions and technologies.”

PSAS: Predicting Europa and Enceladus seawater chemistry using volatile CO2 measurements


The Europa Clipper mission will be able to measure volatile CO2 isotopes of Europa’s plumes and exosphere—but what can those measurements tell us about the surface ice or subsurface ocean? Our laboratory experiments interact an initial gaseous CO2 (that may be sourced from water-rock interactions at the seafloor) with various seawaters, and measure the resulting CO2 to determine what changes take place as a result of this interaction. Isotopes of CO2 from low pH systems do not show a substantial change for carbon, suggesting that carbon isotopes from a low pH Europa will reflect the original CO2.
However, alkaline (high pH) systems similar to Enceladus or a high-pH Europa show a large variability in carbon isotopes that is due to varying carbonate speciation. We use our laboratory spectra as a ‘training’ dataset for machine learning. Our preliminary work demonstrates that ‘supervised’ training of metadata and data from these spectra form clusters based on the concentration of CO2 and the composition of the seawater, and is therefore promising for future interpretation of CO2 mass spectra using predictive algorithms.

Inaugural Prebiotic Chemistry and Early Earth Environments (PCE3) Community Workshop


You are invited to participate in the Inaugural Prebiotic Chemistry and Early Earth Environments (PCE3) Community Workshop, which is intended to form bridges between disparate fields of astrobiology. 

Registration is free and required to attend. You will receive an email with log-in after being approved. There is no cost to register. Register here: 

The workshop is designed to cross-pollinate between different areas of research addressing origins of life, including early earth geoscience and prebiotic chemistry. This workshop will foster intellectual cooperation and innovation across the community and thereby give rise to novel research avenues. A central goal is to root models for the emergence of prebiotic pathways in realistic planetary conditions and fully integrate the dynamics and constraints of early Earth environments into origins hypotheses. Beyond our planet, PCE3 aims to identify planetary conditions that can or cannot give rise to life’s chemistry, thus guiding future missions that target the discovery of habitable worlds.

Workshop speakers have been asked to give a state-of-the-art talk in their respective sub-theme to *other* fields of the Origins of Life community. These talks will be accessible to a non-specialist and aim to highlight the points of agreement, the important remaining debates, uncertainties, and essential next steps. The presentations are meant to be “neutral” in that they don’t advocate for any specific model, but instead cover the range of scientific opinions. The talks will explain explicitly how these interdisciplinary themes are relevant and important to the Origin of Life community. The foundational information presented in this workshop will enable future workshops and collaborations that bridge the many disciplines that are part of PCE3.
Each of five interdisciplinary themes will be the focus of one week of the workshop:
1. Earliest Planetary Formation
The primer talks will be posted on Monday, October 5.
    *   Stellar Evolution (Edward Schwieterman)
    *   Accretionary History & Planetary Dynamics (Rebecca Fisher)
    *   Origin of the Moon (Miki Nakajima)
    *   Hadean Geodynamics (Rick Carlson)
    *   Impact History (Simone Marchi)
The discussion meeting on this topic will be on Friday, October 9, at 1pm Eastern Daylight Time.
2. Evolution of the Near Surface
The primer talks will be posted on Monday, October 12.
    *   Chemical Crustal Evolution & Oldest Crust (Ann Bauer)
    *   Physical Crustal Evolution (Brad Foley)
    *   Atmosphere and Ocean Evolution (Kevin Zahnle)
    *   Lithospheric Fluid Composition (Everett Shock)
The discussion meeting on this topic will be on Friday, October 16, at 1pm Eastern Daylight Time.
3. Inventories, Geological Settings, and Building Blocks
The primer talks will be posted on Monday, October 19.
    *   Geological Settings and Local Conditions (Martin van Kronendonk)
    *   Meteoritic/Exogenous Delivery (Zita Martins)
    *   Haze and Atmospheric Synthesis (David Catling)
    *   Surface Chemistry and Abiotic Organic Synthesis (Benedicte Menez)
The discussion meeting on this topic will be on Friday, October 23, at 1pm Eastern Daylight Time.
4. Prebiotic Complexity
The primer talks will be posted on Monday, November 9.
    *   Overview (David Deamer)
    *   Formation of Precursors, Simple Molecules, Selection I (James Cleaves)
    *   Formation of Precursors, Simple Molecules, Selection II (Laurie Barge)
    *   Processes Acting on Building Blocks, Assembly and Complexification I (Luke Leman)
    *   Processes Acting on Building Blocks, Assembly and Complexification II (Christine Keating)
The discussion meeting on this topic will be on Friday, November 13, at 1pm Eastern Daylight Time.
 5. Peering into the Past with Today’s Biochemistry
The primer talks will be posted on Monday, November 16.
    *   Overview – Biochemistry meets Prebiotic Chemistry (Ram Krishnamurthy)
    *   Genetics (Hannes Mutschler)
    *   Metabolism (George Cody)
    *   Chemical Evolution (Moran Pinter-Frenkel).
    *   Earliest Evidence of Life (Elizabeth Bell)
    *   Rewinding Life’s Clock (Greg Fournier)
The discussion meeting on this topic will be on Friday, November 20, at 1pm Eastern Daylight Time.
Questions? Please email workshop organizer Loren Williams.