SCIENCE HIGHLIGHTS 26 March 2021 Code S Weekly Report

Key Highlights

Earth Science:

• Ryan Spackman and Florian Schwandner met with California state agencies (CNRA, CalEPA, CDFA) and JPL to explore a more coordinated science and technology response to the region’s wildfire and drought threat.

• The Western Diversity Time Series (WDTS) ER-2 flights continue out of AFRC with AVIRIS (JPL) and MASTER (ARC). The team has now completed 4 science flights as well as 1 functional check flight.

Space Science:

Planetary Science

• A dozen division scientists from SST and SSA contributed to 13 of the 24 articles in the March 1 Icarus special issue: Pluto System, Kuiper Belt, and Kuiper Belt Objects. In addition, Oliver White (SST/SETI) was on the editorial board for the issue. A full list of papers and authors is found in the publications section below. https://www.sciencedirect.com/journal/icarus/vol/356/suppl/C

Astrophysics

• Scott Sandford (S) participated in an all-day OSIRIS-REx Sample and Curation Technical Interchange Meeting held on March 19, 2021. The purpose of this meeting was to begin the detailed coordination of the tasks associated with the curation and analysis of samples to be returned from asteroid Bennu by the OSIRIS-REx spacecraft in 2023. Dr. Sandford presented material associated with the analysis of components of the Sample Return Capsule.

Astrobiology

• Melissa Kirven (SSX) participated in am Artemis Moon Pod Essay Contest event in which K-12 students asked questions which were answered by a current NASA Astronaut and NASA scientists. https://www.futureengineers.org/artemismoonpodessay

Space Biosciences:

• Twelve Biology of Spaceflight Papers Represent Groundbreaking Work Last November, a coordinated package of 29 scientific papers on the biology of spaceflight was published in five Cell Press journals and appeared online in Cell, Cell Reports, iScience, Cell Systems, and Patterns. Among the groundbreaking work published in the Cell Press package are 12 scientific papers authored by scientists in the NASA Ames Research Center Science Directorate. Coordination of the publication of these papers was led by Drs. Afshin Beheshti (NASA Ames Research Center), Susan Bailey (Colorado State University), and Christopher Mason (Weill Cornell Medicine). Over 200 news articles were published worldwide on social media, and in newspapers and science journals. Twelve plain language summaries of these articles for the science community are now available on the NASA website.

DIVISION HIGHLIGHTS IN FULL

EARTH SCIENCE DIVISION HIGHLIGHTS SG Weekly Report

Date: 24 March 2021 Division: SG

SIGNIFICANT ANNOUNCEMENTS

• Ryan Spackman and Florian Schwandner met with California state agencies (CNRA, CalEPA, CDFA) and JPL to explore a more coordinated science and technology response to the region’s wildfire threat and drought threat. Ryan Spackman presented the Earth Science Division’s core capabilities and highlighted how Ames can contribute to the urgent wildfire and drought problem..

• Diana Gentry’s proposal to the FY21 Ames Research Innovation Award (ARIA), “Constraints on Methanogenesis in a Europan Ocean Analog” was selected for funding.

• The Western Diversity Time Series (WDTS) ER-2 flights continue out of AFRC with AVIRIS (JPL) and MASTER (ARC). The WDTS studies terrestrial ecosystems and provides critical information on natural disaster such as volcanoes, wildfires, and drought. The team has now completed 4 science flights as well as 1 functional check flight. The flights covered the Santa Barbara Box, Ivanpah Playa (at the border between CA and NV), and other areas in southern California. WDTS will likely extend until 31 May since aircraft maintenance and weather have caused some campaign delays. Link: https://airbornescience.nasa.gov/flight_reports/ER-2_-_AFRC_809_03_24_21

MODIS quicklook data from the 24 March WDTS flight over southern California imaged the San Gabriel Mountains with prominent fire scars from several fire seasons, including the 2019 Tick Fire, and other fires (bright yellow areas in RGB). Image oriented with north facing the top of the page.

UPCOMING MEETINGS/EVENTS/CONFERENCES

Date Name Who, What (location), and Time

23-25 March Space Ryan Spackman attended the plenary session on 23 March and the open 2021 Science session of the Committee on Earth Science and Applications from Week 2021 Space (CESAS) on 24 March. (virtual The event aims to discuss recent advances in space and Earth science, hear meeting) from federal agencies about upcoming projects, and explore future opportunities. Link: https://www.nationalacademies.org/event/03-23-2021/space-science- week-2021

26 March Asia Oceania Florian Schwandner attends the AOGS Annual General Meeting (AGM) 2021 Geoscience as Solid Earth (SE) Section President. Society (AOGS) The AGM is an assembly to brief the membership on the activities of the 2021 Annual society during the past year, on society finances, and to elect honorary General Meeting members. AOGS is the third largest broad international geoscience society (AGM) after AGU and EGU, and holds joint events and meetings with both. (virtual meeting) Normally the AGM is held on the last day of the annual science meeting, but due to the pandemic, it is held separately and virtually. Schwandner was elected AOGS SE section president in 2019. Link: https://www.asiaoceania.org/

AWARDS AND RECOGNITIONS

• N/A

PROJECT MILESTONES

• NASA Ames recently returned from Restricted Stage 3 to Stage 3 in the NASA Response Framework to pandemics – Staff are continuing work with adjustments in work style, focus and schedules due to the COVID-19 distancing protocols. ESPO-managed NASA airborne missions and other programs and projects at Ames are experiencing major schedule delays due to COVID-19. Ames Earth Science Division staff are focusing on data analysis, publications, proposals, and computer-aided design work. The division is actively engaged with the Science Directorate and center and with HQ on prioritizing mission-critical activities, preparing return-to-onsite-work (RTOW) implementation plans to ensure maximum personnel safety.

• The ESPO-managed Convective Processes Experiment – Aerosols & Winds (CPEX-AW) international airborne investigation made the decision on 15 March 2021 to continue toward a summer deployment. ESPO is preparing a RTOW plan for center review. Travel to Puerto Rico for a site visit is planned for April. (https://espo.nasa.gov/cpex-aw)

• The Sub-Mesoscale Ocean Dynamics Experiment (S-MODE) Earth Venture Suborbital-3 (EVS-3) investigation, based from Moffett Field at ARC and managed by ESPO, has received approval for RTOW at ARC. Originally delayed from fall 2020 until March/April 2021, the PI recently made the decision to further postpone the next field campaign to fall 2021. (https://espo.nasa.gov/s-mode/content/S-MODE)

• The EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) international shipborne field campaign, funded by NASA SMD’s Ocean Biology & Biogeochemistry Program, with logistics managed by ESPO, is continuing to plan for a 2021 deployment out of Southampton, UK. The RTOW plan submitted for center review was approved 8 March 2021, and the logistics team is currently on travel to preparing shipments for the deployment. (https://espo.nasa.gov/content/EXPORTS)

• Instrument payload readiness activities at Ames for the Asian Summer Monsoon Chemical and Climate Impact Project (ACCLIP) have also received approval for preparation for the field campaign, now planned for summer 2022 in South Korea. IIntegration flights are currently scheduled for summer 2021 on the NASA WB-57F out of Ellington Field at JSC. (https://airbornescience.nasa.gov/instrument/COMA) (https://espo.nasa.gov/acclip)

• The Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) EVS-3 investigation, managed by ESPO, has received approval for RTOW at ARC. The PI recently made the decision to delay IMPACTS by one year, until the winter of 2021/22. (https://espo.nasa.gov/impacts)

• The ESPO-managed Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) EVS-3 investigation, with science and instrument team members at ARC, submitted a RTOW plan for center review on 22 March 2021. (https://espo.nasa.gov/dcotss)

• The Ames Earth Science Interdisciplinary Science (IDS) funded project RUMMBLE concluded a field campaign conducted by a joint team of co-I Chad Deering and students and Costa Rican researchers and students. The team successfully mapped volcanic CO2 soil gas emissions on the craters and vegetated flanks of Turrialba and Irazu volcanoes, Costa Rica, during a period of quiescence. RUMMBLE, led by Steve Broccardo, includes investigators at Ames, JPL, Caltech, Michigan Technological University (MTU), the University of Alaska Fairbanks, and collaborators in Costa Rica. The project integrates solid Earth and atmospheric science perspectives and observables to better

constrain aerosol effects on CO2 retrievals of OCO-2 and OCO-3 data over dense volcanic plumes.

PUBLICATIONS

Publication Journal/Web link

Semantic Segmentation of High Resolution Satellite Imagery Edward Collier, Supratik Mukhopadhyay, using Generative Adversarial Networks with Progressive Growing Kate Duffy, Sangram Ganguly, Geri Madanguit, Subodh Kalia, Gayaka Abstract: Shreekant, Ramakrishna Nemani, Andrew Michaelis, Shuang Li & Auroop Ganguly With increase in urbanization and Earth Sciences research into urban (2021), Semantic Segmentation of High Resolution Satellite Imagery using areas, the need to quickly and accurately segment urban rooftop maps Generative Adversarial Networks with has never been greater. Current machine learning techniques struggle Progressive Growing, Remote Sensing to produce high accuracy maps in dense urban zones where there is Letters, 12:5, 439-448. high image noise and foot print overlap. In this paper, we evaluate a

training methodology for pixel-wise segmentation for high-resolution satellite imagery using progressive growing of generative adversarial DOI: networks as a solution. We apply our model to segmenting building https://doi.org/10.1080/2150704X.2021.189 rooftops and compare these results to conventional methods for 5444 rooftop segmentation. We evaluate our approach using the SpaceNet version 2 and xView datasets. Our experiments show that for SpaceNet, progressive Generative Adversarial Network (GAN) training achieved a test accuracy of 93% compared to 89% for traditional GAN training and 87% for U-Net architecture, while for xView, we achieved 71% accuracy using progressive GAN training compared to 69% through traditional GAN training and 65% using U-Net.

Impact Statement: Using newer methods of machine learning, this study showed significantly improved classification accuracy for identifying rooftops in high spatial resolution commercial satellite imagery. The first author is a NASA Pathways intern with the NASA Earth Exchange (NEX).

SCIENCE COMMUNICATION STORIES

• Florian Schwandner was featured in a radio report of Deutsche Welle (in English), the German international broadcasting service, on how non-eruptive volcanic CO2 emissions affect tropical trees. The “Living Planet” series covered a story on how forests growing on active volcanoes in Costa Rica take up extra carbon from subtle

emissions of volcanic CO2 seeping upward through the ground into overlying forests. Learning how these trees respond to excess CO2 points to a potential tool for future spaceborne remote sensing instruments to use trees as proxy CO2 sensors to capture precursory upticks in emissions months to years before eruptions at subtle levels not directly

measurable by OCO-2 or OCO-3. These volcanic forests bathing in excess CO2 continuously also provides a window

into the future of our planet, a natural experiment simulating high-CO2 atmospheres of the future. Schwander co-leads this multi-center initiative together with JPL.

Link:https://www.dw.com/en/living-planet-capturing-carbon-in-costa-rica/av-56914687 (this story only) Link: https://www.dw.com/en/living-planetlong-suffering-indispensable-trees/av-56916186 (full story)

SPACE SCIENCE & ASTROBIOLOGY DIVISION HIGHLIGHTS SS Weekly Report

Date: 26 March 2021 Division: SS

SIGNIFICANT ANNOUNCEMENTS

• A dozen division scientists from SST and SSA contributed to 13 of the 24 articles in the Icarus special issue: Pluto System, Kuiper Belt, and Kuiper Belt Objects. In addition, Oliver White (SST/SETI) was on the editorial board for the issue. A full list of papers and authors is found in the publications section below. https://www.sciencedirect.com/journal/icarus/vol/356/suppl/C

• Thayne Currie (SSA/USRA), Eugene Pluzhnik (BAERI), and Ruslan Belikov (SSA) led the successful completion of Milestone 1 for NASA-Strategic Astrophysics Technology project entitled “Linear Wavefront Control”, using the Ames Coronagraphic Experiment testbed.

• Scott Sandford (S) participated in an all-day OSIRIS-REx Sample and Curation Technical Interchange Meeting held on March 19, 2021. The purpose of this meeting was to begin the detailed coordination of the tasks associated with the curation and analysis of samples to be returned from asteroid Bennu by the OSIRIS-REx spacecraft in 2023. Dr. Sandford presented material associated with the analysis of components of the Sample Return Capsule.

• SOFIA Workshop: Rock, Dust, and Ice happened this week. Many of our researchers participated by giving talks and/or chairing sessions during this workshop. Please see list of presentations in the meetings section below.

MEETINGS/EVENTS/CONFERENCES

SOFIA Workshop: Rock, Dust and Ice https://sofia-science-series.constantcontactsites.com/

o Ella Sciamma-O’Brien (SSA) gave an invited talk at the SOFIA Workshop: Rock, Dust and Ice. The goal of this workshop is to foster the exchange of information between lab astronomers, modelers and observers working with planetary surfaces, with a focus on the interpretation of data from satellites and ground-based telescopes. Ella Sciamma- O’Brien gave an overview talk on the area of her work related to laboratory studies of solar system materials.

o Dale Cruikshank (SSA) gave an invited talk at the SOFIA Workshop: Rock, Dust and Ice. Dale gave an overview of his work related to Ices and Organics in the Outer Solar System to make connections to the Solar Nebula and Protoplanetary Disk on Day 2 (03/24) between 8am – 11:30am PST.

o Joe Roser (SSA/SETI gave an invited talk at the SOFIA Workshop: Rock, Dust and Ice. He presented work from the Laboratory Astrophysics ISFM titled “The Laboratory Astrophysics Optical Constants Database” at 10:25am on 03/25. o Maggie McAdam (SSA) will be moderating the Planetary Surfaces in Practice Panel Discussions from 8am – 11:30am PST on Day 4 (03/26) of this workshop. o Joe Roser (SSA/SETI) was a panelist on the Laboratory Databases Panel at 9am on Day 4 (03/26) of this workshop.

American Chemical Society Meeting Conference https://www.acs.org/content/acs/en/meetings/acs-meetings.html

o Scott Sandford (SSA) and team gave a presentation at the American Chemical Society Meeting (March 21-25, 2021) entitled “The OSIRIS-REx Sample Return Mission – Looking for Signs of Primitive Astrochemical Complexity in Asteroid (101955) Bennu.”

Planetary Defense Conference 2021 https://iaaspace.org/event/7th-iaa-planetary-defense-conference-2021/

o Jessie Dotson (SS), Lorien Wheeler (TNP), Clemens Rumpf (TNP), and Donovan Mathias (TN) will be giving a presentation titled “Bayesian Inference of Asteroid Physical Properties: Application to Impact Scenarios” at the Planetary Defense Conference 2021 April 26 – 30, 2021.

Japan Geoscience Union http://www.jpgu.org/en/

o Scott Sandford (SSA) has been invited to give a lecture at the June 2021 meeting of the Japan Geoscience Union in which he will talk about the astrobiological significance of soluble and insoluble organics returned from comets and asteroids by the Stardust, OSIRIS-REx, Hayabusa, and Hayabusa2 sample return missions."

Date Name Who, What (location), and Time March 23-26, American Physical - Link: https://meetings.aps.org/Meeting/MAR21/Content/3990 2021 Society March Meeting - Location: Virtual Time: 6:00am -4:00pm PST Network for Ocean - Title: Signatures of Life: Detection and Characterization March 29, Worlds Seminar - Richard Quinn (SSX) and Marc Neveu, GSFC 2021 - Location: Webex Meeting Number (access code)199 088 1228 Meeting password: 123 Local: 818-354-4044 - Toll Free: 844-JPL-WEBX (844-575-9329) - Time 10:00 AM Pacific

April 5-16, American - Link: https://www.acs.org/content/acs/en/meetings/acs-meetings.html 2021 Chemical - Location: Virtual Society Spring 2021

April 26 – 30, Planetary - Link: https://iaaspace.org/event/7th-iaa-planetary-defense-conference- 2021 Defense 2021/ Conference - Location: Vienna, Austria (Virtual) 2021 Emerging May 24 – 26, - Tilte: Early career exoplanet scientists Researchers in 2021 - Link: https://eres2021.com Exoplanet Science Symposium (ERES) - Time: 10:00 AM – 2:00 PM Pacific VI

May 30 – June Japanese http://www.jpgu.org/en/ 1, 2021 (in Geophysical - Location: Yokohama, Japan & Virtual person) Union June 3-6, 2021 (Virtual) August 7-12, SmallSat 2021- https://smallsat.org/ 2021 Mission Operations & Autonomy

AWARDS AND RECOGNITIONS

• Pasquale Temi (SSA) has been awarded an FY21 Ames Research Innovation Award (ARIA), for his proposal titled “Addressing weaknesses in the Science case for the X-Ray Grating Spectrometer Mission Arcus.” The goal of this proposal is to refine and optimize the Mission Science definition and preparation, for the MIDEX class high-resolution X- ray grating spectrometer mission Arcus. Given the excellent feedback from past review and the strong Ames interest and investment in the mission, this study focuses on retiring a Science Weakness identified in last review. Arcus is a NASA/MIDEX mission under development. It is a free-flying, soft X-ray grating spectrometer with the highest-ever spectral resolution in the 8-51 Å (0.2-2 keV) energy range. The Arcus bandpass includes the most sensitive tracers of diffuse million degree gas: spectral lines from O VII and O VIII, H- and He-like lines of C, N, Ne and Mg, and unique density- and temperature-sensitive lines from Si and Fe ions. These capabilities enable an advance in our understanding of the formation and evolution of baryons in the Universe that is unachievable with any other present or planned observatory.

PROJECT MILESTONES

• Scott Sandford (S) participated in an all-day OSIRIS-REx Sample and Curation Technical Interchange Meeting held on March 19, 2021. The purpose of this meeting was to begin the detailed coordination of the tasks associated with the curation and analysis of samples to be returned from asteroid Bennu by the OSIRIS-REx spacecraft in 2023. Dr. Sandford presented material associated with the analysis of components of the Sample Return Capsule.

PUBLICATIONS

Publications from Special Issue of Icarus: Pluto System, Kuiper Belt, and Kuiper Belt Objects

• TITLE: MORPHOLOGICAL COMPARISON OF BLOCKS IN CHAOS TERRAINS ON PLUTO, EUROPA, AND MARS Authors: Helle L. Skjetnea, Kelsi N. Singer, Brain M. Hynek, Katie L. Knight, Paul M. Schenk, Cathy B.Olkin, Oliver, L. White (SST/SETI), Tanguy Bertrand (SST/USRA), Kirby D. Runyon, William B. McKinnon, Jeffrey M. Moore (SST), S Alan Stern, Harold A. Weaver, Lesie, A. Young, Kim Ennico (SSA) --- Short Abstract: Chaotic terrains are characterized by disruption of preexisting surfaces into irregularly arranged mountain blocks with a “chaotic” appearance. Several models for chaos formation have been proposed, but the formation and evolution of this enigmatic terrain type has not yet been fully constrained. We provide extensive mapping of the individual blocks that make up different chaos landscapes, and present a morphological comparison of chaotic terrains found on Pluto, Jupiter's Moon Europa, and Mars, using measurements of diameter, height, and axial ratio of chaotic mountain blocks. Additionally, we compare mountain blocks in chaotic terrain and fretted terrain on Mars. We find a positive linear relationship between the size and height of chaos blocks on Pluto and Mars, whereas blocks on Europa exhibit a flat trend as block height does not generally increase with increasing block size. Block heights on Pluto are used to estimate the block root depths if they were floating icebergs. Block heights on Europa are used to infer the total thickness of the icy layer from which the blocks formed. Finally, block heights on Mars are compared to potential layer thicknesses of near-surface material. We propose that the heights of chaotic mountain blocks on Pluto, Europa, and Mars can be used to infer information about crustal lithology and surface layer thickness. https://doi.org/10.1016/j.icarus.2020.113866

• Title: Cryovolcanic flooding in Viking Terra on Pluto Authors: Dale P. Cruikshank (SSA), Cristina M. Dalle Ore (SSA/SETI), Francesca Scipioni (SSA/SETI), Ross A. Beyer (SST/SETI), Oliver L. White (SST/SETI), Jeffrey M. Moore (SST), William M. Grundy, Bernard Schmitt, Kirby D. Runyon, James T. Keane, Stuart J. Robbins, S. Alan Stern, Tanguy Bertrand (SST/USRA), Chloe B. Beddingfield(SST/SETI), Catherine B. Olkin, Leslie A. Young, Harold A. Weaver, Kimberly Ennico (SSA) -- Short Abstract: A prominent fossa trough (Uncama Fossa) and adjacent 28-km diameter impact crater (Hardie) in Pluto's Viking Terra, as seen in the high-resolution images from the New Horizons spacecraft, show morphological evidence of in-filling with a material of uniform texture and red-brown color. A linear fissure parallel to the trough may be the source of a fountaining event yielding a cryoclastic deposit having the same composition and color properties as is found in the trough and crater. Spectral maps of this region with the New Horizons LEISA instrument reveal the spectral signature of H2O ice in these structures and in distributed patches in the adjacent terrain in Viking Terra. A detailed statistical analysis of the spectral maps shows that the colored H2O ice filling material also carries the 2.2-μm signature of an ammoniated component that may be an ammonia hydrate (NH3·nH2O) or an ammoniated salt. This paper advances the view that the crater and fossa trough have been flooded by a cryolava debouched from Pluto's interior along fault lines in the trough and in the floor of the impact crater. The now frozen cryolava consisted of liquid H2O infused with the red-brown pigment presumed to be a tholin, and one or more ammoniated compounds. Although the abundances of the pigment and ammoniated compounds entrained in, or possibly covering, the H2O ice are unknown, the strong spectral bands of the H2O ice are clearly visible. In consideration of the factors in Pluto's space environment that are known to destroy ammonia and ammonia-water mixtures, the age of the exposure is of order ≤109 years. Ammoniated salts may be more robust, and laboratory investigations of these compounds are needed. https://doi.org/10.1016/j.icarus.2020.113786

• Title: Global compositional cartography of Pluto from intensity-based registration of LEISA data Authors: L.R. Gabasova, B. Schmitt, W. Grundy, T. Bertrand (SST/USRA), C. B. Olkin, J.R. Spencer, L. A. Young, K. Ennico (SSA), H. A. Weaver, S. A. Stern and the New Horizons Composition Team -- Short Abstract: In 2015 the New Horizons spacecraft reached the Pluto system and returned unprecedentedly detailedmeasurements of its surface properties. These measurements have already been integrated into globalreflectance, topography and narrow-band multispectral surface maps. However, analysis of the hyperspectraldata from the Ralph/LEISA infrared spectrometer, which lets us analyse the surface composition, has untilnow been confined to the high-resolution encounter hemisphere of Pluto. We use an innovative technique— intensity-based registration — to co-register this high-resolution data with lower- resolution measurementstaken during the spacecraft’s approach, and present the first global qualitative composition maps for CH4, N2and H2O ice, and a tholin-like red material. We compare these maps with the other maps produced for Plutoand study the global extent of the previously-described latitudinal distribution of the surface components,which is relatively longitudinally constant with the exception of Sputnik Planitia. We also correlate thesecompositional components with geological features and propose physical interpretations, which include: CH4-ice-rich dissected plateaus in high northern latitudes, CH4-rich eroded terrain with N2-rich infill in mediumnorthern latitudes, CH4-rich bladed terrain in low northern latitudes, and a red material belt overlaying H2Oice in low southern latitudes. https://doi.org/10.1016/j.icarus.2020.113833

• Title: Pluto’s far side Authors: S. A. Stern, O. L. White (SST/SETI), P. J. McGovern, J. T. Keane (NASA JPL), J. W. Conrad, C. J. Bierson, T. R. Lauer, C. B. Olkin, L. A. Young, P. M. Schenk, J.M. Moore (SST), H. A. Weaver, K. D. Runyon, K. Ennico (SSA), The New Horizons Team. --- Short Abstract: The New Horizons spacecraft provided near- global observations of Pluto that far exceed the resolution of Earth-based datasets. However, most previous Pluto New Horizons analyses focused on the New Horizons encounter hemisphere (i.e., the anti-Charon hemisphere containing Sputnik Planitia). In this work, we summarize and interpret data on Pluto's “far side” (i.e., its non-encounter or alternatively, its sub-Charon hemisphere), providing the first integrated New Horizons overview of Pluto's far side terrains. We find strong evidence for widespread bladed (i.e., aligned CH4-mountain) deposits, evidence for an impact crater about as large as any on the “near side” hemisphere, evidence for complex lineations approximately antipodal to Sputnik Planitia that may be causally related, evidence that the far side maculae (i.e., equatorial dark regions) are smaller and more structured than Pluto's encounter hemisphere maculae, and more. https://doi.org/10.1016/j.icarus.2020.113805

• Title: Distribution and energy balance of Pluto’s nitrogen ice, as seen by New Horizons in 2015 Authors: Briley L. Lewis, John A. Stansberry, Bryan J. Holler, William M. Grundy, Bernard Schmitt, Sylvia Protopapa, Carey Lisse, S. Alan Stern, Leslie Young, Harold A. Weaver, Catherine Olkin, Kimberly Ennico (SSA), New Horizons Science Team -- Short Abstract: Pluto’s surface is geologically complex because of volatile ices that are mobile on seasonal and longer timescales. Here we analyzed New Horizons LEISA spectral data to globally map the nitrogen ice, including nitrogenwith methane diluted in it. Our goal was to learn about the seasonal processes influencing ice redistribution, tocalculate the globally averaged energy balance, and to place a lower limit on Pluto’s N2inventory. We presentthe average latitudinal distribution of nitrogen and investigate the relationship between its distribution andtopography on Pluto by using maps that include the shifted bands of methane in solid solution with nitrogen(which are much stronger than the 2.15-μm nitrogen band) to more completely map the distribution of thenitrogen ice. We find that the global average bolometric albedo is 0.83 ± 0.11, similar to that inferred forTriton, and that a significant fraction of Pluto’s N2is stored in Sputnik Planitia. We also used the encounter-hemisphere distribution of nitrogen ice to infer the latitudinal distribution of nitrogen over the rest of Pluto,allowing us to calculate the global energy balance. Under the assumption that Pluto’s nitrogen-dominated 11.5μbar atmosphere is in vapor pressure equilibrium with the nitrogen ice, the ice temperature is 36.93 ± 0.10K,as measured by New Horizons’ REX instrument. Combined with our global energy balance calculation, thisimplies that the average bolometric emissivity of Pluto’s nitrogen ice is probably in the range 0.47–0.72. This isconsistent with the low emissivities estimated for Triton based on Voyager results, and may have implicationsfor Pluto’s atmospheric seasonal variations, as discussed below. The global pattern of volatile transport at thetime of the encounter was from north to south, and the transition between condensation and sublimationwithin Sputnik Planitia is correlated with changes in the grain size and CH4concentration derived from thespectral maps. The low emissivity of Pluto’s N2ice suggests that Pluto’s atmosphere may undergo an extendedperiod of constant pressure even as Pluto recedes from the Sun in its orbit. https://doi.org/10.1016/j.icarus.2020.113633

• TITLE: HAZE IN PLUTO'S ATMOSPHERE: RESULTS FROM SOFIA AND GROUND-BASED OBSERVATIONS OF THE 2015 JUNE 29 PLUTO OCCULTATION Authors: Michael J. Persona, Amanda S. Bosh, Carlos A. Zuluaga, Amanda A. Sickafoose, Stephen E. Levine, Jay M. Pasachoff, Bryce A. Babcock, Edward W. Dunham, Ian S. McLeane, Jürgen Wolff, Fumio Abe, E.E. Becklin, Thomas A. Bida, Len P. Bright, Tim Brothers, Grant Christie, Rebecca F. Durst, Alan C. Gilmore, Ryan T. Hamilton, Hugh C. Harris, Chris Johnson, Pamela M. Kilmartin, Molly Kosiarek, Karina Leppik, Sarah E. Logsdon (NASA GSFC), Robert Lucas, Shevill Mathers, C.J.K. Morley, Peter Nelson, Haydn Ngan, PfullerEnrico Pfüller, Tim Natusch, Stephanie Sallum, Maureen L. Savage, Christina H. Seeger, Ho Chit Siu, Chris Stockdale, Daisuke Suzuki, Thanawuth Thanathibodee, Trudy Tilleman, Paul J. Tristram, William D. Vacca, Jeffrey Van Cleve (SSA/SETI), Carolle Varughese, Luke W. Weisenbach, Elizabeth Widen, Manuel Wiedemann (PX) [DLR] -- Short Abstract: On UT 29 June 2015, the occultation by Pluto of a bright star (r′ = 11.9) was observed from the Stratospheric Observatory for Infrared Astronomy (SOFIA) and several ground-based stations in New Zealand and Australia. Pre- event astrometry allowed for an in-flight update to the SOFIA team with the result that SOFIA was deep within the central flash zone (~22 km from center). Analysis of the combined data leads to the result that Pluto's middle atmosphere is essentially unchanged from 2011 and 2013 (Person et al. 2013; Bosh et al. 2015); there has been no

significant expansion or contraction of the atmosphere. Additionally, our multi-wavelength observations allow us to conclude that a haze component in the atmosphere is required to reproduce the light curves obtained. This haze scenario has implications for understanding the photochemistry of Pluto's atmosphere. https://doi.org/10.1016/j.icarus.2019.113572

• TITLE: ON THE ORIGIN & THERMAL STABILITY OF ARROKOTH’S AND PLUTO’S ICES Authors: C.M. Lisse, A. Young, D. P. Cruikshank (SSA), S. A. Sandford (SSA), B. Schmitt, S. A. \Stern, H. A. Weaver, O. Umurhan (SST/SETI), Y.J. Pendelton (SST), J. T. Keane, G. R. Gladstone, J. M. Parker, R. P. Binzel, A. M. Earle, M. Hornayi, M. R. El-Maarry, A. F. Cheng, J. M. Moore (SST), W. B. McKinnon, W.M. Gundy, J. H. Kavelaars, L. R. Linscott, W. Lyra, B. L. Lewis, D. T. Britt, J. R. Spencer, C. B. Olkin, R. L. McNutt, H. A. Elliot, N. Dello-Russo, J. K. Steckloff, M. Neveu, O Mousis --- Short Abstract: In this paper we discuss in a thermodynamic, geologically empirical way the long-term nature of the stable majority ices that could be present in Kuiper Belt object (KBO) 2014 MU69 (also called Arrokoth; hereafter “MU69”) after its 4.6 Gyr residence in the Edgeworth-Kuiper belt (EKB) as a cold classical object. We compare the upper bounds for the gas production rate (~1024 molecules/s) measured by the New Horizons (NH) spacecraft flyby on 01 Jan 2019 to estimates for the outgassing flux rates from a suite of common cometary and KBO ices at the average ~ 40 K sunlit surface temperature of MU69, but do not find the upper limit very constraining except for the most volatile of species (e.g. CO, N2, CH4). More constraining is the stability versus sublimation into vacuum requirement over Myr to Gyr, and from this we find only 3 common ices that are truly refractory: HCN, CH3OH, and H2O (in order of increasing stability), while NH3 and H2CO ices are marginally stable and may be removed by any positive temperature excursions in the EKB, as produced every 108–109 years by nearby supernovae and passing O/B stars. To date the NH team has reported the presence of abundant CH3OH and H2O on MU69's surface (Stern et al., 2019; Grundy et al., 2020). NH3 has been searched for, but not found. We predict that future absorption feature detections, if any are ever derived from higher signal-to-noise ratio spectra, will be due to an HCN or poly-H2CO based species. Consideration of the conditions present in the EKB region during the formation era of MU69 lead us to state that it is highly likely that it “formed in the dark”, in an optically thick mid-plane, unable to see the nascent, variable, highly luminous Young Stellar Object (YSO)/TTauri Sun, and that KBOs contain HCN and CH3OH ice phases in addition to the H2O ice phases found in their short period (SP) comet descendants. Finally, when we apply our ice thermal stability analysis to bodies/populations related to MU69, we find that methanol ice is likely ubiquitous in the outer solar system; that if Pluto isn't a fully differentiated body, then it must have gained its hypervolatile ices from proto-planetary disk (PPD) sources in the first few Myr of the solar system's existence; and that hypervolatile rich, highly primordial comet C/2016 R2 was placed onto an Oort Cloud orbit on a similar few Myr timescale. https://doi.org/10.1016/j.icarus.2020.114072

• TITLE: Modeling Pluto’s minimum pressure: Implications for haze production Authors: P.E. Johnson, L. A. Young, S. Protopapa, B. Schmidt, L. R. Gabasova, B. L. Lewis, J. A. Stansberry, K. E. Mandt, O. L. White (SST/SETI) – Short Abstract: Pluto has a heterogeneous surface, despite a global haze deposition rate of ∼ 1μm per orbit (Cheng et al., 2017; Grundy et al., 2018). While there could be spatial variation in the deposition rate, this has not yet been rigorously quantified, and naively the haze should coat the surface more uniformly than was observed. One way (among many) to explain this contradiction is for the atmospheric pressure at the surface to drop low enough to interrupt haze production and stop the deposition of particles onto part of the surface, driving heterogeneity. If the surface pressure drops to less than 10−3 - 10−4 μbar and the CH4 mixing ratio remains nearly constant at the observed 2015 value, the atmosphere becomes transparent to ultraviolet radiation (Young et al., 2018), which would shut off haze production at its source. If the surface pressure falls below 0.06 μbar, the atmosphere ceases to be global, and instead is localized over only the warmest part of the surface, restricting the location of deposition (Spencer et al., 1997). In Pluto’s current atmosphere, haze monomers collect together into aggregate particles at beginning at 0.5 μbar; if the surface pressure falls below this limit, the appearance of particles deposited at different times of year and in different locations could be different. We use VT3D, an energy balance model (Young, 2017), to model the surface pressure on Pluto in current and past orbital configurations for four possible static N2 ice distributions: the observed northern hemisphere distribution with (1) a bare southern hemisphere, (2) a south polar cap, (3) a southern zonal band, and finally (4) a distribution that is bare everywhere except inside the boundary of Sputnik Planitia. We also present a sensitivity study showing the effect of

mobile N2 ice. By comparing the minima of the modeled pressures to the three haze-disruption pressures, we can

determine if or when haze production is disrupted. We find that Pluto’s minimum surface pressure in its current orbit is predicted to be between 0.01 and 3 μbar, and that over the past 10 million years the surface pressure has not fallen

below 0.004 μbar. According to our model, southern N2 ice is required for haze aggregation to be interrupted, and

southern N2 with very low thermal inertia is required for the possibility of a local atmosphere. https://doi.org/10.1016/j.icarus.2020.114070

• TITLE: Depths of Pluto’s and Charon’s craters, and their simple-to-complex transition Authors: Stuart J.Robbins, Paul M.Schenk, Jamie D.Riggs, Alex H.Parker, Veronica J.Bray, Chloe B.Beddingfield (SST/SETI), Ross A.Beyer(SST/SETI), Anne J.Verbiscer, RichardBinzel, Kirby D.Runyon – Short Abstract: Impact craters form as point- like explosions on solar system bodies, excavating a cavity within the surface. Most information about the impactor itself is lost, save its energy, such that the target itself controls much of the final crater size and shape given the energy input. For this reason, impact craters are a useful probe of surface differences across a single body and between bodies. Two properties that are commonly used to compare craters from one body to another are the ratio between crater depth and diameter, and the diameter at which craters transition between simple, bowl-shaped morphologies to more complex morphologies that include flat floors, central peaks, wall terraces, and scalloped rims. Both metrics are important as input into theoretical models and for probing the strength of the surface material. In this work, we have measured these properties on Pluto and Charon and report on the results. However, the analysis is not entirely straightforward; a secondary goal of this work is to explore how to measure and quantify the two properties accurately (depth vs diameter and simple-to-complex transitions). We arrive at different results based on the method, and we report on that variation as a way to reasonably estimate the uncertainty in each quantity. For those reasons, it is difficult to place a single, exact value on each, but we do conclude that the morphology-based simple-to-complex transition occurs at approximately 11– 12½ km on Pluto, and 13½–16 km on Charon. We also conclude that the existing, public topography data for at least Charon is likely too low in resolution to measure the simple crater depth vs diameter function accurately, such that a morphometry-based simple-to-complex transition diameter is not quantifiable at this time. https://doi.org/10.1016/j.icarus.2020.113902

• TITLE: Global climate model occultation lightcurves tested by August 2018 ground-based stellar occultation. Authors: Sihe Chen, Eliot F.Young, Leslie A.Young, Tanguy Bertrand (SST/USRA), François Forget, Yuk L.Yunga – Short Abstract: Pluto's atmospheric profiles (temperature and pressure) have been studied for decades from stellar occultation lightcurves. In this paper, we look at recent Pluto Global Climate Model (GCM) results (3D temperature, pressure, and density fields) from Bertrand et al. (2020) and use the results to generate model observer's plane intensity fields (OPIF) and lightcurves by using a Fourier optics scheme to model light passing through Pluto's atmosphere (Young, 2012). This approach can accommodate arbitrary atmospheric structures and 3D distributions of haze. We compared the GCM model lightcurves with the lightcurves observed during the 15-AUG-2018 Pluto stellar occultation. We find that the climate scenario which best reproduces the observed data includes a N2 ice mid latitude band in the southern hemisphere. We have also studied different haze and P/T ratio profiles: the haze effectively reduces the central flash strength, and a lower P/T ratio both reduces the central flash strength and incurs anomalies in the shoulders of the central flash. https://doi.org/10.1016/j.icarus.2020.113976

• TITLE: Lorri observations of waves in Pluto’s atmosphere. Authors: Adam D.Jacobs, Michael E.Summers, Andrew F.Cheng, G. Randall Gladstone, Carey M.Lisse, W. Dean Pesnell, Tanguy Bertrand (SST/SETI), Darrell F.Strobel, Leslie A.Young, Harold A.Weaver, Joshua Kammer, Peter Gao – Short Abstract: Observations during the New Horizons (NH) spacecraft flyby of Pluto in July 2015 revealed that Pluto's atmosphere supports an extensive circumplanetary haze with embedded layers, suggesting several possible microphysical and/or dynamical excitation processes. The purpose of this paper is to build upon existing observations and analyses of Pluto's atmosphere— specifically of the complex haze layer structures—to identify wave structure in Pluto's atmosphere. Here three NH/Long Range Reconnaissance Imager (LORRI) image sequences from the flyby at high phase angles (148°–169°) and three different resolutions (0.093 km/pix, 0.96 km/pix, and 3.86 km/pix) are analyzed. Several haze layer characteristics were extracted, namely—slope, amplitude, waveform, and the associated power spectral densities (PSDs); and their variations with local geography. These are then explored in the context of possible wave types in Pluto's atmosphere,

such as tidal and orographically driven inertia-gravity (buoyancy) waves. PSD peaks at 8–10 km and 18–22 km vertical wavelength are found in NH images, which is consistent with the perturbations seen in Earth-based stellar occultations of Pluto's atmosphere. The 8–10 km signals are localized to low-latitudes and equatorial regions and the 18–22 km signals are more globally distributed. Haze layer background relative amplitudes were found to be around 0.01–0.04. Slopes of layers were found to be correlated with the emergence and disappearance of a 25 km layer around 30°N. An amplitude increase of oscillations below 30 km altitude exists in the high-resolution image sequence. These findings indicate the possibility of waves in Pluto's atmosphere and motivate further studies of wave dynamics combining NH data with state-of-the-art models of Pluto's atmosphere. These results are important because they can provide strong constraints to models and to the type of waves that can be present in Pluto's atmosphere. https://doi.org/10.1016/j.icarus.2020.113825

• TITLE: Photometry of Kuiper belt object (486958) Arrokoth from New Horizons LORRI. Authors: Jason D.Hofgartner, Bonnie J.Buratti, Susan D.Benecchi, Ross A.Beyer (SST/SETI), Andrew Cheng, James T.Keane, Tod R.Lauer, Catherine B.Olkin, Joel W.Parker, Kelsi N.Singer, John R.Spencer, S. AlanStern, Anne J.Verbiscer, Harold A.Weaver, New Horizons Geology and Geophysics Team, New Horizons LORRI Team – Short Abstract: On January 1st 2019, the New Horizons spacecraft flew by the classical Kuiper belt object (486958) Arrokoth (provisionally designated 2014 MU69), possibly the most primitive object ever explored by a spacecraft. The I/F of Arrokoth is analyzed and fit with a photometric function that is a linear combination of the Lommel-Seeliger (lunar) and Lambert photometric functions.

Arrokoth has a geometric albedo of pv = 0.21 / +0.05 / -0.04 at a wavelength of 550 nm and ≈0.24 at 610 nm. Arrokoth's geometric albedo is greater than the median but consistent with a distribution of cold classical Kuiper belt objects whose geometric albedos were determined by fitting a thermal model to radiometric observations. Thus, Arrokoth's geometric albedo adds to the orbital and spectral evidence that it is a cold classical Kuiper belt object. Maps of the normal reflectance and hemispherical albedo of Arrokoth are presented. The normal reflectance of Arrokoth's surface varies with location, ranging from ≈0.10–0.40 at 610 nm with an approximately Gaussian distribution. Both Arrokoth's extrema dark and extrema bright surfaces are correlated to topographic depressions. Arrokoth has a bilobate shape and the two lobes have similar normal reflectance distributions: both are approximately Gaussian, peak at ≈0.25 at 610 nm, and range from ≈0.10–0.40, which is consistent with co-formation and co-evolution of the two lobes. The hemispherical albedo of Arrokoth varies substantially with both incidence angle and location, the average hemispherical albedo at 610 nm is 0.063 ± 0.015. The Bond albedo of Arrokoth at 610 nm is 0.062 ± 0.015. https://doi.org/10.1016/j.icarus.2020.113723

• Title: Origins of pits and troughs and degradation on a small primitive planetesimal in the Kuiper Belt: high-resolution topography of (486958) Arrokoth (aka 2014 MU69) from New Horizons. Authors: Paul Schenk, Kelsi Singer, Ross Beyer (SST/SETI), Chloe Beddingfield (SST/SETI), Stuart J.Robbins, William B.McKinnon, Tod R.Lauer, Anne J.Verbiscer, James.T.Keane, Rajani D.Dhingra, Jeffrey Moore (SST), Joel W.Parker, Cathy Olkin, John Spencer, Ha lWeaver, S. Alan Stern – Short Abstract: The dominant topographic features on two-lobed Kuiper Belt object (486958) Arrokoth (provisionally designated 2014 MU69) are scattered, small, circular depressions or pits up to ~1.0 km across and curvilinear troughs observed near the terminator during the New Horizons encounter of 01 January 2019. With important exceptions, evidence for an endogenic origin for pits is lacking and impact remains the most likely origin. Pit depths relative to the local surface are shallower than hypervelocity simple craters on icy moons and consistent with low velocity (~300 m/s) impacts in an icy target (the role of porosity and cohesion in cratering on Arrokoth being uncertain). There is, however, a large scatter in observed d/D, with some pits too shallow to measure reliably. The range of preservation states observed for both pits and troughs is consistent with slow but persistent degradation on the surface of this (and perhaps other) small primitive planetesimal(s) in the Kuiper Belt by agents such as micrometeorite bombardment or volatile loss, indicating that degradation does indeed occur on such bodies. Arrokoth pits could also be related to circular depressions on comet 9P/Tempel (though comparisons of surface features on Arrokoth and comets are intriguing they are limited by resolution differences and the evolved state of cometary surfaces). Two of the curvilinear troughs occur along the terminator of the Large Lobe. One trough is a shallow depression devoid of resolvable structures, the other features several linear scarps a few 10s of meters high, suggesting that coherent failure can occur on the surfaces of small Kuiper Belt objects such as Arrokoth. Several of the deepest small pits are also

clustered within this walled trough, similar to tectonically associated pit chains on other planets. These pits and an obliquely viewed linear chain of elongate depressions remain the best candidates for endogenic features on Arrokoth. Subtle undulations and linear features no more than a few 10's of meters in amplitude (and even a few candidate positive relief features) are also evident in the terminator regions, indicating that the long-term evolution of this body may have been complex. https://doi.org/10.1016/j.icarus.2020.113834

Other Publications:

• Title: “SCExAO/MEC and CHARIS Discovery of a Low Mass, 6 AU-Separation Companion to HIP 109427 using Stochastic Speckle Discrimination and High-Contrast Spectroscopy” Authors: : Sarah Steiger, Thayne Currie (SSA/USRA), Timothy D. Brandt, Olivier Guyon, Masayuki Kuzuhara, Jeffrey Chilcote, Tyler D. Groff, Julien Lozi, Alexander B. Walter, Neelay Fruitwala, John I. Bailey III, Nicholas Zobrist, Noah Swimmer, Isabel Lipartito, Jennifer Pearl Smith, Clint Bockstiegel, Seth R. Meeker, Gregoire Coiffard, Rupert Dodkins, Paul Szypryt, Kristina K. Davis, Miguel Daal, Bruce Bumble, Sebastien Vievard, Ananya Sahoo, Vincent Deo, Nemanja Jovanovic, Frantz Martinache, Motohide Tamura, N. Jeremy Kasdin, Benjamin A. Mazin --- Short Abstract: We report the direct imaging discovery of a low-mass companion to the nearby accelerating A star, HIP 109427, with the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument coupled with the MKID Exoplanet Camera (MEC) and CHARIS integral field spectrograph. CHARIS data reduced with reference star PSF subtraction yield 1.1-2.4 μm spectra. MEC reveals the companion in Y and J band at a comparable signal-to-noise ratio using stochastic speckle discrimination, with no PSF subtraction techniques. Combined with complementary follow-up Lp photometry from Keck/NIRC2, the SCExAO data favors a spectral type, effective temperature, and luminosity of M4-M5.5, 3000-3200 K, and log10(L/L⊙)=−2.28+0.04−0.04, respectively. Relative astrometry of HIP 109427 B from SCExAO/CHARIS and Keck/NIRC2, and complementary Gaia-Hipparcos absolute astrometry of the primary favor a semimajor axis of 6.55+3.0−0.48 au, an eccentricity of 0.54+0.28−0.15, an inclination of 66.7+8.5−14 degrees, and a dynamical mass of 0.280+0.18−0.059 M⊙. This work shows the potential for extreme AO systems to utilize speckle statistics in addition to widely-used post-processing methods to directly image faint companions to nearby stars near the telescope diffraction limit. https://arxiv.org/abs/2103.06898 o Significance: This work shows the potential for high-contrast imaging systems on the ground and in space to utilize speckle statistics in addition to widely-used post-processing methods to directly image faint companions to nearby stars near the telescope diffraction limit.

• Title: Spatial linear dark field control on Subaru/SCExAO Authors: A Miller, K. L.; Bos, S. P.; Lozi, J.; Guyon, O.; Doelman, D. S.; Vievard, S.; Sahoo, A.; Deo, V.; Jovanovic, N.; Martinache, F.; Snik, F.; Currie, T(SSA/USRA). – Short Abstract: This work marks the first deployment of spatial LDFC on an active high-contrast imaging instrument. Our SCExAO testbed results show that the combination of the APvAPP with LDFC provides a powerful new focal plane wavefront sensing technique by which high-contrast imaging systems can maintain high contrast during long observations. This conclusion is further supported by a noise analysis of LDFC’s performance with the APvAPP in simulation. https://doi.org/10.1051/0004-6361/202039583

• Title: The Co Dust of Comet C/2013 US10 (Catalina): A Window into Carbon in the Solar System. Authors: Charles E. Woodward, Diane H. Wooden (SST), David E. Harker3, Michael S. P. Kelley, Ray W. Russell and Daryl L. Kim --- Short Abstract: Comet C/2013 US10 (Catalina) was a dynamically new Oort cloud comet whose apparition presented a favorable geometry for observations near close-Earth approach ( 0.93 au) at heliocentric distances 2 au when insolation and sublimation of volatiles drive maximum activity. Here we present mid-infrared 6.0 λ(μm) 40 spectrophotometric observations at two temporal epochs from NASA's Stratospheric Observatory for Infrared Astronomy and the NASA Infrared Telescope Facility that yield an inventory of the refractory materials and their physical characteristics through thermal modeling analysis. The grain composition is dominated by dark dust grains (modeled as amorphous carbon) with a silicate-to-carbon ratio 0.9, little crystalline stoichiometry (no distinct 11.2 μm feature attributed to Mg-rich crystalline olivine), and the submicron grain-size distribution peaking at 0.6 μm. The 10 μm

silicate feature was weak, ≈12.8% ± 0.1% above the local continuum, and the bolometric grain albedo was low ( 14%). Comet C/2013 US10 (Catalina) is a carbon-rich object. This material, which is well represented by the optical constants of amorphous carbon, is similar to the material that darkens and reddens the surface of comet 67P/Churyumov– Gerasimenko. We argue this material is endemic to the nuclei of comets, synthesizing results from the study of Stardust samples, interplanetary dust particle investigations, and micrometeoritic analyses. The atomic carbon-to-silicate ratio of comet C/2013 US10 (Catalina) and other comets joins a growing body of evidence suggesting the existence of a C/Si gradient in the primitive solar system, providing new insight into planetesimal formation and the distribution of isotopic and compositional gradients extant today. https://doi.org/10.3847/PSJ/abca3e

Publication Journal/Web link Authors: Helle L. Skjetnea, Kelsi N. Singer, Brain M. Hynek, Katie L. Title: Morphological comparison of Knight, Paul M. Schenk, Cathy B.Olkin, Oliver, L. White(SST), Tanguy blocks in chaos terrains on Pluto, Bertrand (SST/USRA), Kirby D. Runyon, William B. McKinnon, Jeffrey Europa, and Mars Moore (SST)., S Alan Stern, Harold A. Weaver, Lesie, A. Young, Kim Publication: Elsevier: ICARUS: Ennico (SSA) Volume 356 Link: https://doi.org/10.1016/j.icarus.2020.11 3866 Publication Date: 03/01/2021 Authors: Dale P. Cruikshank(SSA), Cristina M. Dalle Ore (SSA/SETI), Title: Cryovolcanic flooding in Viking Francesca Scipioni (SSA/SETI), Ross A. Beyer(SST/SETI), Oliver L. Terra on Pluto White (SST/SETI), Jeffrey M. Moore (SST), William M. Grundy, Bernard Publication: Elsevier: ICARUS: Schmitt, Kirby D. Runyon, James T. Keane, Stuart J. Robbins, S. Alan Volume 356 Stern, Tanguy Bertrand (SST/USRA), Chloe B. Beddingfield Link: (SST/SETI), Catherine B. Olkin, Leslie A. Young, Harold A. Weaver, https://doi.org/10.1016/j.icarus.2020.11 Kimberly Ennico (SSA) 3786 Publication Date: 03/01/2021

Authors: L.R. Gabasova, B. Schmitt, W. Grundy, T. Bertrand Title: Global compositional cartography (SST/USRA), C. B. Olkin, J.R. Spencer, L. A. Young, K. Ennico (SSA), of Pluto from intensity-based H. A. Weaver, S. A. Stern and the New Horizons Composition Team registration of LEISA data Publication: Elsevier: ICARUS: Volume 356 Link: https://doi.org/10.1016/j.icarus.2020.11 3833 Publication Date: 03/01/2021 Authors: S. A. Stern, O. L. White(SST/SETI), P. J. McGovern, J. T. Title: Pluto’s Far Side Keane (NASA JPL), J. W. Conrad, C. J. Bierson, T. R. Lauer, C. B. Olkin, Publication: Elsevier: ICARUS: L. A. Young, P. M. Schenk, J.M. Moore(SST), H. A. Weaver, K. D. Volume 356 Runyon, K. Ennico (SSA), The New Horizons Team. Link: https://doi.org/10.1016/j.icarus.2020.11 3805 Publication Date: 03/01/2021 Authors: Briley L. Lewis, John A. Stansberry, Bryan J. Holler, William M. Title: Distribution and energy balance Grundy, Bernard Schmitt, Sylvia Protopapa, Carey Lisse, S. Alan Stern, of Pluto’s nitrogen ice, as seen by New Leslie Young, Harold A. Weaver, Catherine Olkin, Kimberly Ennico Horizons in 2015 (SSA), New Horizons Science Team Publication: Elsevier: ICARUS: Volume 356 Link: https://doi.org/10.1016/j.icarus.2020.11 3633 Publication Date: 03/01/2021

Authors: P.E. Johnson, L. A. Young, S. Protopapa, B. Schmidt, L. R. Title: Modeling Pluto’s minimum Gabasova, B. L. Lewis, J. A. Stansberry, K. E. Mandt, O. L. White pressure: Implications for haze (SST/SETI) production Publication: Elsevier: ICARUS: Volume 356 Link: https://doi.org/10.1016/j.icarus.2020.11 4070 Publication Date: 03/01/2021 Authors: Seeger, Ho Chit Siu, Chris Stockdale, Daisuke Suzuki, Title: Haze in Pluto's atmosphere: Thanawuth Thanathibodee, Trudy Tilleman, Paul J. Tristram, William D. Results from SOFIA and ground-based Vacca, Jeffrey Van Cleve (SSA/SETI), Carolle Varughese, Luke W. observations of the 2015 June 29 Pluto Weisenbach, Elizabeth Widen, Manuel Wiedemann (PX) [DLR] occultation Publication: Elsevier: ICARUS: Volume 356 Link: https://doi.org/10.1016/j.icarus.2019.11 3572 Publication Date: 03/01/2021 Authors: C.M. Lisse, A. Young, D. P. Cruikshank (SSA), S. A. Title: On the Origin & Thermal Stability Sandford (S), B. Schmitt, S. A. \Stern, H. A. Weaver, O. Umurhan of Arrokoth’s and Pluto’s Ices (SST/SETI), Y.J. Pendelton(SST), J. T. Keane, G. R. Gladstone, J. M. Publication: Elsevier: ICARUS: Parker, R. P. Binzel, A. M. Earle, M. Hornayi, M. R. El-Maarry, A. F. Volume 356 Cheng, J. M. Moore(SST), W. B. McKinnon, W.M. Gundy, J. H. Link: Kavelaars, L. R. Linscott, W. Lyra, B. L. Lewis, D. T. Britt, J. R. Spencer, https://doi.org/10.1016/j.icarus.2020.11 C. B. Olkin, R. L. McNutt, H. A. Elliot, N. Dello-Russo, J. K. Steckloff, M. 4072 Neveu, O Mousis Publication Date: 03/01/2021

Authors: Stuart J.Robbins, Paul M.Schenk, Jamie D.Riggs, Alex Title: Depths of Pluto’s and Charon’s H.Parker, Veronica J.Bray, Chloe B.Beddingfield (SST/SETI), Ross craters, and their simple-to-complex A.Beyer(SST/SETI), Anne J.Verbiscer, RichardBinzel, Kirby D.Runyon transition Publication: Elsevier: ICARUS: Volume 356 Link: https://doi.org/10.1016/j.icarus.2020.11 3902 Publication Date: 03/01/2021 Authors: Sihe Chen, Eliot F.Young, Leslie A.Young, Tanguy Bertrand Title: Global climate model occultation (SST/USRA), François Forget, Yuk L.Yunga lightcurves tested by August 2018 ground-based stellar occultation Publication: Elsevier: ICARUS: Volume 356 Link: https://doi.org/10.1016/j.icarus.2020.11 3976 Publication Date: 03/01/2021 Authors: Adam D.Jacobs, Michael E.Summers, Andrew F.Cheng, G. Title: LORRI observations of waves in Randall Gladstone, Carey M.Lisse, W. Dean Pesnell, Tanguy Bertrand Pluto’s atmosphere (SST/SETI), Darrell F.Strobel, Leslie A.Young, Harold A.Weaver, Joshua Publication: Elsevier: ICARUS: Kammer, Peter Gao Volume 356 Link: https://doi.org/10.1016/j.icarus.2020.11 3825 Publication Date: 03/01/2021

Authors: Jason D.Hofgartner, Bonnie J.Buratti, Susan D.Benecchi, Title: Photometry of Kuiper belt object Ross A.Beyer (SST/SETI), Andrew Cheng, James T.Keane, Tod Arrokoth from New Horizons LORRI R.Lauer, Catherine B.Olkin, Joel W.Parker, Kelsi N.Singer, John Publication: Elsevier: ICARUS: R.Spencer, S. AlanStern, Anne J.Verbiscer, Harold A.Weaver, New Volume 356 Horizons Geology and Geophysics Team, New Horizons LORRI Team Link: https://doi.org/10.1016/j.icarus.2020.11 3723 Publication Date: 03/01/2021 Authors: Paul Schenk, Kelsi Singer, Ross Beyer (SST/SETI), Chloe Title: Origin of pits and troughs and Beddingfield (SST/SETI), Stuart J.Robbins, William B.McKinnon, Tod degradation on a small primitive R.Lauer, Anne J.Verbiscer, James.T.Keane, Rajani D.Dhingra, Jeffrey planetesimal in the Kuiper Belt: high- Moore (SST), Joel W.Parker, CathyOlkin, John Spencer, HalWeaver, S. resolution topography of (486958) AlanStern Arrokoth (aka 2014 MU69) from New Horizons Publication: Elsevier: ICARUS: Volume 356 Link: https://doi.org/10.1016/j.icarus.2020.11 3834 Publication Date: 03/01/2021 Authors: Sarah Steiger, Thayne Currie(SSA/USRA), Timothy D. Title: “SCExAO/MEC and CHARIS Brandt, Olivier Guyon, Masayuki Kuzuhara, Jeffrey Chilcote, Tyler D. Discovery of a Low Mass, 6 AU- Groff, Julien Lozi, Alexander B. Walter, Neelay Fruitwala, John I. Bailey Separation Companion to HIP 109427 III, Nicholas Zobrist, Noah Swimmer, Isabel Lipartito, Jennifer Pearl using Stochastic Speckle Smith, Clint Bockstiegel, Seth R. Meeker, Gregoire Coiffard, Rupert Discrimination and High-Contrast Dodkins, Paul Szypryt, Kristina K. Davis, Miguel Daal, Bruce Bumble, Spectroscopy” Sebastien Vievard, Ananya Sahoo, Vincent Deo, Nemanja Jovanovic, Publication: The Astrophysics Journal Frantz Martinache, Motohide Tamura, N. Jeremy Kasdin, Benjamin A. (ApJ) Mazin Link: https://arxiv.org/abs/2103.06898 Submission Date: 03/11/2021 Authors: A Miller, K. L.; Bos, S. P.; Lozi, J.; Guyon, O.; Doelman, D. S.; Title: Spatial linear dark field control on Vievard, S.; Sahoo, A.; Deo, V.; Jovanovic, N.; Martinache, F.; Snik, F.; Subaru/SCExAO. Maintaining high Currie, T(SSA/USRA). contrast with a vAPP coronagraph Publication: Astronomy & Astrophysics, Volume 646, id.A145, 12 pp. Link: 10.1051/0004-6361/202039583 Publication Date: 02/2021 Authors: Charles E. Woodward, Diane H. Wooden (SST), David E. Title: The Co Dust of Comet C/2013 Harker3, Michael S. P. Kelley, Ray W. Russell and Daryl L. Kim US10 (Catalina): A Window into Carbon in the Solar System Publication: The Planetary Science Journal, Volume 2, Number 1

Link: https://doi.org/10.3847/PSJ/abca3e Publication Date: Published 2021 February 8

SCIENCE COMMUNICATION STORIES

• Thayne Currie (SSA/USRA) led the discovery of the very low-mass substellar companion HD 33632 Ab with the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system at the Subaru Telescope in Hawaii. This result is

proof-of-concept of a new strategy to search for imageable planets: targeting stars showing evidence for unseen planets from the astrometric accelerations they induces on their host stars, instead of conducting blind imaging survey as has been previously done. This work is described in a recently published peer-reviewed paper – Currie, Brandt, & Kuzuhara et al. 2020, ApJL, 904, L25 – and accompanying press release: https://subarutelescope.org/en/results/2020/12/10/2918.html .

• NASA published a web feature about the new selected Pioneer mission, Pandora (https://www.nasa.gov/feature/goddard/2021/pandora-mission-would-expand-nasa-s-capabilities-in-probing-alien- worlds). The article quotes Jessie Dotson (SS), Pandora’s Deputy Principal Investigator. Tom Greene (SSA) and Christina Hedges (SSA/BAERI) are Co-Investigators on the mission.

• Janice Bishop (SSX/SETI) moderated this month’s public SETI Talks on Wednesday March 24 at 7 PM Pacific, https://www.seti.org/seti-talks. This month’s Talk is entitled, “The search for Life on Mars with Perseverance”. Recordings are posted to the SETI Talks YouTube channel

• Alfonso Davila (SSX) gave a talk at the Spring 2021 Translational Biotechnology Seminar Series of the University of Southern California, on March 17th. The title of the talk was “The search for a second genesis of life on the solar system”. (https://dtg.usc.edu/site/index.php/biotechnology/events/).

• Melissa Kirven (SSX) participated in am Artemis Moon Pod Essay Contest event in which K-12 students asked questions which were answered by a current NASA Astronaut and NASA scientists. https://www.futureengineers.org/artemismoonpodessay

OTHER HIGHLIGHTS AND NEWS

• Thayne Currie (SSA/USRA) was selected as the lead author for the review chapter entitled “Direct Imaging and Spectroscopy of Extrasolar Planets” for Protostars and Planets VII, which will be held in Kyoto, Japan on March 21-27 2022. The Protostars and Planets conference series provides an overview of the state of our knowledge in the fields of star and planet formation. This will be the first major update of the exoplanet direct imaging field for Protostars and Planets in over a decade.

• Thayne Currie (SSA/USRA), Eugene Pluzhnik (SSA/BAERI), and Ruslan Belikov (SSA) led the successful completion of Milestone 1 for NASA-Strategic Astrophysics Technology project entitled “Linear Wavefront Control”, using the Ames Coronagraphic Experiment testbed. This program focuses on developing Linear Dark Field Control (LDFC), a new wavefront control method to sustain deep-contrast regions around a star to detect light from faint exoplanets. They successfully demonstrated a closed-loop implementation of LDFC at contrasts relevant for imaging exoplanets in reflected light. LDFC could improve NASA’s capability to image solar system-like planets in reflected light with upcoming missions like Roman-CGI, HabEx, or LUVOIR. Their work is described in a recently published peer- reviewed paper: Currie, Pluzhnik, and Guyon et al. 2020, PASP, 132, 104502. https://doi.org/10.1088/1538- 3873/aba9ad

SPACE BIOSCIENCES DIVISION HIGHLIGHTS Code S Weekly Report

Date: 25 March 2021 Division: SC

SIGNIFICANT ANNOUNCEMENTS

• Twelve Biology of Spaceflight Papers Represent Groundbreaking Work

Last November, a coordinated package of 29 scientific papers on the biology of spaceflight was published in five Cell Press journals and appeared online in Cell, Cell Reports, iScience, Cell Systems, and Patterns. Among the groundbreaking work published in the Cell Press package are 12 scientific papers authored by scientists in the NASA Ames Research Center Science Directorate. Coordination of the publication of these papers was led by Drs. Afshin Beheshti (NASA Ames Research Center), Susan Bailey (Colorado State University), and Christopher Mason (Weill Cornell Medicine). Over 200 news articles were published worldwide on social media, and in newspapers and science journals. Twelve plain language summaries of these articles for the science community are now available on the NASA website.

UPCOMING MEETINGS/EVENTS/CONFERENCES

Date Name Who and what (location)

March 31, COV-IRT 3rd COV-IRT 3rd Symposium, 9:30 AM – 5:30 PM (CST) 2021 Symposium Registration is free: https://tinyurl.com/ze4kank6 Visit http://www.cov-irt.org/symposium-3 for more information.

AWARDS AND RECOGNITIONS

SC Division Awarded Three Ames Research Innovation Award (ARIA) The Space Biosciences division was awarded three ARIAs last Thursday, March 18. Please find below the POCs and proposal title:

• Dr. Egle Cekanaviciute - Human Neuroimmune Responses to Simulated Spaceflight Stressors

• Dr. Sigrid Reinsch - RadBREAD: Radiation Biology Research at an Elevated Altitude through Dosimetry

• Dr. Marianne B. Sowa - Neuro-signatures: Early developmental epigenomic, transcriptomic, and proteomic alterations during spaceflight in Drosophila melanogaster

• Viktor Stolc Awarded awarded the 2021 NASA Ames H. Julian Allen Award Dr. Viktor Stolc received the 2021 H. Julian Allen Award for his paper, "Global Identification of Human Transcribed Sequences with Genome Tiling Arrays,” published in Science (Science 306: 2242-2246). The H. Julian Allen Award was established in 1969 to annually recognize a scientific or engineering paper of outstanding technical merit and significance. The winning author receives a plaque and is required to give a lecture to the Center.

To make this advance in biology, great technological advancements were required to analyze genetic material. Deciphering the complex code of the human genome has revolutionized our understanding of life and our approach to medicine. This paper is a seminal report in human genetics, relying on innovative technologies for whole genome analysis developed by Dr. Viktor Stolc. Since its initial publication in Science, a leading journal in our field (2019 Impact Factor 41.845), this publication has been cited over 1,200 times.

As described by Dr. Maurice Ohayon of Stanford University, “This work has significantly impacted genomic research and has enabled the discovery of previously un-described functions of non-coding RNA”. This work advanced microarray technology by both reducing costs and increasing production throughput. Although developments in genomics research continue at a rapid pace and have drifted from microarray, this work still garners new citations, emphasizing the groundbreaking nature of the work.

PROJECT MILESTONES

• GeneLab Releases Three New Datasets

GeneLab curated and released three additional datasets, bringing the total available number spaceflight and spaceflight relevant datasets to 312. These datasets include a transcriptional analysis of human muscle under different loading regimes (Molecular Transducers of Human Skeletal Muscle Remodeling under Different Loading States), a transcriptional analysis of WT and UPR-defective Arabidopsis seedlings flown on the ISS (Relevance of Unfolded Protein Response to Spaceflight-Induced Transcriptional Reprogramming in Arabidopsis), and a transcriptional analysis of human intestinal epithelial cells exposed to Salmonella typhimurium (Evaluating the effect of spaceflight on the host- pathogen interaction between human intestinal epithelial cells and Salmonella Typhimurium). Now that these datasets are publicly available, they can be reanalyzed in the context of other datasets for the generation of new hypothesis and knowledge. https://genelab-data.ndc.nasa.gov/genelab/accession/GLDS-321/ https://genelab-data.ndc.nasa.gov/genelab/accession/GLDS-323/ https://genelab-data.ndc.nasa.gov/genelab/accession/GLDS-354/

PUBLICATIONS

Publication Journal/Web link

Spaceflight Promotes Branching of Neurons and Accumulation https://pubmed.ncbi.nlm.nih.gov/33659873/ of Neural Waste Products

Abstract

Extended space travel poses health risks to the human nervous system. In a newly published study, scientists using the model nematode Caenorhabditis elegans as a human surrogate investigated how spaceflight affects adult neurons. They examined the morphology of neurons responsible for sensing harshtouch, cold, and posture. After 5 days of adulthood on the International Space Station (ISS) animals exhibited hyperbranching in touch receptor neurons. Spaceflight also appears to promote a remarkable accumulation of neuronal-derived waste in the surrounding tissues, suggesting impairment in the breakdown of cellular waste released from neurons. These data reveal that spaceflight can significantly affect adult neuronal morphology and clearance of neuronal “trash”, highlighting

Illustration showing how spaceflight promotes Disorganization defects in sensory neurons

New Species from the Bacterial Genus, Methylobacterium, https://www.frontiersin.org/articles/10.3389/ Isolated from ISS fmicb.2021.639396/full

Abstract

NASA has been performing routine microbial monitoring of the ISS surface, air, and water for the past 20 years. Creating a catalog of the different microbial isolates found on the ISS is essential for NASA to monitor the indoor environment to safeguard astronaut health. A novel species named Methylobacterium ajmalii was isolated from different locations within the ISS and was characterized in a recent paper published on Mar 15, 2021. Methylobacterium species are ubiquitous on Earth and found in various habitats, including air, soil, and fresh water, and can be found either in free-form or associated with plant tissues. Within the family Methylobacteriaceae, this genus, Methylobacterium, is abundant and contains 67 validly described species. Whether this species of Methylobacterium has a significant function in space or human health remains to be investigated.

SCIENCE COMMUNICATION STORIES

• N/A

OTHER HIGHLIGHTS AND NEWS

• Dr. Xiao-Hong Lu of LSU Health Shreveport is one of the newest class of Space Biology researchers awarded a grant from BPS to develop a novel genetic engineering technology to evaluate the impact of space radiation on the human brain. The announcement of his NASA grant has received local media coverage on the LSU Health Shreveport school website and in the Shreveport Times. Dr. Xiao-Hong Lu was also interviewed by local TV news channel KTBS3, but the interview has not aired yet.

• BPS Division Science Activation and Citizen Science audit has been completed by Egle Cekanaviciute (NASA ARC) and Gamble Gilbertson (NASA HQ) and presented to Craig Kundrot and Diane Malarik. It summarizes all ongoing science activation and citizen science projects at ARC, JPL, MSFC, GRC and KSC, and provides suggestions for developing new projects. As a follow up, a BPS-wide solicitation for new science activation and citizen science projects has been opened.

POC: Egle Cekanaviciute, Code SCR

• SCR scientist Egle Cekanaviciute gave a plenary presentation “Neuroimmune Responses to Space Radiation” at Open Readings conference/seminar series held by Vilnius University in Vilnius, Lithuania (www.openreadings.eu).

POC: Egle Cekanaviciute, Code SCR

• Two NASA Ames Scientists Gave Invited talks for the Association of Biomolecular Resource Facilities (ABRF) 2021 Virtual Meeting For A Plenary Session on CORES IN SPACE: Shared Resources in Orbit Drs. Afshin Beheshti and Parag Vaishampayan were invited to speak at a special plenary session on Cores In Space for the Association of Biomolecular Resource Facilities 2021 Virtual Meeting. The meeting was from March 7th – 11th. The ABRF meeting typically covers topics within or in the support of resource and research biotechnology laboratories. This special plenary session was organized to discuss the how experiments are done in the International Space Station. The following description was in the program schedule for this session: “The International Space Station (ISS) has served as a site of collaborative research for nearly two decades. In many ways, the station can be seen to play the role of a core facility - a center of unique/expensive equipment researchers cannot have on their own and where experts perform those experiments for a broad variety of research projects across a wide area of questions surrounding biological systems and human health. This session will focus on how NASA has addressed the unique challenges associated with managing such a core facility, with possible lessons for their terrestrial brethren.” Dr. Vaishampayan discussed how different experiments are conducted on the ISS and also different ways scientists may be able to conduct experiments on the ISS (i.e. applying for funding mechanisms through NASA). Dr. Beheshti also discussed experiments on the ISS and mainly focused on how omics data is produced and how GeneLab is involved with this process. In addition, he highlighted their recent publications from the Analysis Working Group (AWG) published in Cell. Approximately 140 people attended this virtual plenary session. Meeting information can be found here: https://web.cvent.com/event/8eb4a085-b3c5-464a-ba49-023f033a7ee4/summary

POC: Afshin Beheshti