Planetary Science Institute

JUPITER & ITS MOONS • PaGe 6 SATURN’S SATELLITES • PAGE 8 INVESTIGATING MARS ICE • PAGE 9 DAWN GOES DARK • PAGE 10

aNNuaL rePorT 2018 Dedicated to Solar System exploration, PSI scientists are involved in NASA and international missions, fieldwork around the world, education, and public outreach.

PLANETARY SCIENCE INSTITUTE

The Planetary Science Institute is a private, nonprofit 501(c)(3) corporation dedicated to Solar System exploration. It is headquartered in Tucson, Arizona, where it was founded in 1972.

PSI scientists are involved in NASA and international missions, the study of Mars and other planets, the Moon, asteroids, comets, interplanetary dust, impact physics, the origin of the Solar System, extra-solar planet formation, dynamic evolution of planetary systems, the rise of life, and other areas of research. They conduct fieldwork on all continents around the world. They also are actively involved in science education and public outreach through school programs, children’s books, popular science books and art.

PSI scientists and educators are based in 25 states and the District of Columbia, and work from various international locations. . PSI Board of Trustees

Tim Hunter, M.D., Chair Scott Fouse Erin Neal Candace Kohl, Ph.D., Vice Chair William K. Hartmann, Ph.D. Mark V. Sykes, Ph.D., J.D. Michael J.S. Belton, Ph.D. Pamela Melroy

On the cover: “Somewhere, Sometime on Mars” Acrylic painting by William K. Hartmann, co-founder and Senior Scientist Emeritus at the Planetary Science Institute.

This painting was made at Arches National Park, transforming a view of South Window Arch into a future Martian scene by deleting vegetation, altering sky color, and adding a foreground impact crater typical of newly formed impacts being discovered on Mars.

Formation of arches at the National Park involved the dissolving of ancient soluble deposits in an ancient inland sea, and it seems plausible that similar processes could have happened in ancient, lake-filled craters on Mars.

Planetary Science Institute | 1700 E. Fort Lowell, Suite 106 | Tucson, Arizona 85719-2395 | Phone 520-622-6300 | Fax 520-622-8060 | www.psi.edu 2 NOTE FROM THE DIRECTOR

PSI was honored this year by the generous donation of $40,000 to the Pierazzo Memorial Fund by Senior Scientist Michelle Thomsen. This fund supports the Pierazzo International Student Travel Awards, named in honor our late Senior Scientist Betty Pierazzo. They provide $2,000 to a graduate student at a U.S. institution to travel to a planetary-related meeting outside of the U.S., and another $2,000 to a graduate student at a non-U.S. institution to travel to a planetary- related meeting within the U.S. Dr. Thomsen’s gift now makes these awards self-sustainable and a permanent part of what PSI does as electrical grids. These new structures can have a significant an institution. impact on how we prepare for and mitigate these potentially very The Dawn mission came to an end this year, going silent as it disruptive events. orbited the dwarf planet Ceres, gathering the highest resolution Senior Scientist Faith Vilas was awarded the 2018 Harold images yet of the cryovolcanic dome in Occator crater (dramatically Masursky Award for meritorious service to planetary science. white against the dark background of Ceres). High resolution One of the many things for which she was honored was her gamma-ray and neutron detector data were obtained, further teasing insuring the integrity of the Discovery mission selection process out the elemental composition of Ceres. There are years of analysis in the aftermath of the 9/11 attack, which occurred during rehearsal ahead. More than 24 scientists now at PSI have worked on Dawn. for the Dawn site visit at Orbital Sciences near Dulles Airport. I was Basic research can be critical to the design of missions. Studying there, and her taking charge of a situation in chaos to shut things the scattering properties of water ice at very low phase angles, Senior down while figuring out in real time how to restart the process Scientist Robert Nelson and his group determined that the surface later in a way that was fair was a sight to behold. of Jupiter’s icy Europa would have a very low density, comparable to Other PSI scientists being recognized this year include Senior freshly fallen snow. The planned Europa Lander may need to have Scientist Darby Dyar, who received the Shoemaker Distinguished large-area landing pads or a very long antenna! Science Medal from NASA’s Solar System Exploration Research Science means being open about changing our minds with new Virtual Institute for a career of significant contributions to laboratory information. Senior Scientist Roger Clark came up with a new studies. Senior Scientist David Grinspoon was awarded the method for remotely measuring isotopic ratios of water and carbon Shoemaker Memorial Award for his lifework including the planetary- dioxide and found that the water in Saturn’s rings and satellites is scale dilemmas we face as a species. Senior Scientist Amara Graps unexpectedly like water on the Earth, but that its moon Phoebe’s received the Europlanet Prize for Public Engagement with Planetary water is very unusual and may indicate an origin in the outermost Science for her extensive activities in the Baltic states. Finally, Senior reaches of the Solar System. This motivates some rethinking of Scientist Candice Hansen was awarded NASA’s Outstanding Public models of Solar System formation which predict very different Leadership Medal for JunoCam, which has given us images of Jupiter isotopic ratios of water at Earth and Saturn. that have been startling in their beauty, revealing complex storms We embrace Solar Systems around other stars, where Senior and atmospheric processes never before seen. Scientist Amy Barr Mlinar identified two planets orbiting PSI lost a great friend, mentor and benefactor this year. Michael TRAPPIST-1 as potentially habitable. The Earth is also a planet, J.S. Belton was a world-renowned expert on comets, a broad thinker and Senior Scientist Jeff Kargel studies glaciation on Mars and in and pianist. He was generous with his ideas, and inspired many the Himalayas. His research has reduced the hazards to villages young scientists over the years, including myself. As a member in Nepal of high-altitude lakes and avalanches, for which he of the PSI Board of Trustees, he played an important role in the was awarded the Nepal Geographical Society Honorary Life generation of our strategic plan. Mike and his wife, Anna Don, Membership. Finally, the Sun is part of the Solar System. established a fund to support a series of Belton Symposiums, which Associate Research Scientist Elizabeth Jensen made a major will span at least the next 20 years and shape the future of comet discovery of trailing components of a Coronal Mass Ejection. nucleus studies. He will be deeply missed. CMEs can cause problems with satellites orbiting the Earth and — Mark V. Sykes 3 PSI scientists garnered many prestigious awards during 2018

Darby Dyar Honored for Lunar/Asteroid Science Contributions Senior Scientist Darby Dyar received the Eugene Shoemaker Distinguished Science Medal from NASA’s Solar System Exploration Research Virtual Institute (SSERVI) for her significant contributions David Grinspoon Honored for Life and Work to the field of lunar and/or asteroid science throughout the course of her scientific career. Senior Scientist David Grinspoon received the 2018 Eugene Shoemaker Memorial Award Oct. 2 at Arizona State University. SSERVI said: “Dyar has had a distinguished career spanning more than 30 years in which she authored 242 peer reviewed publications. The award, presented by ASU’s Beyond Center for Fundamental Her areas of expertise are numerous, including optical mineralogy, Concepts in Science, is given annually to a leading scientist in honor crystal chemistry, and numerous spectroscopic techniques. In of his or her life and work. It is named for Shoemaker, who is known recent years she has also revolutionized the use of machine learning for pioneering research with his wife, Carolyn, in the field of asteroid techniques in the analysis and interpretation of X-ray absorption and comet impacts. spectra. The careful laboratory work and model development that she has led throughout her career have enabled thousands of other Candace Hansen Receives Medal for JunoCam Work papers that have utilized the data she has generated; her work will Senior Scientist Candice Hansen received NASA’s Outstanding prove to be substantially more important than any single mission. Public Leadership Medal for her work on the JunoCam camera that Without Dyar in our field for the last 30 years, our understanding of is taking amazing images of Jupiter. planetary processes and the interpretation of various mission data Hansen is a Co-Investigator on the Juno mission now orbiting would be much poorer.” Jupiter, responsible for the development and operation of the Amara Graps Recognized for Work in Planetary Science JunoCam outreach camera that engages the public in planning Communication to General Public images of Jupiter. Amateur astronomers supply images from their backyard telescopes for planning. Citizen scientists and artists Senior Scientist Amara Graps was awarded the 2018 Europlanet download raw images and then contribute their own processed Prize for Public Engagement with Planetary Science for her versions to the JunoCam online gallery (https://www.missionjuno. far-reaching work to inspire and promote space activities in the swri.edu/junocam/processing). Baltic region within the scientific and industrial communities, in education and in wider society. The NASA Outstanding Public Leadership medal is awarded to non-government employees for notable leadership accomplishments The prize recognizes and honors outstanding communication that have significantly influenced the NASA mission. This includes to the general public in planetary science by an individual or sustained leadership and exceptionally high-impact leadership an institution. It is awarded to individuals or groups who have achievements that demonstrate the individual’s effectiveness in developed innovative practices in planetary science communication, advancing the agency’s goals and image in present and future terms. and whose efforts are contributing significantly to a wider public engagement with, and enthusiasm for, planetary science. Jeff Kargel Recognized for Himalayan Work Graps, based in Riga, Latvia, was recognized for her efforts to bridge Senior Scientist Jeff Kargel was awarded the Nepal Geographical gaps that exist that prevent the general public from understanding, Society Honorary Life Membership on the basis of his work on and embracing, developments in planetary science. She is the founder Himalayan natural hazards and geomorphology. of the not-for-profit organization, Baltics in Space. Graps’ work That work included applied science and science in support of with Baltics in Space supported the successful European Planetary humanitarian activity, including his response to the 2015 earthquake Science Congress (EPSC) 2017, sponsored by PSI, which took place in Nepal, his research that led to the lowering of Imja Lake to reduce in Riga Sept. 17-22, 2017. The event made a significant contribution its hazard, and work regarding several other natural disaster events to raising the profile of space in Latvia and the Baltics with audiences and hazards. The work for which he was recognized also included ranging from members of Parliament and Ministries, business, the the basic science examination of glacial lake accelerated melting media, educators and schools. 4 of glaciers, the mass balance of Himalayan glaciers, and the role of AWARD-WINNING SCIENTISTS lithology and bedrock geology in controlling landslides. From left to right: Darby Dyar (photo credit: Molly McCanta); Amara Graps; CandIce Hansen; and Jeff Kargel Faith Vilas Receives Masursky Award for Meritorious Service The Division for Planetary Sciences (DPS) of the American “As Chair of the DPS, Vilas played a key role in establishing the Carl Astronomical Society gave the 2018 Harold Masursky Award for Sagan Medal, which was the first major statement in support of the Meritorious Service to Planetary Science to Faith Vilas. Vilas is importance of communicating our science with the public. She has the Deputy PI for SSERVI’s Toolbox for Research and Exploration mentored and inspired young people who have become well-known (TREX) team led by PSI’s Amanda Hendrix. figures in our profession, and others who have taken an apprecia- tion of our science into other careers. She has served on numerous “DPS awards the 2018 Harold Masursky Award for meritorious Academy and NASA panels. Her service to the field and to society service to planetary science to Faith Vilas. During a time of national has been exemplary.” duress following the chaos of the 9/11 attack, she insured the integrity of the Discovery program selection process. As the first The Harold Masursky Award for Meritorious Service to Planetary Chair of the NASA Small Bodies Assessment Group, she established Science was established by the DPS to recognize and honor individuals its operational practices and made it the viable entity that continues who have rendered outstanding service to planetary science and today,” the DPS citation said. exploration through engineering, managerial, programmatic, or public service activities.

2018 NASA GROUP ACHIEVEMENT HONOR AWARDS

A number of PSI scientists received 2018 NASA Honor Awards, Group Achievement Awards, including: • Bruce Barraclough, Cassini Plasma Spectrometer Team For significant science contributions by the Cassini Plasma Spectrometer team to the Cassini mission. • Roger Clark and Emily Joseph, Visual and Infrared Mapping Spectrometer Team For exceptional contributions to the Visual and Infrared Mapping Spectrometer Investigation during Cassini’s Solstice and Grand Finale Mission. • Candice Hansen, Juno Mission Re-Design Team For excellence in defining, assessing and implementing a major mission re-design resulting from remaining in a 53-day orbit. • Candice Hansen, JunoCam Imaging and Public Engagement Team For outstanding engagement of the public to participate in the acquisition and processing of raw images from JunoCam at Jupiter. • Candice Hansen and Amanda Hendrix, Ultraviolet Imaging Spectrograph Science Team For outstanding contributions to understanding the Saturn system using ultraviolet imaging and spectroscopy during Cassini’s Solstice and Grand Finale missions. • Amanda Hendrix, Cassini Project Science Team For exceptional achievement in maximizing the overall scientific success of the Cassini Solstice mission within project constraints, thus enabling unprecedented science return. • Charles Wood, Cassini Radar Science and Operations Team For exceptional Cassini Radar Team performance in the operations and analysis during Cassini’s Solstice Mission and Grand Finale resulting in unprecedented science return.

5 NASA’S JUNO MISSION LEARNING MORE ABOUT JUPITER and ITS MOONS

PSI scientists working on NASA’s Juno mission continue to learn more about Jupiter and its moons.

Large cyclones have been discovered clustered around Jupiter’s poles by NASA’s Juno spacecraft. The circumpolar cyclones were discovered on Juno’s first pass over Jupiter’s poles, and subsequent data has revealed how remarkably stable they are. The circumpolar cyclones ring a single cyclone at each pole.

Using visible images from NASA’s JunoCam camera headed by PSI Senior Scientist Candice Hansen, and infrared images obtained by the spacecraft’s Jovian Infrared Auroral Mapper (JIRAM), researchers found eight circumpolar cyclones arranged around a single northern polar cyclone and five circumpolar cyclones encircling a southern polar cyclone.

“Jupiter’s circumpolar cyclones are unique; the polar regions are unlike any of the other gas giants,” said Hansen, JunoCam instrument lead and Juno Co-Investigator. “The circumpolar cyclones in the north are as big as the continental United States. The cyclones in the south are even larger.

“And they are surprisingly stable. They are identifiable from one close pass to the next, with a 53-day separation, and they are in a very stable configuration – no new ones have spun up, no old ones have dissipated,” she said.

Wind speeds measured 580 miles from the center of these giant storms range from 100 mph to 220 mph, she said.

The study of two potential plume sites on Jupiter’s moon Europa has shown a lack of expected hotspot signatures, unlike Enceladus where plumes have a very clear and obvious temperature signature, research by PSI Senior Scientist Julie Rathbun shows.

“We searched through the available Galileo thermal data at the locations proposed as the sites of potential plumes. Reanalysis of temperature data from the Galileo mission does not show anything special in the locations where plumes have possibly been observed. There are no hotspot signatures at either of the sites,” Rathbun said. “This is surprising because the Enceladus plumes have a clear thermal signature at their site of origin, so this suggests that either the Europa plumes are very different, or the plumes are only occasional, or that they don’t exist, or that their thermal THIS PAGE: Europa Plume signature is too small to have been detected by current data.” This is an artist’s concept of a plume of water vapor thought to be ejected off the frigid, icy Plumes are jets of gas that are sent upward from a planet’s surface, similar to Old surface of the Jovian moon Europa. Faithful in Yellowstone National Park. For the gas to be shot upward, an energy Credit: NASA/ESA/K. Retherford/SWRI

6 source is needed. Generally, that energy source will also heat the surface around the plume source, like we see in Yellowstone with hotspots at the geysers and hot springs nearby. This is also what is seen on Enceladus, a hot region where the plumes erupt from Enceladus’ surface. The hot spots at Yellowstone and Enceladus are unmistakable and readily observed. The lack of a hotspot at Europa ABOVE LEFT: EUROPA SURFACE SWATH suggests the plumes there are very different, if they exist at all. This enhanced-color view shows a 350- by 750-kilometer swath Rathbun’s findings, titled “A closer look at Galileo thermal data from across the surface of Jupiter’s moon Europa. Research by Robert Nelson of the Planetary Science Institute shows that Europa’s possible plume sources near Pwyll, Europa,” were presented at a press surface could be 95 percent porous, allowing visiting spacecraft to conference at the Division for Planetary Sciences of the American sink into the moon’s surface. Astronomical Society 50th annual meeting in Knoxville, Tenn. Credit: NASA/JPL-Caltech/SETI Institute

Rathbun’s work follows up on earlier observations that suggested ABOVE RIGHT: Jupiter Cyclones a plume originating from an area north of Pwyll on Europa, and When Juno flies over Jupiter’s poles only half the planet is in sunlight – the other half is in the dark of night. For this reason, to see the reanalysis of Galileo magnetometer and plasma data also suggests clouds in the entire south polar region, images from Juno’s first and a plume source about 1,000 kilometers northeast of the first site. fourth close passes are combined in this illustration. The combined image clearly shows a set of five circumpolar cyclones arranged in Hansen’s efforts to engage citizen scientists in furthering the study of a pentagon around the polar cyclone approximately in the middle Jupiter saw continued success. of this picture. Farther from the poles cyclonic and anticyclonic storms swirl around in a turbulent region unlike the familiar stripes Hansen oversees the JunoCam outreach camera program that engages of Jupiter’s belts and zones. Credit: NASA/SwRI/MSSS/Gerald Eichstädt /John Rogers the public in planning images of Jupiter resulted in many amazing images of Jupiter. Amateur astronomers supply images from their on the order of the wavelength of light of the observations (a fraction backyard telescopes for planning. Citizen scientists and artists of a micron). This corresponds to material that would be less dense download raw images and then contribute their own processed than freshly fallen snow, raising questions about the risk of a Europa versions to the JunoCam online gallery (https://www.missionjuno. lander sinking into the surface of the Jupiter satellite. swri.edu/junocam/processing). Observations were made using a goniometric photopolarimeter Research by PSI Senior Scientist Robert Nelson shows that of novel design located at Mt. San Antonio College in Walnut, spacecraft landing on Jupiter’s moon Europa could see the craft California. The powders used were aluminum oxide (Al2O3), which sink due to high surface porosity. is an excellent regolith analog for high albedo airless bodies in the Nelson was the lead author of a laboratory study of the photopola- Solar System, including water ice bodies such as Europa. rimetric properties of bright particles that explain unusual negative “Of course, before the landing of the Luna 2 robotic spacecraft in polarization behavior at low phase angles observed for decades in 1959, there was concern that the Moon might be covered in low association with atmosphereless bodies including asteroids 44 Nysa, density dust into which any future astronauts might sink,” Nelson 64 Angelina and the Galilean satellites Io, Europa and Ganymede. said. “However, we must keep in mind that remote visible-wave- These observations are explained by extremely fine-grained particles length observations of objects like Europa are only probing the with void space greater than about 95 percent. Grain sizes would be outermost microns of the surface.”

7 Mysterious Rings, Water Sources Studied On Saturn’s Satellites

Mysterious straight bright stripes have been discovered on Saturn’s Above: Cassini VIMS infrared view of Saturn moon Dione, PSI Associate Research Scientist Alex Patthoff found. Blue is infrared light where water ice reflects relatively brightly. Red is longer wavelength thermal emission showing heat from deep inside The origins of these linear “virgae” (virgae meaning a stripe or streak the planet. Green is infrared wavelengths where aurora emit light. of color) are most likely caused by the draping of surface materials Above left: Phoebe in visible light. Phoebe is very dark, like charcoal, whereas the rings are very bright in visible light like slightly dirty snow. like material from Saturn’s rings, passing comets, or co-orbital The Saturn image was a NASA Astronomy Picture of the Day (APOD): moons Helene and Polydeuces. https://apod.nasa.gov/apod/ap100927.html Credit: NASA, JPL, VIMS Team, ISS Team, U. Arizona, D. Machacek, “The evidence preserved in the linear virgae has implications for U. Leicester the orbital evolution and impact processes within the Saturnian system,” Patthoff said. “The interaction of Dione’s surface and exogenic material has implications for its habitability and provides differences in the formation of a planet, moon, or comet, and evidence for the delivery of ingredients that may contribute to the changes the evaporation of water after formation. The deuterium to habitability of ocean worlds in general. hydrogen ratio (D/H) is a fingerprint of the formation conditions, including temperature and evolution over time. “Their orientation, parallel to the equator, and linearity are unlike anything else we’ve seen in the Solar System,” Patthoff said. “If they The discovery of an unusual deuterium to hydrogen isotopic ratio for are caused by an exogenic source, that could be another means to Saturn’s moon Phoebe means it was formed in and comes from a far bring new material to Dione. That material could have implications part of the cold outer Solar System far beyond Saturn, Clark said. for the biological potential of Dione’s subsurface ocean.” The measurements were made from the NASA Cassini spacecraft By developing a new method for measuring isotopic ratios of water using the Visual and Infrared Mapping Spectrometer (VIMS) over and carbon dioxide remotely, scientists led by PSI Senior Scientist the course of the mission. An improved calibration of the instrument, Roger N. Clark have found that the water in Saturn’s rings and completed early in 2018, enabled the precision needed for these satellites is unexpectedly like water on the Earth, except on Saturn’s measurements of reflected light from the rings and satellites. The moon Phoebe, where the water is more unusual than on any other new method of measuring isotopic ratios on solids like water ice object so far studied in the Solar System. This means we need to and carbon dioxide ice using reflectance spectroscopy remotely will change models of the formation of the Solar System because the new enable measurements of isotopic ratios for other objects throughout results are in conflict with existing models. the Solar System, putting further constraints on models of Solar System formation. Isotopes are different forms of elements but with differing numbers of neutrons. Adding a neutron adds mass to the element, and that The Saturn system D/H values close to the Earth’s values imply a can change processes of how a planet, comet, or moon is formed. similar water source for the inner and outer Solar System, and new Water is composed of two hydrogen (H) atoms and one oxygen models need to be developed where the change from inner to outer atom, H2O. Adding a neutron to one hydrogen atom, then called Solar System is less. deuterium (D), increases the mass of a water molecule (HDO) by about 5 percent, and that small change results in isotopic

8 NEW TECHNIQUE INVESTIGATES ICE ON MARS

A new investigative technique shows the latitudinal distribution of ice-rich landforms on Mars. This large-scale study enables future, more detailed investigations to study several young deposits of ice and sediment in the north polar basin. MARS ICE DEPOSITS Localization of the studied regions in the northern plains of Mars “The young ice deposits are extremely important for several reasons. First, they represent a different epoch in Mars’ climate history when one mile beneath the layers of ice and dust that comprise the south ice was stable at the mid-latitudes. We can probe them for more polar cap of Mars. information and gather details about Mars’ climate,” said Isaac B. Smith, PSI Research Scientist and co-author of three new papers The potential existence of such subglacial reservoirs of liquid water on the topic. “Second, if humans are to explore Mars, they will on Mars – which could have offered a habitable haven for native life want to go to mid-latitude locations where the Sun is up all year. on Mars – was first discussed by Clifford in a paper entitled “Polar Identifying where the ice is supports that. Finally, astrobiologists Basal Melting on Mars,” published in the Journal of Geophysical are very interested in locations where ice and rock interact because Research on August 10, 1987. it may offer clues about habitability.” On Earth, microorganisms have been found in the subglacial lakes of The northern plains of Mars are comprised of several basins filled by Antarctica that have existed in isolation from the external Antarctic sediments. The region has been proposed to have hosted an ancient environment for 35 million years or more and, since many of the 400 ocean and currently contains ice in the ground even at latitudes subglacial lakes that have been identified so far appear to be hydrau- where the ice is not stable. lically connected, it is reasonable to conclude that microbial life may exist nearly everywhere beneath the Antarctic ice, Clifford said. “We used this type of investigation to speed up the process of seeking ground ice. The team broke up very long sections into 20 kilometer The discovery of life in a subglacial lake on Mars would have by 20 kilometer squares,” Smith said. “This sped up the process of enormous significance for our understanding of the prevalence of interpreting huge areas by orders of magnitude. The benefit is that life in our Solar System. Ice-covered oceans are believed to exist we can now trace the latitudinal placement of various features on Europa, Ganymede, Enceladus, Titan, Triton, and several other in a spatial context, useful for making conclusions about ground bodies in the Solar System. ice on Mars.” PSI Senior Scientist R. Aileen Yingst was in the driver’s seat Feb. 15, Smith supported the research by providing information on what is directing the science activities for NASA’s Opportunity Rover as it found beneath the Martian surface using his analysis of data from spent its 5,000th day exploring the Martian surface. Yingst served as NASA’s Mars SHAllow RADar sounder (SHARAD) instrument on Science Operations Working Group chairperson, running the group the Mars Reconnaissance Orbiter spacecraft. that decided what the rover did that sol, or Martian day.

The announcement of the presence of liquid water beneath the “I headed up the science planning for what Opportunity did during surface of Martian poles validates research published by PSI Senior sol 5,000,” said Yingst, who is an Associate Principal Investigator for Scientist Stephen Clifford back in 1987. Data collected by the the rover. “The rover got a nice selfie shot to mark the day. We also Mars Advanced Radar for Subsurface and Ionospheric Sounding imaged a channel in which the rover has been driving. It’s another (MARSIS) orbital radar sounder on the European Space Agency’s day at the office, but the office is millions of miles away. Science on Mars Express spacecraft points to a lake of liquid water buried about Mars is always special, amazing, incredible and different.” 9 DAWN RUNS OUT OF FUEL, GOES SILENT AFTER 11-YEAR ODYSSEY OF DATA COLLECTION

NASA’s Dawn spacecraft has gone silent, ending an 11-year odyssey mantle, and one of the possible mechanisms to reduce friction could that explored the two largest objects in the main asteroid belt, giant be an ancient water ocean beneath the crust.” asteroid Vesta and dwarf planet Ceres. The Dawn mission has orbited Ceres for more than three years, Dawn has run out of fuel, ending a mission on which dozens of gathering very detailed observations and allowing the construction Planetary Science Institute researchers have worked. While the Dawn of precise geophysical models. These models can then be adapted spacecraft’s mission officially came to an end, results keep flowing for comparison to other icy bodies, Tricarico said. One such from analysis of data collected during the mission to Ceres and example is the parallel between the well-known equatorial ridge Vesta. The spacecraft can no longer keep its antennae trained on of Iapetus, the moon of Saturn, and the remnants of the paleo- Earth to speak or listen to mission control, and can no longer turn equatorial ridge of Ceres. its solar panels to the sun for recharging. Finite Element Method models used to analyze images from Dawn Current PSI scientists who worked on the Dawn mission include show Ceres has experienced cryovolcanism throughout its geologic Bruce Barraclough, Dan Berman, David Crown, William Feldman, history, with an average surface extrusion rate of about 10,000 cubic Amara Graps, Margaret Landis, Lucille Le Corre, Jian-Yang Li, Scott meters per year, orders of magnitude lower than that of basaltic Mest, Jeff Morgenthaler, Beatrice Mueller, David O’Brien, Eric Palmer, volcanism on the terrestrial planets. Thomas Platz, Thomas Prettyman, Robert Reedy, Norbert Schörghofer, Icy volcanoes have erupted throughout the history of Ceres, but Hanna Sizemore, Mark Sykes, Bryan Travis, Pasquale Tricarico, such continuous activity has not had the same extensive impact on Naoyuki Yamashita and Aileen Yingst. PSI alumni who worked on the dwarf planet’s surface as standard volcanism on Earth, says a Dawn include Vishnu Reddy, Brent Garry and Lynnae Quick. Nature Astronomy paper “Cryovolcanic rates on Ceres revealed by Senior Scientist Pasquale Tricarico found that Ceres experienced a topography.” Michael M. Sori of the University of Arizona Lunar and polar reorientation of approximately 36 degrees. Using data from Planetary Laboratory is lead author, and PSI Senior Scientist Hanna the Dawn mission, Tricarico determined the magnitude of the G. Sizemore is second author. reorientation with three independent and corroborating lines of Cryovolcanoes erupt liquid or gaseous volatiles such as water, evidence. Global Gravity Inversion, from a paper Tricarico published ammonia or methane instead of spewing molten rock as seen on in 2013, helped determine the density variations of Ceres, especially Earth. Salty water is likely the major component of cryolavas on in the crust. This is what was used to find the equatorial density Ceres. Ceres offers the best opportunity to test the significance of anomaly. Statistical analysis of topography was used for ridge cryovolcanism on outer Solar System bodies, compared to regular analysis and the paleo-pole. And for matching the crustal fractures, volcanism on terrestrial planets like Earth. a well-proven method by Isamu Matsuyama and Francis Nimmo was used. “There was a great deal of interest in searching for cryovolcanoes on Ceres as soon as Dawn arrived there, because thermal models “The most surprising aspect of this paper is to me the observation had predicted they might exist. Ahuna Mons was a great candidate that the pole of Ceres must have followed an indirect path to its right away. I carried out a global search that identified 31 other large current pole. A multi-step reorientation could mean that the domes, based on analysis of Dawn’s Framing Camera images and equatorial density anomaly was still evolving during the topography data,” Sizemore said. “Making the case that they were reorientation, and this could be because the crust and mantle volcanic was difficult because they were more ancient than Ahuna were weakly rotationally coupled, allowing the crust to start and the surfaces were heavily cratered. In this study, we were able to reorienting while the mantle would lag behind,” Tricarico said. compare the shapes of the mountains to numerical models of how “If crust and mantle are allowed to shift with respect to one another, they should relax over time if they were made out of icy lava. That that could point to a layer of reduced friction between crust and 10 “Ceres is a little world that ought to be ‘dead,’ but these new results suggest it might not be. Seeing so much potential evidence for cryovolcanism on Ceres also lends more weight to discussions of cryovolcanic processes on larger icy moons in the outer Solar System, where it’s likely more vigorous.” —Hanna G. Sizemore, PSI Senior Scientist

strengthened the case that they were volcanic features, and let us OPPOSITE PAGE TOP: CERES make comparisons to volcanism on other planets.” This photo of Ceres and one of its key landmarks, Ahuna Mons, was one of the last views Dawn transmitted before it completed its mission. “Given how small Ceres is, and how quickly it cooled off after its This view, which faces south, was captured at an altitude of 2220 miles formation, it would be exciting to identify only one or two possible (3570 kilometers) as the spacecraft was ascending in its elliptical orbit. Ahuna Mons has been interpreted as a cryovolcanic edifice. Numerous cryovolcanoes on the surface. To identify a large population of older, more rounded mountains, like those seen in the lower half of features that may be cryovolcanoes would suggest a long history this image, give Ceres a “lumpy” appearance. These mountains may of volcanism extending up to nearly the present day, which is be more ancient volcanoes, revealing a long history of volcanism on Ceres. tremendously exciting,” said Sizemore. “Ceres is a little world that Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA ought to be ‘dead,’ but these new results suggest it might not be. Seeing so much potential evidence for cryovolcanism on Ceres also GHOSTED BACKGROUND IMAGE: CERES lends more weight to discussions of cryovolcanic processes on larger Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA icy moons in the outer Solar System, where it’s likely more vigorous.”

Feng and Griffin Named 2019 Pierazzo Award Winners

Ying (Katherina) Feng and Sammy Griffin were named winners of the 2019 Pierazzo International Student Travel Award. The Pierazzo Award was established by PSI in memory of Senior Scientist Betty Pierazzo to support and encourage graduate students to build international collaborations and relationships in planetary science. Feng, of the University of California, Santa Cruz will receive the award for a U.S.-based graduate student traveling to a planetary meeting outside the U.S. Her research title is “Probing the Phase Dependence of Atmospheric Inference for Hot Jupiters” and she PIERAZZO AWARD WINNERS will be attending the Exoclimes V conference at Oxford, the United Left: Ying (Katherina) Feng Right: Sammy Griffin Kingdom, Aug. 12-15, 2019. Griffin, of the University of Glasgow, will receive the award for a non-U.S.-based graduate traveling to a planetary meeting within the U.S. Her research title is “New Insights into the Magmatic and Shock History of the Naklite Meteorites from Electron Backscatter Diffraction” and she will be attending the 50th Lunar and Planetary Science Conference in Houston, Texas, March 18-22, 2019. A PSI representative will present each awardee with a certificate and check for $2,000 at their respective conferences. 11 PSI Continues To Expand As it has been for more than 45 years, PSI’s strength and advantage continue to be in its people. Our culture of openness and high level of mutual support distinguishes us as an organization. In 2018 PSI continued to grow, adding 21 new research and administrative staff members.

New PSI staff members for 2018:

Zachary M. Bain Stephen Clifford Jianqing Feng Pamela L. Gay Amber Grav Student Research Assistant Senior Scientist Postdoctoral Research Scientist Senior Scientist & Senior Education Technical Document Writer and Communication Specialist

Triana Hernandez-Henz David Hornisher Alan Howard Georgiana Kramer Margaret E. Landis Student Research Assistant Technical Support Specialist Senior Scientist Senior Scientist Postdoctoral Research Scientist

Chien-Hsiu Lee Cynthia K. Little Stephen P. Scheidt Lorenzo Tavazzani Kevin D. Webster Associate Research Scientist Senior Research Associate Associate Research Scientist Graduate Student Research Assistant Associate Research Scientist

NOT PICTURED:

Sophia Borowsky Student Research Assistant

Mackenzie White Graduate Student Research Assistant

Bailey Williamson Jason W. Witry Stephen E. Wood Chun N. Wu Student Research Assistant Research Assistant Senior Scientist Student Junior Software Programmer

12 PSI’s Education and Public Outreach Has Global Reach

PSI supports many science education and “Citizen Science” projects that have a national and international reach. Currently, our scientists, education specialists, staff, and docents are based in 23 states, the District of Columbia, and several international locations. In 2018 we announced that all funding from the “Friends of PSI” EPO AT SPACE CENTER HOUSTON program (see www.psi/support/friends for more info) will support Georgiana Kramer accompanied members of the Boys and Girls Club the wide variety of Education and Public Outreach (EPO) initiatives of Greater Houston on a trip to Space Center Houston, the official visitor center of NASA Johnson Space Center, where she discussed the that our scientists and educators undertake in their own communities Moon for their “Living on the Moon” art project. through events, workshops, and science fairs. We are always seeking new ways to demonstrate our commitment to reaching and inspiring Don Davis, Maya Bakerman, Connor McNally, Joe Spitale, Bea the next generation of scientists. Mueller and Mike Drum. The diversity of programs led by our scientists ranges from participation in events with an epic global reach such as the Thousands of Family SciFest 2018 Attendees Enjoy STEM-Based Activities International Observe the Moon Night to chatting about planetary PSI offered kids of all ages a chance to learn about meteorites and science and ongoing space missions with the local shoppers at a use an infrared (IR) camera at the Seventh Annual Family SciFest event farmer’s market in Colorado. held at Children’s Museum Tucson. The event attracted 2,264 people Some of the past year’s EPO highlighs included: and featured hands-on activities presented by 39 exhibitors. PSI Active at International Observe the Moon Night Events Sanlyn Buxner and Maya Bakerman were kept busy throughout the event by a constant stream of kids and parents visiting PSI’s Andrea Jones led NASA’s Lunar Reconnaissance Orbiter (LRO) display table. outreach team in the most popular International Observe the Moon Night (InOMN) to date with more than 1,000 registered events and PSI Holds Teacher Lunar Workshop an estimated 160,000 participants in 75 countries around the globe. Three PSI educators participated in the Arizona Science Teacher Georgiana Kramer gave an International Observe the Moon Association’s “Terra Luna” event held at the Franklin Phonetic Skype presentation with Q&A with a group at The Space Station School in Prescott, Ariz. Museum in Novato, California. She also accompanied members of Maya Bakerman, Sanlyn Buxner and Larry Lebofsky held a the Boys and Girls Club of Greater Houston on a trip to Space Center Moon-focused workshop for teachers that included meteorite kits, Houston, the official visitor center of NASA Johnson Space Center, moon mapping, Earth-Moon comparisons, Moon phase activities, where she discussed the Moon for their “Living on the Moon” cratering activities and studying historic images from NASA’s Lunar art project. Reconnaissance Orbiter. Locally, PSI collaborated with the University of Arizona’s And More Flandrau Science Center and Planetarium to provide activities for Georgiana Kramer donned a superhero costume to offer girls InOMN. People flocked to take part in the hands-on educational an opportunity to see the power of science and be inspired by what activities and to make use of an array of telescopes on the UA Mall is possible when they embrace their personal power. She made to observe the Moon. The Tucson Amateur Astronomy Association appearances as The Lunatic Phenomenon, as part of the Female provided the telescopes. Superheroes of Science group that made planetary science-based Tucson Festival of Books Features PSI Researchers, Educators presentations to schools and girls’ organizations. PSI’s display at the Tucson Festival of Books attracted hundreds Not only do PSI scientists engage with students, parents, of visitors during the two-day event held on the University of teachers, and the general public at museums, schools, and festivals, Arizona Mall. PSI’s exhibit, held in the event’s Science City area, but they also encourage their peers at other organizations to conduct included hands-on activities featuring samples of three different EPO activities. For example, Jennifer Grier presented “Understanding types of meteorites – stony, iron, and stony-iron, as well as many the Needs of Space Scientists in Education, Public Engagement, different types of impact rocks which were created when meteorites and Communications: Implications for Practice” at the Lunar and impacted with Earth. Planetary Science Conference held in March. Larry Lebofsky scheduled volunteers for the event, and PSI scientists serve as judges in science fairs such as the Southern participants included Thea Cañizo, Stephen Ferris, Vivian Morrison, Arizona Research, Science, and Engineering Foundation (SARSEF) and PSI contributes prizes to the winners. 13 PSI Fundraising and Development

PSI is a nonprofit research organization and it relies on NASA contracts for the majority of its funding. Because the NASA budget is vulnerable to budget cuts (and, unfortunately, government shutdowns as was witnessed this year), it is necessary for PSI to seek private sector donations to augment the funding that it receives from NASA. To sustain the Institute’s nationwide Education and Public Outreach (EPO) efforts we reach out to businesses and individuals (both local and national) to support our activities through their tax-deductible contributions. Throughout the year, PSI conducts a few different fundraising events and campaigns that include: ANNUAL DINNER Annual Dinner Top: Featured speaker Pamela Melroy, PSI Board of Trustees Chair Tim The PSI Annual Fundraising Dinner is the organization’s Hunter and Benjamin Smith chat prior to the Annual Fundraising Dinner. flagship event. The 2018 Dinner featured former Astronaut and Bottom: Guests check out the wide variety of raffle items offered at the dinner. Space Shuttle Commander, Pamela Melroy (Colonel, USAF, Ret.) as the keynote speaker. Pam’s riveting presentation provided highlights press release announcements, and alerts about scientists’ podcasts. of her spaceflight experience including a step-by-step narration of This year we made a significant change in the “Friends of PSI” a spacewalk to repair damage to the International Space Station’s program, allocating all “Friends” revenue to support the Institute’s Solar Array. During her remarkable career Pam has logged more EPO activities. than 38 days in space. She is the recipient of numerous awards and PSI scientists and educators log many hours in their respective special honors including the NASA Distinguished Service Medal, the communities, volunteering their time at events such as Science Fairs, NASA Outstanding Leadership Medal, and the Air Force Meritorious Astronomy Nights, and other STEM-related activities. These important Service Medal, among others. outreach activities can include the use of one of the Institute’s custom The event’s table sponsors included PSI Board members, PSI Rock/Meteor Kits for “hands on” demonstrations. The funding from staff members, and local businesses that generously support the the “Friends” program enables PSI to ship these kits and to develop Institute’s work. appropriate collateral materials to enhance the presentations. One of the evening’s fun highlights was the raffle prize drawing Betty Pierazzo Fund that included dozens of rare and unique items such as a scale model of Vesta (modeled in chocolate!), NASA collectibles, books, spa Created to honor the late Elizabeth Pierazzo, a PSI Senior Scientist, treatments, jewelry, artwork, and a vacation weekend. this fund assists early-career scientists. Two students are selected each year (one U.S.-based, one international-based) who receive a Challenge Match Campaign check of $2,000 to defray the cost of their travel to attend a scientific PSI’s year-end “Challenge Match Campaign” is now in its fourth conference. year and continues to provide much-needed unrestricted revenue for Belton Fund the Institute. To launch the 2018 Challenge Campaign a group of Created by Michael and Anna Don Belton, this fund supports generous PSI supporters cumulatively pledged $12,000 to form the a biennial Symposium on Comets. The inaugural event is planned campaign’s revenue goal. To receive the pledged sum PSI was required to raise matching funds. Thanks to the generosity of our donors, the for 2020. campaign was a great success. The total raised exceeded the goal Grants and Business Sponsorships amount by 35 percent. Additional funding efforts include submitting grant applications Friends of PSI Program and making presentations to Tucson-area businesses identified as possible donors and/or sponsors for a specific research area and/or The “Friends of PSI” program is the Institute’s core group of supporters. This group is comprised of individuals and businesses for EPO efforts. who further PSI’s global work through an annual, tax-deductible Other membership donation. “Friends” receive the PSI Quarterly PSI continues to partner with Amazon through the AmazonSmile Newsletter, a discount on tickets to the Annual Dinner, breaking news program and a PSI Gift Shop is available on the PSI website. 14 THaNK You To our 2018 BeNefaCTorS With deep appreciation the Planetary Science Institute acknowledges the following individual and organizational benefactors who made contributions between Jan. 1, 2018 and Dec. 31, 2018. $15,000 and up $100-$249 Mr. Ivo Van der ryt dr. Mark V. Sykes and Ms. Marilyn Guengerich anonymous dr. david Vaniman and Ms. donna Gary Mr. and Mrs. alfred and Maria anzaldua Mr. Tom M. Vovers $5,000-$14,999 Mr. alex Berman dr. Kevin Webster dr. david P. Brown Mr. and Mrs. robert and Judith Breault dr. and Mrs. Stuart J. and Suzy Weidenschilling dr. Jay Melosh Mr. Joshua Cahill dr. Paul Weissman Mr. Kenneth Wilcox $2,000-$4,999 dr. Thea L. Cañizo Ms. Alexa Carlo-Hickman Ms. Patricia Wong Conoco Phillips Mrs. Bessie T. Chan $1-$99 dr. and Mrs. William and Gayle Hartmann Mr. and Mrs. Paul and etta Chan Mr. xakarus alldredge dr. and Mrs. Tim and Carol Hunter Mr. Stewart C. Chan dr. and Mrs. Brent and Joanne archinal Col. Pamela Melroy, retired Mr. and Ms. robert and elisabeth Chrien dr. and Mrs. Victor and Pauline Baker Vector Ms. florence don Ms. Greer Barkley Mr. and Mrs. Bruce and Lynne dusenberry $1,000-$1,999 Ms. Julie Bates Mr. and Mrs. Larry and Judith east anonymous Mr. and dr. William and Kathleen Bethel Mr. Stephen fleming Mr. and Mrs. Maurizio and Tina Balistreri Mr. Gary Bingham Ms. Janet e. fong Mr. Bruce Barnett and Ms. Tammi Palmer Mr. and Mrs. Bill and ann Buckmaster Lt. Col. robert Gent and Judge Terrie Gent drs. donald r. davis and diana e. Wheeler Mr. John Cerney dr. amanda Hendrix and Mr. david richardson echo Construction Ms. Kathleen Chan dr. Vicki Hansen Mr. and dr. John and dorothy oehler Mr. Christopher Chyba Mr. and Mrs. david and Shirley Hartmann Ms. ann Cleaves $500-$999 Mr. douglas Huie Ms. Linda K. Conroy dr. david Johnson anonymous Mr. Avery Davis and Mrs. Debbie Golden-Davis Mr. dave Kretsinger anonymous Ms. Norma J. don dr. C. darrell Lane dr. Michael Belton and Ms. anna don Mr. Paul emmert Mr. Taft Lee The Mahoney Group Mrs. Veronica flournoy Mr. Stephen J. Lew drs. Beatrice Mueller and Tod Lauer Mrs. Bernice Gin Ms. rosina Y. Lim National Bank of arizona Mr. donald Gin dr. Cynthia Little Ms. erin C. Neal Mr. Terrence Greenwood Mr. and Mrs. richard and Christine Logan dr. robert M. Nelson and Ms. Marguerite renner dr. david fales and Ms. Sara Hammond dr. franklin L. Louie r & a CPas Mr. Sidney M. Hirsh Mr. arthur Mabbett dr. and Mrs. robert and Maria reedy Ms. Chris Holmberg Ms. Melissa a. McGrath Lt. Col. and Mrs. William and Marilyn Sykes Mr. Stephen d. Hopkins drs. robert and Gloria McMillan dr. faith Vilas and Mr. Larry Smith Mr. William e. Houghton dr. and Mrs. andrew and anna Nelson Wolf & Sultan, P.C. dr. Tim Jull Ms. Sherryl Nelson Mr. Charles Katzenmeyer $250-$499 Mr. and Mrs. John and Kathleen o’Brien dr. d. Terence Langendoen and Ms. Nancy Kelly Mr. and Mrs. Joe and diana alexander Ms. Beatrice N. Parker Mrs. Louise W. Lee dr. and Mrs. William and Barbara Bickel Mr. Neil C. Pearson dr. and Mrs. Kurt and elisabeth Marti CodaC Behavioral Health Services dr. Thomas H. Prettyman Ms. audrey Mondet dr. uwe fink drs. Vishnu reddy and Lucille Le Corre Ms. Joy a. Neverman Ms. Kimberly foote dr. Nalin Samarasinha Mr. Kenneth Scoville dr. and Mrs. James and Molly Head Ms. desiree Schaub dr. Sarah Sutton Mr. ed Jackson Mrs. Susanna Schippers Mr. eric d. Tarallo dr. and Mrs. Lee and donna rogers Mr. Claud Smith dr. Henry Throop Mr. and Mrs. otto and Linda rueger Mr. and Mrs. dennis and Lynette Smith Tucson Chinese Golf Club Mr. Benjamin Smith and Ms. Liisa Phillips Mr. randy Sooter Mr. anthony Villari dr. alan Stern dr. anna Spitz Mr. Peeranut Visetsuth dr. Sugata Tan dr. andrew Wheeler dr. Michelle Thomsen Ms. Tiny M. Wong dr. and Mrs. Bryan J. and Gayle L. Travis

15 PSI Financial Report

Bruce Barnett Chief Financial Officer

PSI continues to experience annual growth with revenues totaling $13.1 million for the fiscal year ended Sept. 30, 2018. During the fiscal year, PSI was actively involved in 118 prime awards issued by federal agencies and 137 subawards/contracts issued by other institutions. Ninety-seven percent of all funding originated from NASA.

REVENUES Active projects by prime awarding agency Grants and Contracts $12,926,497 NASA 246 Contributions 188,765 NSF 4 Other 16,619 USGS 1 Total Revenues $13,131,881 Non-Federal 4 Total Projects 255

Salaries and related fringe benefits represent 76 percent of PSI’s total expenses of $13 million. Operating expenses include $1.1 million paid on subawards to other institutions whose scientists are included on PSI prime awards. Program services expenses were 88 percent of total expenses.

EXPENSES EXPENSES by Function

Salaries and Benefits $ 9,861,427 Program Services $ 11,453,127 Operating 2,877,543 Management & General 1,465,579 Depreciation 160,783 Fundraising 34,507 Interest 53,460 Total Expenses $ 12,953,213 Total Expenses $ 12,953,213

PSI’s financial records are audited annually by independent auditors. A condensed Statement of Financial Position from PSI’s audit report as of Sept. 30, 2018 is reflected below.

Current Assets $ 2,234,394 Current Liabilities $ 1,727,990 Property & Equipment, Net 1,123,937 Long-term Liabilities 951,124 Total Assets $ 3,358,331 Net Assets with Donor Restrictions 105,850 Net Assets without Donor Restrictions 573,367 Total Liabilities & Net Assets $ 3,358,331

16 New PSI Research Grants

Oleg Abramov. Constraining lunar bombardment history by modeling Jamie Molaro. Microstructural evolution of Solar System ices through impact age distributions. NASA Solar System Workings program. sintering. NASA Solar System Workings program. Sanlyn Buxner. The Lucy student pipeline accelerator and competency Jamie Molaro. Enceladus surface sample acquisition for in situ measure- enabler (L’SPACE) program. NASA Discovery Mission: Lucy Mission ments. Jet Propulsion Laboratory subcontract. Phase B. Arizona State University subaward. Gareth Morgan. Mini-RF cornerstone extended mission. NASA Lunar Roger Clark. Earth surface material dust source investigation (EMIT). Reconnaissance Orbiter “Cornerstone” extended mission, Johns Hopkins NASA Earth Space Mineral Dust Source Investigation (EMIT). Jet University Applied Physics Laboratory subcontract. Propulsion Laboratory subcontract. Gareth Morgan. Local subsurface ice mapping through the integration Steve Clifford. An integrated atmospheric and subsurface investigation of SHARAD derived data products with other datasets. Jet Propulsion of the evolution of the early Martian hydrosphere: Implications for the Laboratory subcontract. occurrence and duration of potentially habitable liquid water environments Gareth Morgan. NASA Mars Reconnaissance Orbiter extended mission on a cold early Mars. NASA Habitable Worlds program. #4 (EM4). NASA Mars Reconnaissance Orbiter program, Jet Propulsion Deborah Domingue. The impact of solar wind ions on the surface and Laboratory subcontract. exosphere of Mercury. NASA Solar System Workings program. The Catherine Neish. The mini-RF instrument. NASA Lunar Reconnaissance Trustees of Columbia University subaward. Orbiter program, The Johns Hopkins University Applied Physics Darby Dyar. Venus in situ composition investigations (VICI). NASA New Laboratory subcontract. Frontiers mission. Eldar Noe Dobrea. Powered paragliding on Venus. Empirical Systems Paul Hardersen. Citizen science and students: Engaging populations Aerospace subcontract. to accomplish fundamental astronomical research. NASA Topical Eldar Noe Dobrea. Laboratory assessment of supercontinuum laser (SLC) Workshops, Symposia, and Conferences program. spectrometer. Ames Research Innovation Award. Amanda Hendrix. Constraining the surface composition of Europa Eric Palmer. Stereophotoclinometry (SPC) short course. PSI consulting with spatially resolved mid-UV spectra. NASA Hubble Space Telescope services. mission, Space Telescope Science Institute subcontract. Eric Palmer. DART phases C/D. NASA Double Asteroid Redirection Amanda Hendrix. The UV reflectance of Patroclus: Exploring the surface Test program, The Johns Hopkins University Applied Physics Laboratory composition and origins of Jupiter Trojans. NASA Hubble Space Telescope subcontract. mission, Space Telescope Science Institute subcontract. Asmin Pathare. Lunar and Martian crater production in the last billion Amanda Hendrix. Unmasking the dark side of Iapetus. NASA Hubble years. NASA Solar System Workings program, University of California Los Space Telescope mission, Space Telescope Science Institute subcontract. Angeles subaward. Amanda Hendrix. Characterizing enigmatic Phaethon in the UV. NASA Alex Patthoff. Characterizing the mysterious linear virgae across the Hubble Space Telescope mission, Space Telescope Science Institute mid-sized satellites in the Saturnian system. Cassini Data Analysis subcontract. program, Smithsonian Institution subaward. Alan Howard. Assessing a cold-icy vs. warm-wet climate for early Mars Neil Pearson. Laboratory support services for building, operation and with valley network morphometry and landscape evolution models. NASA training of a vacuum spectroscopy facility. PSI consulting services. Mars Data Analysis program, University of Colorado Boulder subaward. Thomas Prettyman. 2001 Odyssey gamma ray spectrometer extended Alan Howard. Interface development and documentation for a planetary mission. NASA Odyssey program, University of Arizona subcontract. landform evolution simulation platform. NASA Planetary Data Archiving, Nathaniel Putzig. Subsurface water ice mapping (SWIM) in the northern Restoration, and Tools program, SETI Institute subaward. hemisphere of Mars. NASA Mapping of Water Deposits to Support Mars Catherine Johnson. Fluxgate magnetometer for InSight, Mars lander, Exploration Program Studies, Jet Propulsion Laboratory subcontract. Discovery mission. NASA InSight mission, University of California Los Julie Rathbun. Rapid response and novel research in Earth science. NASA Angeles subcontract. Rapid Response and Novel Research in Earth Science program. Catherine Johnson. Europa Clipper ICEMAG instrument preliminary Jim Rice. MER geomorphic and sedimentological investigations. NASA design review. NASA Europa mission, Jet Propulsion Laboratory subcontract. Mars Exploration Rover mission, Jet Propulsion Laboratory subcontract. Jeff Kargel. Astrobiology at the water-rock interface and beyond. NASA Nalin Samarasinha. Non-gravitational forces and torque in Comet 67P/ Astrobiology program, Jet Propulsion Laboratory transfer. Churyumov-Gerasimenko and determining their relationship to cometary Jeff Kargel. Large landslides and landslide/glacier-dammed Himalayan activity. NASA Rosetta Data Analysis program. and Karakoram rivers and the potential for transboundary disruptions. Juan Sanchez. Physical characterization of small near-Earth asteroids. NASA Interdisciplinary Research in Earth Science program. NASA Solar System Observations program, University of Arizona subaward. Jian-Yang Li. Determining the mineralogical evolution to asteroid (145) Matthew Siegler. Thermal conductivity measurement of regolith down Adeona through degree of aqueous alteration to support Dawn extended to T = 15 K. NASA Solar System Workings program, Jet Propulsion mission. NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) Laboratory subcontract. program, Universities Space Research Association – Cycle Six General Observer Grant. Elizabeth Sklute. Collaborative research: Formation, stability, and detection of amorphous ferric sulfate salts on Mars. National Science Jian-Yang Li. A Python package for small-body astronomy. NASA Plan- Foundation, Planetary Astronomy program. etary Data Archiving, Restoration, and Tools program, Lowell Observatory subaward. Elizabeth Sklute. Ultraviolet through mid-infrared optical constants of minerals and glasses relevant to planetary spectroscopic analyses. NASA Jian-Yang Li. Close encounter with comet 46P/Wirtanen: X-ray tomography Primary Data Archiving, Restoration and Tools program, The Research of the coma. NASA Hubble Space Telescope mission, Space Telescope Foundation for the State University of New York subaward. Science Institute subcontract. Jordan Steckloff. Investigating clouds on Titan. NASA Cassini Data Scott Mest. Updating the geologic maps of the Apollo 15-16-17 landing Analysis program, Southwest Research Institute subaward. sites. NASA Planetary Data Archiving, Restoration, and Tools program. 17 Jordan Steckloff. Early evolution and survivability of amorphous Cathy Weitz. Geologic mapping of dark mantle deposits in Sinus water ice within small icy bodies. NASA Emerging Worlds program. Aestuum and Mare Vaporum. NASA Lunar Data Analysis program. Sugata Tan. Habitability of hydrocarbon worlds: Titan and beyond. Cathy Weitz. Constraining the geology and near surface properties of NASA Astrobiology Institute CAN-8, Jet Propulsion Laboratory the InSight landing site. NASA InSight program, Smithsonian Institution subcontract. subcontract.

Ryan Watkins. Blue Origin Strategy Advisory Board. PSI consulting Chuck Wood. Laboratory simulation of CO2 and H2O frosts on Mars. services. NASA Solar System Workings program.

PSI publications

Adriani, A., A. Mura, G. Orton, C. Hansen, F. Altieri, M.L. Moriconi, Belton, M.J., X.-D. Zou, J.-Y. Li, E. Asphaug (2018). On the origin of J. Rogers, G. Eichstädt, T. Momary, A. Ingersoll, G. Filacchione, G. Sindoni, internal layers in comet nuclei. Icarus 314, 364-375. F. Tabataba-Vakili, B.M. Dinelli, F. Fabiano, S.J. Bolton, J.E.P. Connerney, Belton, M.J.S., O.R. Hainaut, K.J. Meech, B.E.A. Mueller, J.T. Kleyna, H.A. S.K. Atreya, J.L. Lunine, F. Tosi, A. Migliorini, D. Grassi, G. Piccioni, Weaver, M.W. Buie, M. Drahus, P. Guzik, R. Wainscoat, W. Waniak, B. R. Noschese, A. Cicchetti, C. Plainaki, A. Olivieri, M.E. O’Neill, D. Turrini, Handzlik, S. Kurowki, S. Xu, S.S. Scott, M. Micheli, H. Ebeling, J.V. Keane S. Stefani, R. Sordini, M. Amoroso (2018). Clusters of cyclones encircling (2018). The excited spin state of 1I/2017 U1 ‘Oumuamua. Astrophy. J. Lett. Jupiter’s poles. Nature 555, 216-219. 865, Id. L21. Anderson, B.J., C.L. Johnson, H. Korth, L.C. Philpott (2018). Birkeland Benecchi, S.D., C.M. Lisse, E.L. Ryan, R.P. Binzel, M.E. Schwamb, L.A. currents at Mercury: Review and comparison with Earth. In Electric Currents Young, A.J. Verbiscer (2018). K2 precision lightcurve: Twelve days in the in Geospace and Beyond (A. Keiling, O. Marghitu, M. Wheatland, Eds.). Pluto-Charon system. Icarus 314, 265-273. Geophys. Mono. 235, 279-302. Berman, D.C., M.R. Balme, J.R. Michalski, S.C. Clark, E.C.S. Joseph Applin, D.M., M.R.M. Izawa, E.A. Cloutis, J. Gillis-Davis, A.R. Hendrix, (2018). High-resolution investigations of transverse aeolian ridges on F. Vilas, N. R. Izenberg (2018). Ultraviolet spectral reflectance of carbo- Mars. Icarus 312, 247-266. naceous phases and applications to remote sensing of planetary surfaces. Bernardini, F., N. Putzig, E. Petersen, A. Abbud-Madrid, V. Giacinti Icarus 307, 40-82. (2018). Implications for resource utilization on Mars: Recent discoveries Augera, A.T., O. Groussin, L. Jorda, M.R. El-Maarry, S. Bouley, A. Séjourné, and hypotheses. J. Brit. Interplanet. Soc. 71, 186-189. R. Gaskell, C. Capanna, B. Davidsson, S. Marchi, S. Höfner, P.L. Lamy, Birch, S.P.D., A.G. Hayes, P. Corlies, E.R. Stofan, J.D. Hofgartner, R.M.C. H. Sierks, C. Barbieri, R. Rodrigoj, D. Koschny, H. Rickman, H.U. Keller, Lopes, R.D. Lorenz, J.I. Lunine, S.M. MacKenzie, M.J. Malaska, C.A. J. Agarwal, M.F. A’Hearn, M.A. Barucci, J.L. Bertaux, I. Bertini, G. Cremonese, V. Da Deppo, S. Debei, M. De Cecco, S. Fornasier, M. Fulle, P.J. Gutiérrez, Wood, Cassini Radar Team (2018). Morphological evidence that Titan’s C. Güttler, S. Hviid, W.-H. Ip, J. Knollenberg, J.R. Kramm, E. Kührt, M. southern hemisphere basins are paleoseas. Icarus 310, 140-148. Küppers, L.M. Lara, M. Lazzarini, J.J. Lopez Moreno, F. Marzari, M. Bishop, M.A. (2018). Dark dunes of Mars: An orbit-to-ground multidis- Massironi, H. Michalik, G. Naletto, N. Oklay, A. Pommerol, L. Sabau, ciplinary perspective of aeolian science. In Dynamic Mars: Recent and N. Thomas, C. Tubiana, J.B. Vincent, K.P. Wenzel (2018). Meter-scale thermal Current Landscape Evolution of the Red Planet (R.J. Soare, S.J. Conway, contraction crack polygons on the nucleus of comet 67P/Churyumov- S.M. Clifford, Eds.). Elsevier, 317-360. Gerasimenko. Icarus 301, 173-188. Boivin, A.L., D. Hickson, C. Tsai, A. Cunje, R.R. Ghent, M.G. Daly (2018). Azari, A.R., M.W. Liemohn, X. Jia, M.F. Thomsen, D.G. Mitchell, N. Broadband measurements of the complex permittivity of carbonaceous Sergis, A.M. Rymer, G.B. Hospodarsky, C. Paranicas, J. Vandegriff (2018). asteroid regolith analog materials. J. Geophys. Res. Planet. 123, 3088-3104. Interchange injections at Saturn: Statistical survey of energetic H+ sudden Bray, V., C. Atwood-Stone, C.D. Neish, N. Artemieva, A. McEwen, J.N. flux intensifications. J. Geophys. Res. 123, 4692-4711. McElwaine (2018). Lobate impact melt flows within the extended ejecta Baines, K.H., L.A. Sromovsky, P.M. Fry, T.W. Momary, R.H. Brown, B.J. blanket of Pierazzo crater. Icarus 301, 26-36. Buratti, R.N. Clark, P.D. Nicholson, C. Sotin (2018). The eye of Saturn’s Bristow, T.F., E.B. Rampe, C.N. Achilles, D.F. Blake, S.J. Chipera, P. Craig, north polar vortex: Unexpected cloud structures observed at high spatial J.A. Crisp, D.J. Des Marais, R.T. Downs, R. Gellert, J.P. Grotzinger, S. Gupta, resolution by Cassini/VIMS. Geophys. Res. Lett. 45, 5867-5875. R.M. Hazen, B. Horgan, J.V. Hogancamp, N. Mangold, P.R. Mahaffy, A.C. Baker, M.M., M.G.A. Lapotre, M.E. Minitti, C.E. Newman, R. Sullivan, McAdam, D.W. Ming, J.M. Morookian, R.V. Morris, S.M. Morrison, A.H. C.M. Weitz, D.M. Rubin, A.R. Vasavada, N.T. Bridges, K.W. Lewis (2018). Treiman, D.T. Vaniman, A.R. Vasavada, A.S. Yen (2018). Clay mineral di- The Bagnold Dunes in southern summer: Active sediment transport on versity and abundance in sedimentary rocks of Gale crater, Mars. Mars. Mars observed by the Curiosity rover. Geophys. Res. Lett. 45, 8853-8863. Sci. 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23 PSI 2018 ANNUAL RETREAT

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