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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS2014

Origins of the Lunar and Planetary Laboratory, University of Arizona

The roots of the Lunar and Planetary Laboratory (LPL) extend deep into the rich fabric of G. P. Kuiper's view of the Earth as a planet and planetary systems as expected companions to most stars, as well as the post-war emergent technology of infrared detectors suitable for astronomy. These concepts and events began with Kuiper's theoretical work at Yerkes Observatory on the origin of the Solar System, his discovery of two planetary satellites and observational work with his near-infrared spectrometer on the then-new McDonald 82-inch telescope in the mid- to late-1940s. A grant for the production of a photographic atlas of the Moon in the mid-1950s enabled him to assemble the best existing images of the Moon and acquire new photographs. This brought E. A. Whitaker and D. W. G. Arthur to Yerkes. Others who joined in the lunar work were geologist Carl S. Huzzen and grad student E. P. Moore, as well as undergrad summer students A. B. Binder and D. P. Cruikshank (both in 1958). The Atlas was published in 1959, and work began on an orthographic lunar atlas. Kuiper's view of planetary science as an interdisciplinary enterprise encompassing astronomy, geology, and atmospheric physics inspired his vision of a research institution and an academic curriculum tuned to the combination of all the scientific disciplines embraced in a comprehensive study of the planets. Arrangements were made with the University of Arizona (UA) to establish LPL in affiliation with the widely recognized Inst. of Atmospheric Physics. Kuiper moved to the UA in late 1960, taking the lunar experts, graduate student T. C. Owen (planetary atmospheres), and associate B. M. Middlehurst along. G. van Biesbroeck also joined the migration to Tucson; Binder and Cruikshank followed along as new grad students. Astronomy grad student W. K. Hartmann came into the academic program at UA and the research group at LPL in 1961. Senior faculty affiliating with LPL in the earliest years were T. Gehrels, A. B. Meinel, H. L. Johnson, and F. J. Low, each with their own grad students and associates. Work began on IR spectroscopy and a rectified lunar atlas. Kuiper and Johnson started the search for future observatory sites in N. America and Hawaii.

Planets↗
NASA NTRS2015

A Path to Planetary Protection Requirements for Human Exploration: A Literature Review and Systems Engineering Approach

As systems, technologies, and plans for the human exploration of Mars and other destinations beyond low Earth orbit begin to coalesce, it is imperative that frequent and early consideration is given to how planetary protection practices and policy will be upheld. While the development of formal planetary protection requirements for future human space systems and operations may still be a few years from fruition, guidance to appropriately influence mission and system design will be needed soon to avoid costly design and operational changes. The path to constructing such requirements is a journey that espouses key systems engineering practices of understanding shared goals, objectives and concerns, identifying key stakeholders, and iterating a draft requirement set to gain community consensus. This paper traces through each of these practices, beginning with a literature review of nearly three decades of publications addressing planetary protection concerns with respect to human exploration. Key goals, objectives and concerns, particularly with respect to notional requirements, required studies and research, and technology development needs have been compiled and categorized to provide a current 'state of knowledge'. This information, combined with the identification of key stakeholders in upholding planetary protection concerns for human missions, has yielded a draft requirement set that might feed future iteration among space system designers, exploration scientists, and the mission operations community. Combining the information collected with a proposed forward path will hopefully yield a mutually agreeable set of timely, verifiable, and practical requirements for human space exploration that will uphold international commitment to planetary protection.

Johnson, James E.↗
NASA NTRS2018

Magnetour: Surfing Planetary Systems on Electromagnetic and Multi-Body Gravity Fields

In this NIAC Phase One study, we propose a new mission concept, named Magnetour, to facilitate the exploration of outer planet systems and address both power and propulsion challenges. Our approach would enable a single spacecraft to orbit and travel between multiple moons of an outer planet, with no propellant required. Our approach would enable a single spacecraft to orbit and travel between multiple moons of an outer planet, with no propellant nor onboard power source required. To achieve this free-lunch _Grand Tour', we exploit the unexplored combination of magnetic and multi-body gravitational fields of planetary systems, with a unique focus on using a bare tether for power and propulsion. The main objective of the study is to develop this conceptually novel mission architecture, explore its design space, and investigate its feasibility and applicability to enhance the exploration of planetary systems within a 10-year timeframe. Propellantless propulsion technology offers enormous potential to transform the way NASA conducts outer planet missions. We hope to demonstrate that our free-lunch tour concept can replace heavy, costly, traditional chemical-based missions and can open up a new variety of trajectories around outer planets. Leveraging the powerful magnetic and multi-body gravity fields of planetary systems to travel freely among planetary moons would allow for long-term missions and provide unique scientific capabilities and flagship-class science for a fraction of the mass and cost of traditional concepts. New mission design techniques are needed to fully exploit the potential of this new concept.This final report contains the results and findings of the Phase One study, and is organized as follows. First, an overview of the Magnetour mission concept is presented. Then, the research methodology adopted for this Phase One study is described, followed by a brief outline of the main findings and their correspondence with the original Phase One task plan. Next, an overview of the environment of outer planets is provided, including magnetosphere, radiation belt and planetary moons. Then performance of electrodynamic tethers is assessed, as well as other electromagnetic systems. A method to exploit multi-body dynamics is given next. These analyses allow us to carry out a Jovian mission design to gain insight in the benefits of Magnetour. In addition, a spacecraft configuration is presented that fully incorporates the tether in the design. Finally technology roadmap considerations are discussed.

Gravity Fields↗
NASA NTRS2014

Northern Late Winter Planetary Waves: MRO/MARCI Observations and Mars Climate Model Simulations

As does Earth, Mars presents pronounced global atmospheric circulation patterns. Solar differential heating drives mean meridional overturning (Hadley) circulations which are deep and intense, are hemispherically asymmetric, and where a cross-equatorial single cell dominates. Within middle and high latitudes, thermally indirect eddy-driven (Ferrel) circulation cells have been indicated. Differently, however, large-amplitude orography on planetary and continental scales on Mars can force very non-Earth-like hemispheric circulation patterns. Recent observations from the Mars Reconnaissance Orbiter, "Mars Color Imager" (MARCI) instrument are utilized that emphasize water ice clouds in ultra-violet (UV) wavelengths, and these measurements have been binned into "daily global maps" (DGMs) of water-ice cloud optical depth. The presence of large-scale, extratropical quasi-stationary atmospheric wave disturbances in middle and late winter of the northern hemisphere have been found to be present in such DGMs. In combination with such observations, a full-physics Mars global climate model (NASA ARC marsgcm 2.1) is applied to place the observations into context. During late northern winter, it is found that strong, forced Rossby modes (i.e., planetary waves) exist, and with direct correlation to columnintegrated cloud opacity undulating spatial patterns. At this season, zonal wavenumber s = 2 dominates (in contrast to wavenumber s = 1), consistent with MGS/TES analyses at this particular season (Banfield et al., 2003). Large-scale, planetary waves dictate the "coherence" of the northern polar vortex. Fundamentally, such forced planetary waves influence the polar vortex's impermeability (wave-induced) to tracer transport (e.g., dust and water-ice aerosol) and temporal mean water vapor spatial variations. The large-scale dynamical features of such planetary waves will be highlighted and discussed.

Northern polar vortex↗
NASA NTRS2020

Feeding Ten Billion People Is Possible Within Four Terrestrial Planetary Boundaries

Global agriculture puts heavy pressure on planetary boundaries, posing the challenge to achieve future food security without compromising Earth system resilience. On the basis of process-detailed, spatially explicit representation of four interlinked planetary boundaries (biosphere integrity, land-system change, freshwater use, nitrogen flows) and agricultural systems in an internally consistent model framework, we here show that almost half of current global food production depends on planetary boundary transgressions. Hotspot regions, mainly in Asia, even face simultaneous transgression of multiple underlying local boundaries. If these boundaries were strictly respected, the present food system could provide a balanced diet (2,355 kcal per capita per day) for 3.4 billion people only. However, as we also demonstrate, transformation towards more sustainable production and consumption patterns could support 10.2 billion people within the planetary boundaries analysed. Key prerequisites are spatially redistributed cropland, improved water–nutrient management, food waste reduction and dietary changes. Adoption of the Sustainable Development Goals by all nations in 2015 is the first ever commitment to a world development path that safeguards the stability of the Earth system as a prerequisite for meeting universal human standards1. The longstanding challenge of achieving food security through sustainable agriculture is particularly acute in this context as world agriculture is a leading cause for the current transgressions of multiple planetary boundaries (PBs) globally and regionally2–5. The PB framework is a comprehensive scientific attempt to synoptically define our planet’s biogeophysical limits to anthropogenic interference. It suggests bounds to nine interacting processes that together delineate a Holocene-like Earth system state. The Holocene is chosen as the reference state as it is the only period known to provide a safe operating space for a world population of several billion people, and according to a precautionary principle, the PBs are set in sufficient distance from processes that may critically undermine Earth system resilience and global sustainability. A challenging question, thus, is whether human development goals such as food security can be met while maintaining multiple PBs along with their subglobal manifestations. Further PB transgressions could jeopardize the chances of providing sufficient food for a world population projected to be wealthier and reach >9 billion by 2050. This conundrum portrays a tradeoff between Earth’s biophysical carrying capacity and humankind’s rising food demand, calling in response for radical rethinking of food production and consumption patterns6–9. Yield gap closures, avoidance of excessive input use, shifts towards less resource-demanding diets, food waste reductions and efficient international trade are crucial options for sustainably increasing the food supply10–15. For example, enhancing water-use efficiency on irrigated and rain-fed farms can triple or quadruple crop yields in low-performing systems, suggesting possible global gains of >20% (ref. 16). Even higher gains appear feasible through globally optimized configurations of the land-use pattern17, and cutting food losses by half could generate food for another billion people18. Thus, collective large-scale implementation of such options could sustain food for a further growing world population19. Yet achieving this within a safe operating space as defined by PBs requires not only a halt to but actually a reversal of existing PB transgressions. Previous studies suggest that such a reconciliation might be possible, but these were based on aggregate representations of PBs (not accounting for the spatial patterns of limits, transgressions and interactions) or considered only one boundary in isolation17,20–23. Here, we systematically quantify to what extent current food production depends on local to global transgressions of the PBs for biosphere integrity, land-system change, freshwater use and nitrogen (N) flows, along with the potential of a range of solutions to avoid these transgressions and still increase food supply (Table 1). To this end, we configured an internally consistent process-based model of the terrestrial biosphere including agriculture (LPJmL) with multiple spatially distributed PBs and their interactions. LPJmL is among the longest-established and best-evaluated biosphere models, showing robust performance regarding simulation of, for example, carbon, water and crop yield dynamics (Supplementary Figs. 1 and 2 and Supplementary Table 1; see ref. 24 for a comprehensive benchmarking and Supplementary Methods for more detail on model evaluations). In principle following established definitions4, we refine the computation of some PBs with respect to their regional patterns and interactions (Methods), providing globally gridded precautionary limits to human interference with the Earth system at a level of great detail. In particular, we account for the evidence that many PBs need to be represented spatially explicitly4 to cover their

Gerten, Dieter↗
NASA NTRS2020

Nonbinary Systems: Looking Towards the Future of Gender Equity in Planetary Science

Gender equity remains a major issue facing the field of planetary science, and there is broad interest in addressing gender disparities within space science and related disciplines. Many studies of these topics have been performed by professional planetary scientists who are relatively unfamiliar with research in fields such as gender studies and sociology. As a result, they adopt a normative view of gender as a binary choice of ‘male’ or ‘female,’ leaving planetary scientists whose genders do not fit within that model out of such research entirely. Reductive frameworks of gender and an overemphasis on quantification as an indicator of gendered phenomena are harmful to people of marginalized genders, especially those who live at the intersections of multiple axes of marginalization such as race, disability, and socioeconomic status. In order for the planetary science community to best serve its marginalized members as we move into the next decade, a new paradigm must be established. This paper aims to address the future of gender equity in planetary science by recommending better survey practices and institutional policies based on a more profound approach to gender.

Beck E Strauss↗
NASA NTRSDate not supplied

Multi-Anvil Experimentation Applied to Planetary Differentiation

Planets undergo differentiation that includes segregation of metal from silicate at high temperatures and pressures ranging from deep planetary core pressures (>300 GPa for Earth)to very shallow conditions of asteroids (<100 MPa).The multi-anvil solid media apparatus accesses the middle part of this range from 3 to 30 GPa –pressure relevant to the interior of Mercury, Venus, Earth, Earth’s Moon, and Mars. Early planets are thought to have experienced high temperatures from a combination of heat sources including radioactive decay, gravitational and accretional heating, and impact processes. These heating events led to melting of mantles and cores, thus requiring an understanding of solid-liquid equilibria in metal-silicate systems. In 2006 we established a multi-anvil facility at NASA-JSC combining an 880 ton press and a Kawai/Walker type module from Rockland Research. Our high PT work has been greatly facilitated by use of the COMPRES multi-anvil assemblies (1). Our recent work has included studies of element partitioning between liquid metal and liquid silicate(e.g., 2), as well as between minerals and melts(e.g., 3), both of which have led to better constraints on the timing and conditions of planetary differentiation(e.g. 4). Several examples involving sustained efforts will be summarized below and for the presentation. The distribution of siderophile (iron-loving) elements between core and mantle is controlled by metal-silicate equilibrium across a wide range of pressures. Therefore, experimentation across this pressure range helps to calibrate elemental partitioning models that can be applied to planets, and used to predict mantle chemistry and composition during planetary differentiation. Our studies have focused on a wide range of siderophile elements (refractory Ni, Co, W, Mo; volatile P, Ga, Cu, Sn, Sb; highly siderophile Au, Pd) that have constrained partitioning, valence, and isotopic fractionation, and applied to Earth, Moon, and Mars. When molten mantles (magma oceans) cool enough to initiate crystallization, the solids precipitate at depth and in large planets this involves high pressure phases like garnet, majorite, akimotoite, and ringwoodite. As these solids precipitate they can segregate from liquid by density contrasts, thus causing elemental fractionation which can be used to decipher timing of differentiation. Mineral/melt and metal/silicate equilibria in our lab have helped to better understand high pressure fractionation of isotopic parent/daughter pairs Hf/W, Mn/Cr, Pd/Ag, Pt/Os, Re/Os, and U/Pb, and their application to Earth, Moon and Mars. There remains great potential for multi-anvil experimentation to shed light on many pressure–dependent aspects of planetary evolution such as core formation, high pressure phase equilibria, redox equilibria, and volatile evolution and storage. References1. Leinenweber, K., et al.(2012) American Mineralogist,97, 353–368. 2.Righter, K., et al.(2020) Geochem. Persp. Lett.15, 1-6.3. Righter, K., et al.(2020) Met. Planet. Sci 55, 2741-2757.4. Righter, K., et al.(2020)Earth and Planetary Science Letters,552, 116590.

pressure↗
NASA NTRS2020

Bayesian Framework For Bioburden Density Calculations To Perform Planetary Protection Probabilistic Risk Assessment

The planetary protection discipline aims to minimize the microbial contamination on spacecraft to prevent the inadvertent contamination of other planetary bodies, known as forward planetary protection (PP). Planetary protection probabilistic risk assessment (PRA) relies on two core methodologies-the contamination probability event tree analysis and statistical parameter estimation. Planetary protection engineers combine several techniques to estimate the bioburden present on spacecraft components. A direct assay to enumerate CFU (colony forming units) is the preferred methodology, but given a similar processing environment the bioburden present on certain components is inferred using: (1) a NASA defined bioburden estimate based upon the biological cleanliness of the manufacturing/assembly environment or (2) sampled data from a similar spacecraft component. The paper presents an empirical Bayesian framework to systematically treat bioburden estimation and its uncertainties on different levels starting with measurement procedures to combining different components to subsystems and whole spacecraft. It is shown that the Bayesian approach can effectively handle estimations and their uncertainties at different levels and produce a reliable estimate for bioburden to be used to evaluate the probability of contamination.

Seuylemezian, Arman↗
NASA NTRSDate not supplied

The NASA Facility for Astromaterials Research at the Johnson Space Center – A National Laboratory for Planetary Research

The Astromaterials Research and Exploration Science (ARES) Division at the NASA Johnson Space Center houses a unique combination of laboratories, instruments, infrastructure, technical ex-pertise, and other assets for conducting broad-based world-class planetary research. These facilities have been accessed for decades by hundreds of external scientists, including faculty, post-docs, students, and interns, most at no cost and on a collaborative basis. With funding through NASA’s Planetary Science Enabling Facilities (PSEF) program, we have estab-lished the NASA Facility for Astromaterials Research (NFAR) to expand access to and enhance these labora-tories for a diverse and inclusive external user base, thus maximizing the science return from research funded by R&A programs in NASA’s Planetary Sci-ence Division (PSD). NFAR enables cutting edge planetary sample analyses, making new scientific dis-coveries possible, in addition to training the next-generation of planetary scientists. NFAR laboratories are co-located with JSC Curation that houses all NASA-controlled astromaterials collections, thus ena-bling direct access to both research and curation exper-tise, to facilitate specialized sample handling and anal-ysis of allocated samples (from JSC and other sample collections) to PIs, particularly those affiliated with institutions that historically have limited or no access to in-house analytical or experimental facilities.

J Filiberto↗
NASA NTRSDate not supplied

Results of the 2022 Mental Health Survey of the Planetary Science Community

The mental health struggles within academia and research are well recognized in the science community and have been further illustrated by the numerous cultural memes and comics (e.g., PhD Comics). With the recent COVID-19 pandemic, mental health has become a topic of concern more so than ever before, as depression and anxiety have become an invisible consequence of social isolation and distancing. In addition, recent social events in the United States have reignited attention towards important social injustices surrounding people of color, women, and LGBTQ+ in academia. If diversity, equity, inclusion, and accessibility are to become major components of improving planetary science, it is also important to understand the mental health status of the community, as it could expose deeply embedded policies, rules, and culture that may hinder any work in sustaining and advancing people belonging to marginalized groups. Studies have been conducted to further understand the mental health of those in academia. These studies have shown that before the pandemic, there was a mental health crisis among graduate students, which became a larger problem with increasing anxiety and depression due to the pandemic. Soon after, the planetary science community recognized this concern in the recent 2023 Planetary Science Decadal White Paper, which proposed that NASA should invest in understanding the scope and impact of mental health problems within the planetary science community and how to address the issue. In this study, we conducted a mental health survey to examine the mental health of the planetary science community. We examined the overall anxiety, depression, and stress severity of the community, rather than diagnosing the community’s condition or determining the proportion of the population having a clinical anxiety, depressive, stress, or trauma-related diagnosis. To emphasize, the results are not intended to make clinical diagnoses, nor are they being used to do so for the purpose of this study.

D Trang↗
NASA NTRSDate not supplied

Analytical Modeling of Planetary Excavation for in Situ Resource Utilization

The space-faring capabilities of humans are dependent on the ability to interact with plan-etary surfaces safely and efficiently and utilize local re-sources. Since planetary regolith will be the primary feedstock for in situ resource utilization (ISRU) and infrastructure development activities [1,2], the site-specific geomechanical properties must be understood to optimize excavation operations [3]. Excavating planetary regolith is challenging due to its unique geomechanical properties, 1/6th G reduced gravity extreme conditions, and limited energy resources. Therefore, it is critical to develop technologies that reduce excavation force requirements and minimize tool path inefficiencies to save time and energy during planetary re-source acquisition and infrastructure development [3]. There have been several experimental investigations of methods to optimize planetary excavations [4,5], but none developed predictive capabilities. This abstract presents a simple analytical method that will be used to model laboratory and mission excavation data. Future work will build on the simple analytical method here to include high-fidelity numerical simulations of planetary excavation mechanics.

Regolith↗
NASA NTRS2024

The NASA Facility for Astromaterials Research at the Johnson Space Center – A National Laboratory for Planetary Research

The Astromaterials Research and Exploration Science (ARES) Division at the NASA Johnson Space Center houses a unique combination of laboratories, instruments, infrastructure, technical expertise, and other assets for conducting broad-based world-class planetary research. These facilities have been accessed for decades by hundreds of external scientists, including faculty, post-docs, students, and interns, most at no-cost and on a collaborative basis. With funding through NASA’s Planetary Science Enabling Facilities (PSEF) program, we have established the NASA Facility for Astromaterials Research (NFAR) to expand access to and enhance these laboratories for a diverse and inclusive external user base, focusing on training of the next generation of scientists and, thus, maximizing the science return from research funded by R&A programs in NASA’s Planetary Science Division (PSD). NFAR enables new planetary sample analyses, making new scientific discoveries possible, including training the next generation of planetary scientists. NFAR laboratories are co-located with JSC Curation that houses the NASA-controlled astromaterials collections, thus enabling direct access to both research and curation expertise, to facilitate specialized sample handling and analysis of allocated samples to sample PIs, particularly those affiliated with institutions that historically have limited access to or lack in-house analytical or experimental facilities.

J. I. Simon↗
NASA NTRS2024

A Survey of the Severity of Mental Health Symptoms in the Planetary Science Community

There is a growing recognition of a mental health crisis within the academic and research communities. Members of the planetary science community have called for healthier work environments to improve mental well-being. As a preliminary step towards improving workplace culture, we sought to determine if the broader mental health crisis extends to planetary science and assess the severity of anxiety, depressive, and stress symptoms. Our 2022 mental health survey of the planetary science community suggests that the severity of anxiety and depressive symptoms in the community is greater than in the general US population. Further, the anxiety and depressive symptoms are more severe for graduate students and postdoctoral researchers than any other career stage. Comparing groups within planetary science, we found that anxiety, depressive, and/or stress symptoms appear greater among marginalized groups, such as women, people of color, and members of the LGBTQ+ community. A mental health problem is impacting the planetary science community. Improving well-being will promote enhanced research quality and productivity.

David Trang↗
NASA NTRSDate not supplied

The Need for Earth-Based Experiments to Inform Microbial Evolution on Planetary Surfaces

Introduction: Historically, the focus of planetary protection at NASA has been on unmanned, robotic missions. Such missions have paved the way for understanding how to implement planetary protection in a feasible and cost-sensitive way. However, with the introduction of crewed missions to Mars in the not-sodistant future, there is a need to better define and understand how to implement planetary protection under new circumstances, as well as understand the risk of contaminating Mars. One unavoidable fact is that microbes will go where humans go. Therefore, it is critical to understand how these microbes may (and will) impact our ability to conduct meaningful, reliable astrobiological science. Microorganisms have spent millions of years evolving to survive in extreme environments here on Earth. Already there are indications that microbes aboard the International Space Station evolve and adapt to life in low earth orbit. The microbes that are eventually taken to Mars with humans will also adapt, potentially causing harmful effects to crew and/or the planetary or astrobiological science conducted. Therefore, it is of critical interest that we evaluate and characterize the potential risks of microbial evolution on Mars. It is expected that microbes carried by humans will begin to evolve to new environments even before landing on Mars, during the several month cruise phase. Once landed, microbes will encounter different stressors within the crew habitats on Mars. During extravehicular activities, venting, or other release events, microbes will find their way out onto the Martian surface. The induced environments around crewed systems will create potentially-favorable conditions for microbes to continue evolving on Mars. Eventually, microbes may find their way beyond the close confines of the crewed area and continue evolving so as to fill new or distant niches on the Martian surface. It is challenging to replicate Martian environments here on Earth, making it nearly impossible to predict the evolutionary changes that microbes would undergo on Mars. But this work is critical. Serial passaging experiments performed by Richard Lenski on E. coli show the dramatic changes microbes can undergo even within a laboratory setting. Furthermore, experiments performed by Michael Baym also demonstrate the power of single mutations in microbial development of antibiotic resistance [3]. Long duration experiments should be performed on a suite of microbes exposed to environments likely to be experienced on the Martian surface. While simulating space environments can be challenging, facilities exist that can achieve individual and combinatorial environmental conditions to simulate space and planetary conditions. Such chambers should be employed for microbial studies. Currently, at the Marshall Space Flight Center, we have used various stressors like drying, vacuum, proton radiation, and ultraviolet light both separately and in combination, to evaluate the survival of cleanroom microbes. Shockingly, several non-spore forming isolates have demonstrated the ability to survive many extreme conditions (manuscript in preparation). These short duration exposures must be augmented with larger and more gradual studies to replicate what microbes might experience in the transition from cruise, to surface habitats, to induced surface environments, and finally true Martian environments. While no Earth-based experiment can perfectly replicate the Martian environment, nor could we test every possible microbe in simulation experimental regimes, efforts should be made to examine the evolutionary potential of the “usual suspects” seen on the ISS or in other crewed environments to begin to fill this important knowledge gap.

Chelsi D. Cassilly↗
NASA NTRS2015

Planetary Radar

This chapter describes the principles of planetary radar, and the primary scientific discoveries that have been made using this technique. The chapter starts by describing the different types of radar systems and how they are used to acquire images and accurate topography of planetary surfaces and probe their subsurface structure. It then explains how these products can be used to understand the properties of the target being investigated. Several examples of discoveries made with planetary radar are then summarized, covering solar system objects from Mercury to Saturn. Finally, opportunities for future discoveries in planetary radar are outlined and discussed.

Radar↗
NASA NTRS2022

A History of the NASA Planetary Astronomy Program: 1958-2022

For decades, the public has been enraptured by popular high-resolution images and data taken of our multicolored planets by space-based telescopes. However, at the time NASA was established in October 1958, there was limited astronomical interest in planetary science with ground-based telescopes. Instead, stellar astronomy dominated most of the observing time at facilities, as astrophysics was considered the forefront of astronomical research. Once NASA determined that it wanted launch planetary missions to explore the solar system in detail, it became obvious that there were not enough high-quality solar system observations to lay the foundation for these missions. Therefore, the NASA Planetary Astronomy program (PAST) was established to fund ground-based research on solar system objects. This research covers the history of this important but little-known NASA program, which not only provided necessary support for planetary missions but also was responsible for rejuvenating astronomer interest in solar system research.

NASA PAST Program↗
DOE OSTI2024

Achievement of the Planetary Defense Investigations of the Double Asteroid Redirection Test (DART) Mission

NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos near-Earth asteroid binary system, demonstrating an autonomously navigated kinetic impact into an asteroid with limited prior knowledge for planetary defense. Months of subsequent Earth-based observations showed that the binary orbital period was changed by –33.24 minutes, with two independent analysis methods each reporting a 1 σ uncertainty of 1.4 s. Dynamical models determined that the momentum enhancement factor, β , resulting from DART's kinetic impact test is between 2.4 and 4.9, depending on the mass of Dimorphos, which remains the largest source of uncertainty. Over five dozen telescopes across the globe and in space, along with the Light Italian CubeSat for Imaging of Asteroids, have contributed to DART's investigations. These combined investigations have addressed topics related to the ejecta, dynamics, impact event, and properties of both asteroids in the binary system. A year following DART's successful impact into Dimorphos, the mission has achieved its planetary defense requirements, although work to further understand DART's kinetic impact test and the Didymos system will continue. In particular, ESA's Hera mission is planned to perform extensive measurements in 2027 during its rendezvous with the Didymos–Dimorphos system, building on DART to advance our knowledge and continue the ongoing international collaboration for planetary defense.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2006

The Validation of Vapor Phase Hydrogen Peroxide Microbial Reduction for Planetary Protection and a Proposed Vacuum Process Specification

The Jet Propulsion Laboratory, in conjunction with the NASA Planetary Protection Officer, has selected the vapor phase hydrogen peroxide sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal is to include this technique, with an appropriate specification, in NPR 8020.12C as a low temperature complementary technique to the dry heat sterilization process.To meet microbial reduction requirements for all Mars in-situ life detection and sample return missions, various planetary spacecraft subsystems will have to be exposed to a qualified sterilization process. This process could be the elevated temperature dry heat sterilization process (~115 C for 40 hours) which was used to sterilize the Viking lander spacecraft. However, with utilization of such elements as highly sophisticated electronics and sensors in modern spacecraft, this process presents significant materials challenges and is thus an undesirable bioburden reduction method to design engineers. The objective of this work is to introduce vapor hydrogen peroxide (VHP) as an alternative to dry heat microbial reduction to meet planetary protection requirements.The VHP process is widely used by the medical industry to sterilize surgical instruments and biomedical devices, but high doses of VHP may degrade the performance of flight hardware, or compromise material properties. Our goal for this study was to determine the minimum VHP process conditions to achieve microbial reduction levels acceptable for planetary protection.

planetary protection↗