A5033190725- Astro and Planetary Science
- Planetary Science and Exploration
- Stellar, planetary, and galactic studies
- Space Exploration and Technology
- Isotope Analysis in Ecology
- Solar and Space Plasma Dynamics
- Astrophysics and Star Formation Studies
- Geomagnetism and Paleomagnetism Studies
- Atmospheric Ozone and Climate
- Ionosphere and magnetosphere dynamics
- Spacecraft and Cryogenic Technologies
- Space Science and Extraterrestrial Life
- Astronomy and Astrophysical Research
- Geology and Paleoclimatology Research
- Scientific Research and Discoveries
- Methane Hydrates and Related Phenomena
- Space exploration and regulation
- Nuclear Physics and Applications
- Spaceflight effects on biology
- Atomic and Molecular Physics
- Nuclear physics research studies
- Astronomical and nuclear sciences
- Mass Spectrometry Techniques and Applications
- Calibration and Measurement Techniques
- Paleontology and Stratigraphy of Fossils
Goddard Space Flight Center
2021-2025
Johns Hopkins University Applied Physics Laboratory
2017-2024
Laboratory for Atmospheric and Space Physics
2023
Southwest Research Institute
2010-2021
Jet Propulsion Laboratory
2021
Allentown Public Library
2020-2021
Johns Hopkins University
2018-2021
Max Planck Society
2018
The University of Texas at San Antonio
2010-2017
Harford Community College
2012
The geologic origin of the Medusae Fossae Formation (MFF) has remained a mystery despite three decades research. To better constrain its formation, an in‐depth analysis observations made in literature was combined with new survey over 700 Mars Orbiter Camera narrow‐angle images MFF to identify morphologic characteristics and material properties that define this formation as whole. While previous work identified clear agreement on some characteristics, our identifies yardangs, collapse...
Abstract We discuss observations of the journey throughout Solar System a large interplanetary coronal mass ejection (ICME) that was ejected at Sun on 14 October 2014. The ICME hit Mars 17 October, as observed by Express, Atmosphere and Volatile EvolutioN Mission (MAVEN), Odyssey, Science Laboratory (MSL) missions, 44 h before encounter planet with Siding‐Spring comet, for which space weather context is provided. It reached comet 67P/Churyumov‐Gerasimenko, perfectly aligned 3.1 AU, Rosetta...
The existence of methane in Titan's atmosphere (∼6% level at the surface) presents a unique enigma, as photochemical models predict that current inventory will be entirely depleted by photochemistry timescale ∼20 Myr. In this paper, we examine clues available from isotopic ratios (12C/13C and D/H) to past history species. We first analyze recent infrared spectra CH4 collected Cassini Composite Infrared Spectrometer, measuring simultaneously for time abundances all three detected minor...
We propose to identify the main sources of ionization plasma in coma comet 67P/Churyumov–Gerasimenko at different locations and quantify their relative importance, for first time, close cometocentric distances (<20 km) large heliocentric (>3 au). The ionospheric model proposed is used as an organizing element a multi-instrument data set from Rosetta Plasma Consortium (RPC) particle sensors, Orbiter Spectrometer Ion Neutral Analysis Microwave Instrument on Orbiter, all board ESA/Rosetta...
Abstract Jupiter’s icy moon, Europa, harbors a subsurface liquid water ocean; the prospect of this ocean being habitable motivates further exploration moon with upcoming NASA Europa Clipper mission. Key among mission goals is comprehensive assessment moon’s composition, which essential for assessing Europa’s habitability. Through powerful remote sensing and in situ investigations, will explore composition surface subsurface, its tenuous atmosphere, local space environment surrounding moon....
Jupiter's moon Io hosts extensive volcanism driven by tidal heating. The isotopic composition of Io's inventory volatile elements, including sulfur and chlorine, reflects its outgassing mass loss history provides an avenue for exploring evolution. We used millimeter observations atmosphere to measure isotopes in gaseous SO2 SO, chlorine NaCl KCl. find $^{34}$S/$^{32}$S=0.0595$\pm$0.0038 ($\delta^{34}$S=+347$\pm$86 per mille), which is highly enriched compared average Solar System values...
The origin of Titan's nitrogen-rich atmosphere is thought to be ammonia ice, but this has not yet been confirmed. Furthermore, it uncertain whether the building blocks Titan formed within Saturnian subnebula or in colder protosolar nebula (PSN). Recent measurements nitrogen isotope ratio cometary ammonia, combined with evolutionary constraints on isotopes provide firm evidence that must have originated as ice PSN under conditions similar formation. This result important implications for...
We use measurements from the Rosetta plasma consortium (RPC) Langmuir probe (LAP) and mutual impedance (MIP) to study spatial distribution of low-energy in near-nucleus coma comet 67P/Churyumov-Gerasimenko. The is highly structured with highest density summer hemisphere above region connecting two main lobes comet, i.e. neck region. There a clear correlation neutral ratio found be about 1-2x10^-6, at cometocentric distance 10 km 3.1 AU sun. A 6.2 h modulation seen as exposed twice per...
Context. The Rosetta spacecraft is escorting comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 AU, where the activity was low, until perihelion at 1.24 AU. Initially, solar wind permeates thin atmosphere formed sublimation.
[1] The Cassini-Huygens mission has been observing Titan since October 2004, resulting in over 70 targeted flybys. Titan's thermosphere is sampled by the Ion and Neutral Mass Spectrometer (INMS) during several of these measured upper atmospheric density varies significantly from pass to pass. In order quantify processes controlling this variability, we calculate nitrogen scale height for a variety parameters related solar plasma environments and, these, infer an effective temperature....
We have re-evaluated the Cassini Ion Neutral Mass Spectrometer (INMS) 12C/13C ratios in upper atmosphere of Titan based on new calibration sensitivities and an improved model for NH3 background 13CH4 mass channel. The INMS measurements extrapolated to surface give a CH4 88.5 ± 1.4. compare results revised ratio 91.1 1.4 provided by Huygens Gas Chromatograph 86.5 7.9 Infrared determine implications evolution methane Titan's atmosphere. Because measured is within probable range primordial...
The Cassini Ion Neutral Mass Spectrometer (INMS) has measured both neutral and ion species in Titan's upper atmosphere ionosphere the Enceladus plumes. densities derived from INMS measurements are essential data for constraining photochemical models of ionosphere. objective this paper is to present an optimized method converting raw by densities. To do this, we conduct a detailed analysis ground in‐flight calibration constrain instrument response energy, critical parameter on which based....
Context. Early measurements of Rosetta's target comet, 67P/Churyumov-Gerasimenko (67P), showed a strongly heterogeneous coma in H2O, CO, and CO2.
Abstract The Rosetta spacecraft has escorted comet 67P/Churyumov‐Gerasimenko since 6 August 2014 and offered an unprecedented opportunity to study plasma physics in the coma. We have used this make first characterization of cometary electrons with kappa distributions. Two three‐dimensional functions were fit observations, which we interpret as two populations dense warm (density = 10 cm −3 , temperature 2 × 5 K, invariant index 10−>1000), rarefied hot 0.005 1–10) electrons. observations...
One of the primary objectives Rosetta Plasma Consortium, a suite five plasma instruments on-board spacecraft, is to observe formation and evolution interaction regions at comet 67P/Churyumov-Gerasimenko (67P/CG). Observations made between 2015 April 2016 February show that solar wind–cometary boundaries formed around mid-April lasted through early January. At least two were observed, separated by an ion-neutral collisionopause boundary. The inner region was located on nucleus side boundary...
The Moon is generally depleted in volatile elements and this depletion extends to the surface where most abundant mineral, anorthite, features <6 ppm H2O. Presumably other nominally anhydrous minerals that dominate mineral composition of global surface—olivine pyroxene—are similarly water volatiles. Thus tabula rasa for study volatiles introduced wake its origin. Since formation last major basin (Orientale), from solar wind, impactors all sizes, expelled interior during volcanic eruptions...
During the course of its evolution, our Sun and protective magnetic bubble have plowed through dramatically different interstellar environments throughout galaxy. The vast range conditions plasma, gas, dust high-energy cosmic rays on this "solar journey" helped shape solar system that we live in. Today, bubble, or Heliosphere, is likely about to enter a completely new regime space will, yet again, change entire heliospheric interaction how it shields us from environment. Interstellar Probe...