Space Science Highlights
Ice Giant Systems 2020
APL researchers played a major role in organizing and participating in this international workshop focused on future exploration of the Ice Giants
Earliest Use of the Term “Habitable Zone”?
E. Walter Maunder defined the habitable zone in a popular book published in 1913.
Where do magnetospheric ions come from and how are they energized?
New observations from NASA’s MMS mission find that ions observed in the magnetotail are often of solar wind origin – and that these higher charge ions more easily attain higher energies
Energetic particles in Saturn’s magnetosphere
Plasma injections can be used to quantify the flow of mass and energy in a magnetosphere.
Asteroid Bennu’s surface is like loose, dry sand
These OSIRIS-REx observations mean that resurfacing is frequent and that Bennu’s surface is ten times younger than previously believed.
Auroral Reconstruction CubeSwarm
ARCS 2019 MIDEX
Altitude-dependent nitrogen concentrations in Venus’ atmosphere
MESSENGER-measured neutron fluxes reveal higher amount of nitrogen gas by volume at altitudes >50 km than at low altitudes.
Active/Passive Multiple Polarization Sea Ice Detection
Automated ice detection based on a new, high-resolution, synergistic algorithm provides between factors of two and eight improvement in ice edge locations, relative to ground truth, over current autom
Simulating Artificial Lunar Atmospheres
Monitoring the lunar atmosphere during and after lunar landings can help in planning missions and can address outstanding science questions.
High-Latitude Ionospheric Variability measured from Antarctica
First-principles modeling accurately predicts a major form of Space Weather at high latitudes
A New Method For Studying Exoplanet Atmospheres
Planetary Infrared Excess (PIE) could revolutionize how we study exoplanet atmospheres.
Origin of Bennu and Ryugu
The asteroids Ryugu and Bennu are aggregates born from the disruption of a large parent asteroid.
Discovery of the Mechanism Behind Saturn’s Periodic Radio Emissions and Implications for Brown Dwarfs
Temperature anisotropy in energetic particle injections leads to the generation of upper hybrid plasma waves, which in turn converts to the periodic 5 kHz radio emissions
Ion acceleration at stream interaction regions (SIRs) observed by the extraordinary measurements of Parker Solar Probe (PSP)
Parker Solar Probe is unlocking the mysteries of particle acceleration within the inner heliosphere!
Solving the Mystery of Auroral Beads
First of its kind global magnetosphere simulation undertaken at t.he APL-led Center for Geospace Storms (CGS) connects the vastly disparate scales of auroral beads and the global magnetosphere to unra
Predictive capabilities of Stream Interaction Regions at Different Solar Longitudes
A multi-point, string-of-pearl type mission architecture would improve capabilities of capturing and predicting SIRs
Juno identifies three distinct auroral acceleration zones at Jupiter
It is greatly surprising that Zone-I and Zone-II can generate equally intense auroral emissions, contrary to expectations from Earth
Why Land on Mercury?
Mercury is the only major terrestrial body for which in situ surface data are lacking, yet the planet holds unique value in understanding how rocky worlds form and evolve.
Juno discovers persistent megavolt potentials over Jupiter’s polar caps
Downward megavolt potentials (1-10 MV) fill broad regions of Jupiter’s polar caps, poleward of Jupiter’s main aurora
Investigating the formation of iron meteorites through laboratory experiments
Lab experiments that mimic the chemistry of iron meteorites provide insight into the evolution of asteroids in the early Solar System
Substorm Energy Transport from the Magnetotail to the Nightside Ionosphere
The field-aligned energy transport in the plasma sheet and subsequent deposition into the poleward boundary of the auroral bulge is most critical for substorm energy budget
Solar Illumination Dependence of the Auroral Electrojet Intensity: Interplay between the Solar Zenith Angle and Dipole Tilt
The westward auroral electrojet is more intense, probably because of higher ionospheric conductance due to more intense auroral precipitation, when the ionosphere is dark than when it is sunlit.
Major Geochemical Terranes of Mercury's Northern Hemisphere
Although not mineralogically pure end?members, individual Principal Component maps are a measure of the relative variability of pyroxenes (PC1), plagioclase (PC2), and olivine (PC3).
Impact of Deep Local Dipolarization on Electron and Ion Pitch Angle Distributions
First statistical picture of the response of electron and ion PADs to local dipolarizations inside GEO
Using Gamma-ray and Neutron “Glasses” to Measure Phobos’ Elemental Composition
By measuring the composition of Phobos, MEGANE will help resolve the question of whether Phobos is a captured asteroid or the remnants of a giant impact into Mars.
What are “negative injections” in the Earth’s magnetosphere?
These unique “negative injection” signatures are the result of the same phenomenon as the typical energetic particle injections that we’ve been studying for decades, but under different conditions.
The variable depth-to-diameter ratios of impact crater candidates on Bennu
Candidate impact craters on the tiny asteroid Bennu exhibit striking variation in depth-to-diameter ratios. These variations provides clues to the physical properties of this tiny asteroid and insight
APL Geospace Simulations at Hayden Planetarium
APL Simulations of the Geospace System Featured in a New Hayden Planetarium Show
Measuring hydrogen on Mercury using MESSENGER’s Gamma-Ray and Neutron Spectrometer
MESSENGER GRNS data reveal that more hydrogen exists in the subsurface at Mercury’s cold poles than Mercury’s hot poles.
Predicting the Geoeffective Properties of CMEs: Status, Open Issues, and Path Forward
Reliable Space Weather prediction requires targeted investment to improve observational and modeling capabilities and basic research
Probing Io’s Environment with Juno/JEDI
Io’s effect on the Jovian magnetosphere is likely mediated by wave-particle interactions.
Benchmarking Impact Hydrocodes for the DART Mission
When similar strength models are used across codes, variations in predictions for crater size and momentum enhancement from a kinetic impactor are within 15-20%.
Can EMIC waves be produced off the magnetic equator?
EMIC waves can be generated well away from the magnetic equator, given the right local conditions mainly found in the outer magnetosphere.
Anomalous Clay-Bearing Outcrop South of Valles Marineris, Mars
The identification of Fe/Mg-bearing clay layers above Al-clays means that aqueous weathering on early Mars involved multiple events and/or processes.
Energetic Oxygen and Sulfur Charge States in the Outer Jovian Magnetosphere: Insights from the Cassini Jupiter Flyby
These results indicate a charge-dependent heating/energization or an energy dependence of the charge state abundance in the outer magnetosphere of Jupiter.
How much of Mt. Sharp was fluvial?
Volume balance calculations indicate that mechanisms other than flowing water are required to account for the majority of sediments transported into Gale crater, Mars.
Understanding the Structure of the Solar Corona
Individual Images available to the public at http://sd-www.jhuapl.edu/secchi/wavelets/
Know before you go: Lunar seasons produce dynamic thermal environment in polar regions
Plans for exploration in seasonally shadowed regions should consider seasonal effects on frost stability, subsurface ice stability, and trafficability.
Solar Wind Entry Into the Magnetosphere
New APL-built model for the first time simultaneously captures both proposed mechanisms of solar wind plasma entry into the magnetosphere and suggests an explanation for the observed dawn-dusk asymme
Dragonfly: A mission to explore organic chemistry and habitability on Saturn’s moon Titan
Dragonfly will explore an ocean world to determine how far chemistry has progressed in environments providing key ingredients for life
Composition of Suprathermal Ions in Corotating Interaction Regions
The composition of CIRs exhibits clear correlation with solar activity
Don’t Judge The Moon By It’s Cover:Getting Beneath the Surface with Radar
Radar can detect variations in roughness that reveal otherwise difficult to observe features.
Contribution of bursty bulk flows to the global dipolarization of the magnetotail during an isolated substorm
Dungey cycle at work: Global substorm dipolarization of the nightside magnetosphere is an accumulation of localized geomagnetic field enhancements carried by bursty plasma flows
The largest asteroids are likely icy objects
Instead of being most similar to carbonaceous chondrites, a detailed study of large asteroids’ composition finds them to differ from those meteorites and be similar to icy asteroids like Ceres and The
Ionospheric O+ ion outflow “off the beaten path”
First observations of ionospheric O+ ion outflow directly into the nightside inner magnetosphere from an equatorial vantage point.
Comet 45P – A case of nature vs. nurture
Comet 45P retains its primitive character despite intense heating and erosion
Rocket Investigation of Current Closure in the Ionosphere (RICCI): A novel application of CubeSats from a sounding rocket platform
The RICCI mission concept uses the novel deployment of multiple CubeSats as miniature ?sub-payloads to obtain the first direct in-situ measurement of ionospheric closure currents.
Cosmic-ray Irradiation Experiments with Iron Meteorites
Psyche Gamma-Ray and Neutron Spectrometer measurements of cosmic-ray activation products are a new technique for deriving surface composition from orbit.
Defining Expected Science Value from Missions
Probabilistic science value metrics defined using information theory and operations research enable the quantification of potential “science value” of potential spacecraft missions.
The influence of collisions on ion dynamics in the inner comae of four comets
Collisions between ions and neutrals in the inner coma of a comet reduce the ion velocity and result in chemistry that changes the composition of the ions
Empirical Modeling of Extreme Space Weather Events: Storm-Time Geomagnetic Field, Electric Current, and Plasma Pressure
Application of modern data-mining and machine-learning techniques to the largest spaceborne magnetometer database enables reconstruction of the magnetic field, current and plasma pressure distributio
Floor-fractured craters on Ceres: Cryovolcanism or Solid State Flow?
New models suggest that some of Ceres' fractures on crater floors may have formed due to solid state flow of a low-viscosity, low-density material.
Is there a Europa neutral torus?
Yes, Europa is producing a neutral torus
Recent innovations at the JHUAPL Planetary Impact Lab
The JHU/APL Planetary Impact Lab developed an 3D-printed sabot for use in high-velocity gun experiments, an innovation that provides significant mass and cost savings compared to sabots manufactured u
Low Energy Precipitating Electrons in the Diffuse Aurorae
High fluxes of low energy electrons observed by the DMSP can be attributed to the secondary electrons that bounce between the conjugate points in the ionosphere.
Areas With Unusual Ultraviolet SignaturesDiscovered on the Moon
Investigation of anomalous FUV regions may help in the understanding of lunar surface processes, including the formation of lunar swirls.
3D Reconstruction of Coronal Mass Ejections (CMEs) and Their Shocks
Multi-viewpoint coronal imaging allows the extraction of the 3D properties of CMEs and shocks and the assessment of their potential for Space Weather.
Mars: Composition Beneath the Dust
Composition of the youngest rocks are comparable to intermediate-aged volcanic terrain. The mostancient volcanic material is compositionally distinct, suggesting early igneous evolution of the crust.
Measuring Earth radiation with the RAVAN CubeSat
RAVAN demonstrates new technologies that enable future Earth radiation budget (ERB) measurements and establishes a benchmark for an ERB small satellite constellation.
Storm-Driven Rebuilding and Intensification of Earth's Radiation Belt
Geomagnetic storms can act as a "reset" button for the outer radiation belt. At storm onset, the existing outer belt is largely annihilated and a new, more intense belt is rebuilt. New APL-built mode
Bennu asteroid map
OSIRIS-REx explores why asteroid Bennu doesn't break apart?
What is the Origin of Daytime Auroral Pulsations?
Daytime Pc3 auroral pulsations are directly linked to upstream-generated compressional Pc3 waves and their modulations of chorus waves and keV electrons in the outer magnetosphere
Small Body Mapping Tool
Make your own asteroid maps!
Mercury: The view after MESSENGER
Compendium of Science from MESSENGER Just Published!
How many near-Earth asteroids have water in their minerals?
Water on asteroids is more accessible than water on the moon.
Recurrent Formation of a Dawnside Electric Current System During Geomagnetic Storms
An intense auroral current system forms recurrently on the dawn side during major geomagnetic storms causing large magnetic disturbances at midlatitudes.
The First Multi-Viewpoint Catalog of Coronal Mass Ejection (CME) Properties
The first-ever ‘stereoscopic’ catalog of CME properties (based on simultaneous 2 viewpoint observations from the STEREO mission).
The Dynamics of Crater Ejecta Emplacement
Crater ejecta slides violently away from the crater after landing, eroding and shearing the surface and subsurface to significant depths.
High-Energy Particle Transport and Acceleration at Earth
Magnetic trapping enables transport and energization of energetic ions and relativistic electrons deep into the near-Earth space
The case for seasonal surface changes at Titan's lake district
Titan’s north polar lakes experience seasonal shoreline change.
Sources of Plasma at Saturn
Two important processes contribute to solar wind particle entry into the magnetosphere of Saturn
The curious case of a missing meteoritic signature
Two impact craters in Canada formed in nearly identical targets have starkly different meteoritic signatures.
Improved Lunar Prospector Neutron Spectrometer Map
Reconstruction of Lunar Prospector thermal neutron data reveal 100 km sized regions of nearly pure anorthosite in basins on the lunar farside.
What can Apollo soil samples tell us about the Moon’s environment?
The physical, chemical, and spectral properties of lunar agglutinates hold clues about the space weathering processes that formed them.
Modeling impact outcomes for the Double Asteroid Redirection Test (DART) Mission
Material porosity and internal structure can significantly affect crater shape, ejecta field, and momentum enhancement from a kinetic impactor.
Wind-sculpted Landscape on Olympus Mons, Mars
The Olympus Maculae reveal multiple episodes of wind-driven deposition and erosion, suggesting fluctuating atmospheric conditions in the Late Amazonian.
Antarctica Balloon Flight Tests New Science Instruments
High-altitude balloon flights provide a cost-effective means to test planetary gamma-ray and neutron spectrometers in a space-like radiation environment.
A proxy for solar wind conditions near Mars
The proxy we derive for magnetic field direction upstream of Mars will be useful when MAVEN’s orbit gets lowered such that it goes into the solar wind less often.
Projectile preservation during oblique impacts
Oblique impacts significantly enhance projectile preservation. The results suggest a new strategy for sample return missions that rely on impact capture. Moreover, our findings imply that M-type aster
Red sand, Blue sand
The color of sand on Mars’ dunes depends on grain size, composition, and oxidation state.
The delivery of water by impacts
Water delivered by impactors can be trapped in significant quantities within impact glasses and melt-bearing breccias, thereby contributing to the early accretion of water during planet formation.
Methane Rain Clouds at Titan
Titan's weather patterns suggest liquid methane reservoirs below the surface near Titan's poles.
Atmospheric drag is eroding Saturn’s inner ring
More than ten tons of molecules and small neutral particles every second are flowing into Saturn from its rings because of the interaction between Saturn’s atmosphere and the rings.
How did Mercury get its ice?
The Hokusai impact could be the source of Mercury’s water ice.
Investigating the Ages of Mercury’s Explosive Volcanic Deposits
Explosive volcanism on Mercury extended into Recent Geologic History, well after the presumed cessation of volcanic activity early in Mercury’s history.
Asteroid shapes from disruption and reaccumulation
Energetic disruption and reaccumulation produces top-shaped asteroids. More elongated asteroids like Eros and Itokawa form less commonly.
MESSENGER Advanced Products (MEAPs)
The MESSENGER Advanced Product (MEAP) project enhances the utility of MESSENGER data from the planet Mercury to the planetary science community.
Identifying buried, compositionally-distinct materials on Mars using gamma-ray measurements
Gamma-ray measurements can reveal the presence of compositionally-distinct deposits buried several 10s of cm below Mars’ surface.
Prebiotic Molecules Storage in Comets
The remarkable chemical diversity of comets reflects the range of conditions in the early Solar System
The APL Planetary Impact Lab
The APL Planetary Impact Lab (PIL) includes a Vertical Gun Range and Ejecta Catapult that enable state-of-the-art studies of impact cratering processes.
Mapping Ice at Mercury’s South Pole
The uneven distribution of Mercury’s ice supports a comet impact origin
An exogenic origin for Iapetus’ ridge
A collapsing disk of debris could build topography to create a ridge around Iapetus
Impact Melting on Vesta at the Rheasilvia Antipode
Giant impact melting may have prolonged igneous activity on protoplanets
Effect of Re-impacting Debris on the Solidification of the Lunar Magma Ocean
Debris generated after the Moon-forming impact would have re-impacted the Moon, introducing additional heat transfer mechanisms to the conventional conductive-lid scenario.
Mercury’s Dark Secret
Low Reflectance Material on Mercury is enriched in carbon, and is native to Mercury.
Evidence for volatiles on the surface of 433 Eros and 1036 Ganymed
We have detected hydrated minerals on the two largest near-Earth asteroids, expected to be anhydrous. They likely are delivered by external sources such as solar wind or dust.
A Fresh Look at Older Mars Odyssey Neutron Spectrometer Data Yields a Surprise at the Equator
An improved-resolution map of the MONS epithermal neutron data was created and reveals substantial, unexpected H deposits near the equator.
Mars: Destroyer of Sand Dunes
Mars’ current climate may be eroding away the most upwind sand dunes