The NfoLD Webinar Series

Chirality indicators of extraterrestrial life – strengths and pitfalls

Dr. David Avnir

The Hebrew University of Jerusalem

About Dr. Avnir:  

David Avnir is at the Hebrew University of Jerusalem, where he received all his academic education, and where he held several positions, including Head of the Institute of Chemistry. His current scientific activities focus on materials chemistry, and on theoretical and experimental aspects of chirality and symmetry. Earlier major interests included fractals in chemistry, and far-from-equilibrium phenomena. He has co-authored over 400 papers, which are highly cited - 37,000 citations – with an h-index of 84. Recipient of various awards, including the Israel Chemical Society Excellence Award.



The major revolution in astronomy of recognizing the universe as teeming with exoplanets, the discovery of liquid water in solar moons and in atmospheres of exoplanets, and the continuing focus on Mars exploration, all accelerate the re-evaluation of potential biomarkers for extraterrestrial life. Based on life on planet Earth which relies heavily on chiral molecules and especially on homochiral families, the detection of molecules with these structural properties appears in all road-maps as prime indicators of extraterrestrial life. In this lecture will analyze the strengths, weaknesses and bounds of relying on chirality and on homochirality as biomarkers. Some of the main issues to be discussed include: The extent to which chirality can be expected to be a universal feature of life; evaluating whether detection of chirality is enough or do we need also to detect homochirality; evaluating how justified is it to view life on Earth as purely homochiral; analyzing the weaknesses of the left-right labeling of handedness; interpreting detected specific values of enantiomeric excess. A summary of recommendations and a brief outlook which will focus on the (amazing) excess of L-amino acids in meteorites, will close the lecture.


Past Webinars:

The Exobiology Extant Life Surveyor (EELS)

Dr. Morgan Cable

NASA Jet Propulsion Laboratory

Kalind Carpenter

NASA Jet Propulsion Laboratory

About Dr. Morgan Cable:  

Morgan L. Cable is the supervisor of the Astrobiology and Ocean Worlds Group at JPL. Her research focuses on organic and biomarker detection strategies, through both in situ and remote sensing techniques. She also serves as the Ocean Worlds Program Scientist for the Planetary Science Mission Formulation Office, and is a Co-I on Dragonfly and a Collaborator on the Mapping Imaging Spectrometer for Europa (MISE) instrument of Europa Clipper. Morgan has performed field work in extreme environments that serve as analogs for other worlds, such as the Atacama Desert in Chile, the lava fields of Iceland, and the summit of Mt. Kilimanjaro.

About Kalind Carpenter:  

Kalind Carpenter is a Robotics Engineer in the Robotic Vehicles and Manipulators group (347B). The lab he works in focuses on rapid technology development and end effectors specifically tailored to gripping and mobility. Current work includes Principal Investigator of the Exobiology Extant Life Surveyor (EELS), an adaptable mobility capability aimed to traverse through the plume vent crevasses on Enceladus to reach the ocean below the ice.


Plumbing the depths of the Enceladus, and possibly Europa, plume vents for liquid water, searching for extant life. Descending crevasses in ice sheets on Earth to discover the fate of melt water runoff and its effects for Earth science. The Exobiology Extant Life Surveyor (EELS) robotic architecture is designed to carry the latest instruments into these dynamic arenas in search of biosignatures. It is adaptable to traverse ocean world-inspired terrain, fluidized media, enclosed labyrinthian environments and liquids. It is a snake-like, self-propelled endoscope form comprising serially-replicated segments with encapsulated locomotion and bending. Multiple segments sequentially reverse rotations to reduce torsion in the endoscope, or replicate rotations to perform holonomic movements for steering. We will produce first-of-its-kind compliant Archimedes screw propulsion units that act as wheels, tracks, gripping mechanisms, and propelling units under water working as propellers. With EELS we may finally address the civilization-level science question in our own cosmic backyard: Are we alone?

Next generation instruments for astrobiology exploration

Dr. Pablo Sobron

SETI Institute

About Dr. Sobron:  

Pablo Sobron develops sensing technologies in robotic Earth and planetary exploration that include Curiosity, Perseverance, and Rosalind Franklin rover missions.  Find out more about some of his most recent work by visiting and Pablo founded Impossible Sensing in 2016 to promote technology transfer activities among NASA, other federal departments/agencies, research institutions, and industry at all technology readiness levels.


In this talk, Pablo will review his team's latest technology advances in planetary exploration. These technologies bring unprecedented scientific capabilities to astrobiology missions on- and off-Earth by combining innovative optoelectronics and deep data analytics. 

Is this the vent-site you should be looking for? 

Earthly prejudices

Dr. Chris German

Woods Hole
Oceanographic Institution

About Dr. German:  

Chris German is a geochemist who has served as Senior Scientist and former Chief Scientist of the National Deep Submergence Facility at the Woods Hole Oceanographic Institution. To learn about his work on ocean worlds visit


Earth’s ocean is but one of many. With the ongoing discovery and exploration of multiple ocean worlds in our solar system (e.g. Enceladus, Europa, Titan), Earth is no longer the lone field site informing our understanding of fundamental ocean processes. And yet, the diversity of submarine venting on Earth does provide valuable analog insights on what could be occurring on the floor of alien oceans. In this talk, Dr. German will guide us through a visual tour of the geo-diversity of submarine venting on Earth and describe what
they can reveal about putative venting on ocean worlds.  

Microscopes for Life Detection and Exploration: From Oceans to Space

Dr. Andrew Mullen

NASA Postdoctoral Fellow, Georgia Institute of Technology

About Dr. Mullen:  
Andrew Mullen is a Postdoctoral Fellow at Georgia Tech working with Dr. Britney Schmidt. His research there has focused on developing a submersible Digital Holographic Microscope to operate aboard the underwater robot Icefin. He has additionally conducted two field research trips to Antarctica deploying Icefin and is part of a team developing a concept instrument payload for the VERNE Europa penetrator mission study. Prior to his current position, Andrew received a PhD in Electrical Engineering from the University of California, San Diego and an MS in Oceanography from Scripps Institution of Oceanography. There, he designed a diver operated microscopic imaging system to study coral reefs. Andrew is broadly interested in the development and application of technology for earth and space exploration.


A microscope for life detection is a top candidate instrument for ocean world and other planetary missions. Microscopes developed for ocean, earth, and space exploration have significant overlap; with analog terrestrial environments offering excellent settings to test techniques for potential space application. 


In this talk, I will introduce the fundamentals of microscopic imaging and discuss the application of microscopes for life detection and environmental exploration. First, the basic principles of optical microscopy will be introduced, as well as a variety of enhanced imaging modalities. Next, I will discuss the history of microscopes used in space exploration and ongoing work developing microscopes for biosignature detection. Finally, I will present several different microscopic imaging systems designed for analog planetary missions and oceanographic exploration. This will include details on a submersible digital holographic microscope (DHM) being developed in collaboration with JPL for the underwater robot Icefin. I will also show results from a benthic underwater microscope used to observe seafloor organisms, and towed systems for imaging plankton.

By the end of this talk, I hope that you will have a better understanding of the diverse applications of microscopes, complementary research in space and ocean science, and the future potential of microscopes for biosignature detection.

In Situ Biosignature Searches with Raman and Fluorescence Spectroscopy: 
Challenges and Recommendations for Perseverance Rover

Dr. Svetlana Shkolyar

NASA Postdoctoral Fellow, Universities Space Research Association 

Research Scientist, Blue Marble Space Institute for Science

About Dr. Shkolyar:  
Svetlana's research interest involves life detection techniques and biosignature protocols on rocky and icy planetary surfaces using multiwavelength Raman and fluorescence spectroscopy. This has included studies involving false biosignature mimickers, spectral signatures of biogenic vs. abiogenic macromolecular carbon, protocols to help the Mars Sample Return campaign, and instrument development studies to inform missions to astrobiologically relevant targets in the solar system such as Europa and Mars. This also involves studies informing sample caching and return considerations on the Mars 2020 rover. 

Biosignature detection can come from in situ analyses of organic compounds on planetary surfaces. Raman spectroscopy (RS) and laser-induced fluorescence spectroscopy (LIFS) are two well-suited techniques for this purpose. Both are non-destructive, fast, require no sample preparation, and identify organics at ~ppb levels. NASA’s Perseverance Rover includes two first-time RS and LIFS payload mission instruments, SuperCam and SHERLOC. I will present several case studies on biosignature identification using a RS and LIFS instrument analogous to SHERLOC, a deep UV laser excitation (248.6 nm) RS-LIFS instrument. This will include examples of false-negative and false-positive biosignature detections posing challenges to successful biosignature detection. These case studies are aimed at improving the science return of SHERLOC and similar UV laser excitation RS and LIFS instruments in development for in situ identification of potential biosignatures on Mars and other solar system targets.

The Life Detection Forum Project

Dr. Tori Hoehler
NASA Ames Research Center

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This is the first in a series of webinars that will engage the life detection research and technology community in a dialog about how to standardize the way we think about biosignatures.  

The National Academies report, An Astrobiology Strategy for the Search for Life in the Universe, recommended that, “NASA should support the community in developing a comprehensive framework…to guide testing and evaluation of in situ and remote biosignatures.” The Life Detection Forum project is an effort to foster the community-level dialog needed for development of such a framework and, on that basis, build an online platform to centralize and promote the exchange of information, ideas, and dialog relating to life detection science and technology. This webinar will be the first in a series, and will introduce the idea and rationale behind the LDF project, provide an overview of topics to be covered in the remainder of the series, and discuss ways for the community to engage in this important dialog.

From systematic physiology
to universal principles of life

Dr. Chris Kempes
Sante Fe Institute (SFI)

About Dr. Chris Kempes

Dr. Kempes is a scientist working at the intersection of physics, biology, and the Earth sciences. Using mathematical and computational techniques, he studies how simple theoretical principles inform on a variety of phenomena ranging from major evolutionary life-history transitions, to the biogeography of plant traits, to the organization of bacterial communities. Chris also has a particular interest in biological architecture as a mediator between physiology and the local environment.

Abstract for the Webinar

A major challenge in astrobiology is understanding the full space of possibilities for living systems. A key step in meeting this challenge is to extract the general constraints from extant life and then to use these constraints to define the full range of possibilities. Organisms are subject to the laws of physics, so the process of evolution is constrained by these fundamental laws. Classic and recent studies of the biophysical limits facing organisms have shown how fundamental physical constraints can be used to predict broad-scale relationships between body size and organismal physiology. In this talk, I will discuss systematic scaling relationships for organisms along with the underlying physical, energetic, and physiological constraints and tradeoffs that can be inferred from these relationships. I will then show how these constraints can be relaxed to define a broad range of living possibilities.


Dr. Heather Graham
NASA Goddard Spaceflight Center

Thursday, 23 April, 10 am Pacific (17:00 UTC)

(Note: This webinar was not recorded)

Agnostic Biosignatures
for Extant Life Detection

About Dr. Heather Graham

Dr. Graham is an organic geochemist with widely varied research experience ranging from paleoecology to phytochemistry to astrobiology. She is profoundly curious about the natural world, the history of life, the vast connections between biotic and abiotic systems, and what evolution can tell use about our future.

When not in the lab,  she is equally passionate about building casual and formal educational ecosystems that foster creativity, build diversity, and inspire scientific excellence. And she's also an active science communicator with collaborations in art, theater, and digital media.

Abstract for the Webinar

Current strategies for biosignature detection rely mainly on identification of well-established and widely accepted features and signatures associated with the biologic processes of life on Earth, such as particular classes of molecules and isotopic signatures, enantiomeric excesses, and patterns within the molecular weights of fatty acids or other lipids. As we begin to explore icy moons of Jupiter and Saturn and other destinations far beyond Earth, methods that identify unknowable, unfamiliar features and chemistries that may represent processes of life as-yet unrecognized become increasingly important.  Life detection without presumption of terran characteristics presents a formidable challenge to any astrobiology strategy. How do we contend with the truly alien? “Agnostic” approaches to biosignature and life detection are designed to target generic characteristics of life that distinguish it from abiotic chemistry. These methods require us to utilize existing instrumentation in more general ways, pursue new leads, and synthesize data with probabilistic approaches, since agnostic methods may trade definitiveness for inclusivity. This talk will outline some of the approaches under investigation in the Laboratory for Agnostic Biosignatures, discuss potential paths towards “agnostification”, and address some of the methodological problems and knowledge gaps posed by the problem of considering “life as we don’t know it”.

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The Search for Chiral Asymmetry
as a Potential Biosignature in our Solar System

Dr. Danny Glavin, NASA Goddard Spaceflight Center

Tuesday, 25 February 2020

About Dr. Danny Glavin

Daniel Glavin earned a B.S. in physics from the University of California at San Diego in 1996 and a Ph.D. in earth sciences from the Scripps Institution of Oceanography in 2001 where he studied the amino acid and nucleobase composition of meteorites and exogenous delivery as a mechanism for delivering prebiotic organic compounds to the early Earth. He joined the 2002–03 Antarctic Search for Meteorites (ANSMET) team that recovered over 900 meteorites in Antarctica. In 2003, Dr. Glavin joined the NASA Goddard Space Flight Center in Greenbelt, Maryland, where he later cofounded the Astrobiology Analytical Laboratory at NASA Goddard. He was selected to be a Participating Scientist on the Mars Science Laboratory (MSL) mission in 2011 and was part of the team that discovered the first evidence of indigenous organic compounds on Mars using the Sample Analysis at Mars (SAM) instrument. He became NASA Goddard’s Associate Director for Strategic Science in the Solar System Exploration Division in 2014. Dr. Glavin is a Co-Investigator on the OSIRIS-REx asteroid sample return mission. In recognition of Dr. Glavin’s meteorite research, the International Astronomical Union named an asteroid after him, asteroid (24480) Glavin. He has received numerous awards including the 2007 NASA Goddard Internal Research and Development Innovator of the Year Award, the 2010 Nier Prize from the Meteoritical Society, and the 2014 NASA Robert H. Goddard Exceptional Achievement Award for Science.

Abstract for the Webinar

The search for evidence of extraterrestrial life in our Solar System is currently guided by our understanding of terrestrial biology and its associated biosignatures. The observed homochirality in all life on Earth, that is, the predominance of “left-handed” or L-amino acids and “right-handed” or D-sugars, is a unique property of life that is crucial for molecular recognition, enzymatic function, information storage and structure and is thought to be a prerequisite for the origin or early evolution of life. Therefore, the detection of L- or D-enantiomeric excesses of chiral amino acids and sugars could be a powerful indicator for extant or extinct life on another world.  However, studies of primitive meteorites have revealed they contain extraterrestrial amino acids and sugar acids with large enantiomeric excesses of the same chirality as terrestrial biology resulting from non-biological processes, complicating the use of chiral asymmetry by itself as a definitive biosignature. Here we review our current knowledge of the distributions and enantiomeric and isotopic compositions of amino acids and polyols found in meteorites compared to terrestrial biology and propose a set of criteria for future life detection missions that should be used to help establish the origin of chiral asymmetry.  Significant advances in spaceflight-qualified sample extraction, purification, and chromatographic separation technologies coupled with high-resolution mass spectrometry are needed to make these measurements. Given the complexity and limited duration of spaceflight operations and the analytical challenges associated with in situ analyses of complex organics in extraterrestrial samples, returning samples to Earth may ultimately provide the best chance to firmly establish the origin of chiral asymmetry and other potential biosignatures in our Solar System.

See this Chemical Reviews Manuscript