NASA Planetary Research Articles

Near-earth asteroid (66391) Moshup (1999 KW4) observing campaign: Results from a global planetary defense characterization exercise

Hazards due to near-Earth objects (NEOs) continue to pose a threat to life on Earth. While our capability for discovering NEOs has steadily progressed over the last three decades, physical characterization of a representative population has lagged behind. To test the operational readiness of the global planetary defense capabilities, we conducted a community-led global planetary defense exercise, with support from the NASA's Planetary Defense Coordination Office (PDCO) and the International Asteroid Warning Network (IAWN), to test the operational readiness of global planetary defense capabilities. This campaign focused on the characterization (direct imaging, radar, spectroscopy) of the binary near-Earth asteroid (NEA) (66391) Moshup (formerly known as 1999 KW4) and its moon Squannit. We chose a binary system because roughly one in six large NEAs are binaries. An additional goal was to apply lessons learned from this campaign towards ground-based characterization campaign for binary NEA (65803) Didymos, the target of the PDCO's Double Asteroid Redirection Test (DART) and the European Space Agency's Hera missions. Spectral observations of Moshup from the NASA Infrared Telescope Facility (IRTF) show similarities to Q-type asteroids. Based on its spectral band parameters, the best meteorite analogs for Moshup are L chondrites. We did not detect a hydration feature at 3 μm, which suggests that the entire surface is anhydrous. We imaged the binary using the SPHERE instrument on the Very Large Telescope (VLT) and obtained resolved spectral measurements of Moshup similar to those obtained with the NASA IRTF. Squannit appears to have slightly redder spectral slope than Moshup. Radar observations Arecibo Observatory at 2380 MHz indicate a polarization ratio of ~0.4, which is higher than the average values for the S complex asteroids, which includes Q types. The visible extent of the components from the radar observations, taken as proxies for their radii, suggest Moshup and Squannit have diameters of 1500 ± 120 m and 480 ± 60 m, respectively. We constrain the system mass to 2.2 ± 0.5 × 1012 kg with a maximum range for bulk density between ~0.8 g/cm3 for a very low-mass system with spherical shapes up to 2.7 g/cm3 for very high-mass system where Moshup has a more ridged-ball shape. We note that the radar-derived parameters presented in the paper are for the purposes of this exercise and do not supersede those in Ostro et al. (2006). We assessed the impact risk of a hypothetical impactor based on Moshup's physical properties using the Probabilistic Asteroid Impact Risk (PAIR) model. We assessed three impact risk scenarios at different epochs as the state of knowledge of Moshup improved. For kilometer-scale impactors like Moshup, the risk is driven predominantly by the potential for global climatic effects (95–97% of cases across the epochs) with a few percent driven by local damage and a few tenths of a percent driven by tsunami.

Performance of Multiple Metagenomics Pipelines in Understanding Microbial Diversity of a Low-Biomass Spacecraft Assembly Facility.

NASA planetary protection (PP) requires an assessment of the biological contamination of the potential microbial burden on spacecraft destined to explore planetary bodies that may harbor signs of life, like Mars and Europa. To help meet these goals, the performance of multiple metagenomic pipelines were compared and assessed for their ability to detect microbial diversity of a low-biomass clean room environment used to build spacecraft destined to these planetary bodies. Four vendors were chosen to implement their own metagenomic analysis pipeline on the shotgun sequences retrieved from environmental surfaces in the relevant environments at NASA’s Jet Propulsion Laboratory. None of the vendors showed the same microbial profile patterns when analyzing same raw dataset since each vendor used different pipelines, which begs the question of the validity of a single pipeline to be recommended for future NASA missions. All four vendors detected species of interest, including spore-forming and extremotolerant bacteria, that have the potential to hitch-hike on spacecraft and contaminate the planetary bodies explored. Some vendors demonstrated through functional analysis of the metagenomes that the molecular mechanisms for spore-formation and extremotolerance were represented in the data. However, relative abundances of these microorganisms varied drastically between vendor analyses, questioning the ability of these pipelines to quantify the number of PP-relevant microorganisms on a spacecraft surface. Metagenomics offers tantalizing access to the genetic and functional potential of a microbial community that may offer NASA a viable method for microbial burden assays for planetary protection purposes. However, future development of technologies such as streamlining the processing of shotgun metagenome sequence data, long read sequencing, and all-inclusive larger curated and annotated microbial genome databases will be required to validate and translate relative abundances into an actionable assessment of PP-related microbes of interest. Additionally, the future development of machine learning and artificial intelligence techniques could help enhance the quality of these metagenomic analyses by providing more accurate identification of the genetic and functional potential of a microbial community.

Mars Image Content Classification: Three Years of NASA Deployment and Recent Advances

The NASA Planetary Data System hosts millions of images acquired from the planet Mars. To help users quickly find images of interest, we have developed and deployed content-based classification and search capabilities for Mars orbital and surface images. The deployed systems are publicly accessible using the PDS Image Atlas. We describe the process of training, evaluating, calibrating, and deploying updates to two CNN classifiers for images collected by Mars missions. We also report on three years of deployment including usage statistics, lessons learned, and plans for the future.

R&D priority-setting for global catastrophic risks: The case of the NASA planetary defense mission

"Mission-oriented" public research organizations invest in R&D to improve decision-making around complex policy problems from climate change to asteroid impacts, thus producing public value. However, the estimation of benefits produced by such R&D projects is notoriously difficult to predict and measure - a challenge that is magnified for global catastrophic risks (GCRs). GCRs are highly uncertain risks that may pose enormous negative consequences for humanity. This article explores how public research organizations systematically reduce key uncertainties associated with GCRs. Building off of recent literature highlighting the organizational and political factors that influence R&D priority-setting at public research organizations, this article develops an analytical framework for explaining R&D priority-setting outcomes that integrates the key stages of decision analysis with organizational and political dynamics identified in the literature. This framework is then illustrated with a case study of the NASA Planetary Defense Coordination Office, which addresses the GCR of near-Earth object (asteroid and comet) impacts. The case study reveals how organizational and political factors interact with every stage in the R&D priority-setting process - from initial problem definition to project selection. Lastly, the article discusses the extent to which the case study can inform R&D priority-setting at other public organizations, particularly those addressing GCRs.

Perspectives on NASA planetary programs from a mission implementation center

Perspectives on NASA planetary programs from a mission implementation center

NASA Planetary Research and Analysis: Strategy for Reorganization

NASA Planetary Research and Analysis: Strategy for Reorganization

NASA Planetary Wind Tunnel Facilities

NASA Planetary Wind Tunnel Facilities

Re-Imagining NASA Planetary Mission Science Opportunities for the next two decades

Re-Imagining NASA Planetary Mission Science Opportunities for the next two decades

NASA Planetary Research and Analysis: What is R&A?

NASA Planetary Research and Analysis: What is R&A?

The Thalassa Venus Mission Concept

The Thalassa mission concept was developed in response to the 2019 NASA Planetary Mission Concept Studies call. Using a multi-platform mission architecture, Thalassa seeks to address a single science goal: to determine the extent to which water has played a role in the geological evolution of Venus.

Dual Local Oscillator SIS Receiver for Simultaneous Observations of Water Isotopologues in the Solar System

NASA's Planetary Decadal Survey Vision and Voyages has concluded that measurements of isotopic cometary water vapor, and in particular the deuterium-to-hydrogen ratio (D/H) ratio, are an important tool for unraveling the mysteries involving the origin of Earth's water, and the evolution of our solar system. To support this goal, we have developed, through an internal Jet Propulsion Laboratory research program, quantum-limited superconductor insulator superconductor (SIS) receivers covering the important 500 $-$ 600 GHz submillimeter frequency band. These instruments can detect the (1 $_{10}$ -1 $_{01}$ ) HDO rotational transition, and the (1 $_{10}$ -1 $_{01}$ ) ground state (rotational) transitions of Ortho H $_2^{16}$ O, H $_2^{17}$ O, and H $_2^{18}$ O with exquisite sensitivity. However, given the extremely weak HDO emission and the time-variability of the outgassing processes in comets, expeditious low noise D/H ratio measurements of these sources remain extremely challenging. To address this issue, we investigate the possibility of acquiring HDO, H $_2^{17}$ O, and H $_2^{18}$ O simultaneously by means of a novel dual local oscillator (2LO) down-conversion process, as an alternative to ultra—broadband IF bandwidth systems.

Prokaryotic and Fungal Characterization of the Facilities Used to Assemble, Test, and Launch the OSIRIS-REx Spacecraft.

To characterize the ATLO (Assembly, Test, and Launch Operations) environment of the OSIRIS-REx spacecraft, we analyzed 17 aluminum witness foils and two blanks for bacterial, archaeal, fungal, and arthropod DNA. Under NASA’s Planetary Protection guidelines, OSIRIS-REx is a Category II outbound, Category V unrestricted sample return mission. As a result, it has no bioburden restrictions. However, the mission does have strict organic contamination requirements to achieve its primary objective of returning pristine carbonaceous asteroid regolith to Earth. Its target, near-Earth asteroid (101955) Bennu, is likely to contain organic compounds that are biologically available. Therefore, it is useful to understand what organisms were present during ATLO as part of the larger contamination knowledge effort—even though it is unlikely that any of the organisms will survive the multi-year deep space journey. Even though these samples of opportunity were not collected or preserved for DNA analysis, we successfully amplified bacterial and archaeal DNA (16S rRNA gene) from 16 of the 17 witness foils containing as few as 7 ± 3 cells per sample. Fungal DNA (ITS1) was detected in 12 of the 17 witness foils. Despite observing arthropods in some of the ATLO facilities, arthropod DNA (COI gene) was not detected. We observed 1,009 bacterial and archaeal sOTUs (sub-operational taxonomic units, 100% unique) and 167 fungal sOTUs across all of our samples (25–84 sOTUs per sample). The most abundant bacterial sOTU belonged to the genus Bacillus. This sOTU was present in blanks and may represent contamination during sample handling or storage. The sample collected from inside the fairing just prior to launch contained several unique bacterial and fungal sOTUs that describe previously uncharacterized potential for contamination during the final phase of ATLO. Additionally, fungal richness (number of sOTUs) negatively correlates with the number of carbon-bearing particles detected on samples. The total number of fungal sequences positively correlates with total amino acid concentration. These results demonstrate that it is possible to use samples of opportunity to characterize the microbiology of low-biomass environments while also revealing the limitations imposed by sample collection and preservation methods not specifically designed with biology in mind.

Quantum Limited SIS Receiver Technology for the Detection of Water Isotopologue Emission From Comets

NASA's Planetary Science Decadal Survey has concluded that isotopic measurements of cometary water vapor are a means to unraveling the mysteries involving the origin of Earth's water and the evolution of our solar system. To support this, a recent Jet Propulsion Laboratory internal research program has developed quantum limited superconductor–insulator–superconductor (SIS) receivers in the important 500 $-$ 600 GHz submillimeter frequency band. These instruments can be used to detect the deuterated water (HDO) ground state (1 $_{10}$ –1 $_{01}$ ), H $_2^{16}$ O ortho ground state (1 $_{10}$ –1 $_{01}$ ), and the oxygen isotopologues H $_2^{17}$ O and H $_2^{18}$ O with exquisite sensitivity. To achieve the presented results, we have investigated aluminum oxide (AlO $_x$ ) and aluminum nitride (AlN $_x$ ) barrier SIS tunnel junction mixers on the 6- $\mu$ m silicon-on-insulator substrate. The AlO $_x$ and AlN $_x$ junction mixer blocks utilize diagonal and smooth-profile conical horns, respectively. In both cases, a commercial 4–8-GHz intermediate frequency low-noise amplifier (LNA) has been integrated into the mixer block. The AlO $_x$ (low-current-density) barrier SIS junctions were fabricated with 2- $\mu$ m gold beam-lead technology, whereas in the case of the AlN $_x$ SIS tunnel junction, we use capacitive RF decoupling tabs. The latter approach simplifies fabrication, increases yield, eases the mounting process, and facilitates scaling to higher frequencies. For an actual flight mission, with operation $\leq$ 4.2 K, the allowed heat dissipation of the mixer-integrated LNA needs to be minimized. In this article, we also investigate the receiver sensitivity as a function of the LNA dc power consumption. We find that the dc power consumption of the LNA can be reduced to $\sim$ 1.6 mW with minimal loss in sensitivity. It is anticipated that the continued InP HEMT development for quantum computer applications are likely to reduce the required LNA power dissipation even further.

Fully Controlled 6 Meters per Pixel Mosaic of Mars's South Polar Region

AbstractThe Mars Reconnaissance Orbiter (MRO) spacecraft has been in operation around Mars since March 2006. The Context Camera (CTX), aboard MRO, has returned over 110,000 images of Mars at ≈5–6 m/px, providing nearly global coverage. Based on our work, reconstruction of MRO's orbit and camera pointing from ground tracking are offset from the Mars global coordinate system, with the 95th percentile of test points offset by ≈850 m, corresponding to ≈150 CTX pixels. While the original level of accuracy is potentially useful for some applications, providing relative control (image‐to‐image) and absolute or full control (image‐to‐ground reference) greatly improves the utility of the data. As a proof‐of‐concept, we have fully controlled all usable images of Mars Chart 30, Mare Australe, which is poleward of 65°S. This represents 4.7% of Mars's surface area and comprises 9,652 images (≈8% of the CTX catalog as of PDS release #48). The control was produced through a mixture of automated code and manual adjustment and validation, and mosaics were produced with manual input to provide a useful product with the best, most consistent images on top. The data—mosaics and updated SPICE kernels—are available to the community through NASA's Planetary Data System (PDS) Imaging and Cartography Annex. The workflow developed for this product is applicable to the remainder of Mars and other planetary bodies.

Availability of previously lost data and metadata from the Apollo Lunar Surface Experiments Package (ALSEP)

Fourteen types of geophysical instruments deployed at the Apollo 12, 14, 15, 16, and 17 sites by the astronauts for long-term observation were collectively called the Apollo Lunar Surface Experiments Package (ALSEP). These instruments were active from the times of their deployment (November 1969–December 1972) to September 1977. At the conclusion of the experiments, the raw instrument data received from the Moon prior to March 1976 were left unarchived. Portions of the data processed by the principal investigators (PIs) of these experiments had been archived at the NASA Space Science Data Coordinated Archive (NSSDCA) in various formats. The unarchived data, residing then on open-reel magnetic tapes, became lost in the decades since, along with much of the metadata (the supporting documents for these data). We have recently recovered 440 of the previously lost tapes, containing raw ALSEP instrument data from April through June of 1975. Here we describe the data extracted from these tapes and summarize the data products generated for archiving at the NASA Planetary Data System (PDS) and NSSDCA, along with their historical narrative. In addition, we have reformatted many of the datasets delivered to NSSDCA by the PIs in the 1970s for archiving at the PDS. Finally, we have compiled an online searchable repository of ALSEP-related documents by optically scanning tens of thousands of pages of them kept at the Lunar and Planetary Institute in Texas.

The MAVEN Radio Occultation Science Experiment (ROSE)

The Radio Occultation Science Experiment (ROSE) is part of the scientific payload of the Mars Atmosphere Volatile EvolutioN (MAVEN) spacecraft. Here we motivate the science objectives of the MAVEN ROSE investigation, which are (1) to determine the vertical structure of plasma in the ionosphere and (2) to identify the density, altitude, and width of the ionospheric density peak. MAVEN ROSE achieves these science objectives by performing two-way X-band radio occultations. Data are acquired ingress and egress opportunities using the high-gain antenna and a carrier-only signal. They are also acquired on ingress opportunities using the low-gain antenna with telemetry on the signal. Raw data are processed to yield vertical profiles of the electron density in the ionosphere of Mars with an accuracy on the order of $10^{9}\mbox{ m}^{-3}$ , a vertical resolution on the order of 1 km, and a vertical range on the order of 100–500 km. Data products are archived at the NASA Planetary Data System. In order to ensure the reproducibility of the results of the MAVEN ROSE investigation, software programs to determine MAVEN ROSE electron density profiles from time series of frequency residuals accompany this article. Furthermore, here we examine what the MAVEN ROSE observations reveal about the behavior of the ionosphere of Mars. Peak density, peak altitude, and total electron content mostly display the expected trends with solar zenith angle. However, deviations from those trends are present. Peak density at fixed dayside solar zenith angle can vary by 30% and M1 layer density at fixed solar zenith angle can vary even more. Solar irradiance variations are the most likely cause of these variations. Peak altitude at fixed dayside solar zenith angle can vary by 20 km or more. Thermospheric responses to lower atmospheric dust events are the most likely cause of these variations. Several instances of unusual ionospheric features are present in the dayside electron density profiles. A layer with density $3 \times 10^{10}\mbox{ m}^{-3}$ that appears to occur at 60 km altitude may be a horizontally-confined region of larger density that actually occurs at higher altitudes. Significant changes in density over short vertical distances around 160 km altitude may be caused by ionospheric dynamics in the presence of strong crustal magnetic fields. Topside plasma layers around 200 km altitude may reflect sharp gradients in electron temperature.

Global major-element maps of Mercury from four years of MESSENGER X-Ray Spectrometer observations

The X-Ray Spectrometer (XRS) on the MESSENGER spacecraft provided measurements of major-element ratios across Mercury's surface. We present global maps of Mg/Si, Al/Si, S/Si, Ca/Si, and Fe/Si derived from XRS data collected throughout MESSENGER's orbital mission. We describe the procedures we used to select and filter data and to combine them to make the final maps, which are archived in NASA's Planetary Data System. Areal coverage is variable for the different element-ratio maps, with 100% coverage for Mg/Si and Al/Si, but only 18% coverage for Fe/Si north of 30° N, where the spatial resolution is highest. The spatial resolution is improved over previous maps by 10–15% because of the inclusion of higher-resolution data from late in the mission when the spacecraft periapsis altitude was low. Unlike typical planetary data maps, however, the spatial resolution of the XRS maps can vary from pixel to pixel, and thus care must be taken in interpreting small-scale features. We provide several examples of how the XRS maps can be used to investigate elemental variations in the context of geological features on Mercury, which range in size from single ~100-km-diameter craters to large impact basins. We expect that these maps will provide the basis for and/or contribute to studies of Mercury's origin and geological history for many years to come.

A review of the in situ probe designs from recent Ice Giant mission concept studies.

For the Ice Giants, atmospheric entry probes provide critical measurements not attainable via remote observations. Including the 2013-2022 NASA Planetary Decadal Survey, there have been at least five comprehensive atmospheric probe engineering design studies performed in recent years by NASA and ESA. International science definition teams have assessed the science requirements, and each recommended similar measurements and payloads to meet science goals with current instrument technology. The probe system concept has matured and converged on general design parameters that indicate the probe would include a 1-meter class aeroshell and have a mass around 350 to 400-kg. Probe battery sizes vary, depending on the duration of a post-release coast phase, and assumptions about heaters and instrument power needs. The various mission concepts demonstrate the need for advanced power and thermal protection system development. The many completed studies show an Ice Giant mission with an in situ probe is feasible and would be welcomed by the international science community.

QUEST: A New Frontiers Uranus orbiter mission concept study

The ice giant planets, Uranus and Neptune, are fundamentally different from the gas giant and terrestrial planets. Though ice giants represent the most common size of exoplanet and possess characteristics that challenge our understanding of the way our solar system formed and evolved, they remain the only class of planetary object without a dedicated spacecraft mission. The inclusion of a Uranus orbiter as the third highest priority Flagship mission in the NASA Planetary Science Decadal Survey “Vision and Voyages for Planetary Science in the Decade 2013–2022” indicates a high level of support for exploration of the ice giants by the planetary science community. However, given the substantial costs associated with a flagship mission, it is critical to explore lower cost options if we intend to visit Uranus within an ideal launch window of 2029–2034 when a Jupiter gravity assist becomes available. In this paper, we describe the Quest to Uranus to Explore Solar System Theories (QUEST), a New Frontiers class Uranus orbiter mission concept study performed at the 30th Annual NASA/JPL Planetary Science Summer Seminar. The proposed QUEST platform is a spin-stabilized spacecraft designed to undergo highly elliptical, polar orbits around Uranus during a notional one-year primary science mission. The proposed major science goals of the mission are (1) to use Uranus as a natural laboratory to better understand the dynamos that drive magnetospheres in the solar system and beyond and (2) to identify the energy transport mechanisms in Uranus' magnetic, atmospheric, and interior environments in contrast with the other giant planets. With substantial mass, power, and cost margins, this mission concept demonstrates a compelling, feasible option for a New Frontiers Uranus orbiter mission.

Planetary protection technologies for planetary science instruments, spacecraft, and missions: Report of the NASA Planetary Protection Technology Definition Team (PPTDT)

Planetary bodies like Mars, Europa, and Enceladus pose the question, “How to study them without contaminating them and destroying future prospects to detect life, if it is there?” The natural trade-off, of course, is that the cleaner your spacecraft, the more you can explore such a body without risk of contaminating it. As chartered by NASA Headquarters, the Planetary Protection Technology Definition Team (PPTDT) was asked to provide a report covering six different areas related to the engineering and technology challenges of implementing planetary protection requirements on solar system exploration missions:•Assessment of technical and engineering challenges to applying available microbial-reduction methods, including recontamination prevention, to spacecraft hardware and instruments, to meet current NASA requirements on preventing the forward contamination of potentially habitable worlds by future spacecraft missions (orbiters, atmospheric missions, landers, penetrators, and drills);•Identification of spacecraft and instrument materials known to be compatible with existing planetary protection protocols;•Planetary protection protocols/processes available or which appear promising, and areas ripe for technological development;•The technical and engineering challenges in ensuring that spacecraft hardware and instruments can meet organic cleanliness requirements needed to ensure high confidence in differentiating Earth contamination from extraterrestrial signals to avoid false negative as well as false positive results;•Approaches for mitigating the identified challenges that would allow instruments to be flown successfully at the required levels of cleanliness and microbial reduction, beginning with identification of commonly used materials and spacecraft hardware that are compatible (or particularly vulnerable) to planetary protection protocols; and•Engineering, technology, and scientific research and development that could be funded by NASA to provide future capabilities to field scientific instruments and spacecraft on missions that require either subsystem or system-level microbial reduction and recontamination prevention.