A5034158044- Astro and Planetary Science
- Planetary Science and Exploration
- Space Exploration and Technology
- Geomagnetism and Paleomagnetism Studies
- Astrophysics and Star Formation Studies
- Spacecraft and Cryogenic Technologies
- Isotope Analysis in Ecology
- Ionosphere and magnetosphere dynamics
- Stellar, planetary, and galactic studies
- Solar and Space Plasma Dynamics
- Geology and Paleoclimatology Research
- Atmospheric Ozone and Climate
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Mass Spectrometry Techniques and Applications
- Astronomical and nuclear sciences
- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Earthquake Detection and Analysis
- Atomic and Subatomic Physics Research
- Magnetic confinement fusion research
- Space Satellite Systems and Control
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Gamma-ray bursts and supernovae
Southwest Research Institute
2014-2024
Saturn's moon Enceladus has an ice-covered ocean; a plume of material erupts from cracks in the ice. The contains chemical signatures water-rock interaction between ocean and rocky core. We used Ion Neutral Mass Spectrometer onboard Cassini spacecraft to detect molecular hydrogen plume. By using instrument's open-source mode, background processes production instrument were minimized quantified, enabling identification statistically significant signal native Enceladus. find that most...
Abstract The MAss Spectrometer for Planetary EXploration (MASPEX) is a high-mass-resolution, high-sensitivity, multi-bounce time-of-flight mass spectrometer (MBTOF) capable of measuring minor species with abundances sub-parts-per-million in Europa’s sputter-produced and radiolytically modified exosphere its oceanic plumes. goal the MASPEX-Europa investigation to determine, through in-situ measurement plume composition, whether conditions habitability exist or have existed on Europa. As...
Cassini's final phase of exploration The Cassini spacecraft spent 13 years orbiting Saturn; as it ran low on fuel, the trajectory was changed to sample regions had not yet visited. A series orbits close rings followed by a Grand Finale orbit, which took through gap between Saturn and its before destroyed when entered planet's upper atmosphere. Six papers in this issue report results from these phases mission. Dougherty et al. measured magnetic field Saturn, implies complex multilayer dynamo...
Cassini Ion Neutral Mass Spectrometer (INMS) measurements from roughly a hundred Titan encounters over the mission yield neutral and ion densities systematically lower, by factors approximately 2 to 3, than estimates several other spacecraft systems, including Attitude Articulation Control System, Navigation system. In this paper we present new INMS instrument sensitivity model, obtained re-analyzing (1) capture transmission of gas through instrument, (2) detector gain reduction during...
Abstract In this study, we develop a best fit description of Titan's upper atmosphere between 500 km and 1500 km, using one‐dimensional (1‐D) version the three‐dimensional (3‐D) Titan Global Ionosphere‐Thermosphere Model. For modeling, use constraints from several lower atmospheric Cassini‐Huygens investigations validate our simulation results against in situ Cassini Ion‐Neutral Mass Spectrometer (INMS) measurements N 2 , CH 4 H 40 Ar, HCN, major stable isotopic ratios 14 N/ 15 . We focus...
The sizes of Saturn's ring particles range from meters (boulders) to nanometers (dust). Determination the rings' ages depends on loss processes, including transport dust into atmosphere. During Grand Finale orbits Cassini spacecraft, its instruments measured tiny grains that compose innermost D-ring Saturn. nanometer-sized experiences collisions with exospheric (upper atmosphere) hydrogen and molecular hydrogen, which forces it fall ionosphere lower We used Magnetospheric Imaging Instrument...
Abstract We present Cassini Ion and Neutral Mass Spectrometer observations of Titan's N 2 CH 4 from flybys Titan spanning the time period 2004 to 2013 representing 9 years in situ neutral density observations. This data reveal an upward trend mixing ratios during extended solar minimum encountered prior 2011 followed by a downward after onset maximum conditions 2011. Through modeling studies using time‐dependent Global Ionosphere‐Thermosphere Model we show that this is due enhanced...
Abstract During Cassini's final, spectacular months, in situ instruments made the first direct measurements of nanoparticles, finding an exceptionally large flow from rings into Saturn's atmosphere. Ion and Neutral Mass Spectrometer measured material three altitude bands found a global‐integrated flux 2–20 × 10 4 kg/s that is dominated by hydrocarbon <10 u. Ranging clusters few molecules to radii several nanometers, nanoparticles are ubiquitous throughout but embedded regolith larger...
Abstract The Cassini Orbiter made the first in situ measurements of upper atmosphere and ionosphere Saturn 2017. Ion Neutral Mass Spectrometer (INMS) found molecular hydrogen helium as well minor species including water, methane, ammonia, organics. INMS ion mode light (H + , H 2 3 He ) Radio Plasma Wave Science instrument electron densities are presented. A photochemical analysis data indicates that major near ionospheric peak must be heavy with a short chemical lifetime. quantitative...
Abstract We present new models of Saturn's equatorial ionosphere based on the first in situ measurements its upper atmosphere. The neutral spectrum measured by Cassini's Ion and Neutral Mass Spectrometer, which includes substantial methane, ammonia, organics addition to anticipated molecular hydrogen, helium, water, serves as input for unexpectedly complex ionospheric chemistry. Heavy ions are found dominate low‐altitude ionosphere, with a mean ion mass 11 Da. Key include H 3 O + HCO ; other...
Abstract Measurements of electrons and ions in Saturn's ionosphere down to 1,500‐km altitudes as well the ring crossing region above obtained by Langmuir probe onboard Cassini spacecraft are presented. Five nearly identical deep flybys during Grand Finale orbits Final plunge orbit revealed a rapid increase plasma densities discrepancies between (N e N i ) near closest approach. The small / ratio indicates presence dusty plasma, which charge carrier is dominated negatively charged heavy...
Abstract Analysis of measurements the H 2 density in Saturn's equatorial thermosphere indicates temperatures from 340 to 370 K. The deepest measurements, obtained during Cassini's final plunge into atmosphere, measure thermospheric temperature profile. are well fit by a Bates profile with an exospheric 354 K and gradient at 1.2 × 10 −4 Pa 0.4 K/km, corresponding thermal conduction flux 7.3 −5 W/m . helium profiles consistent diffusive equilibrium. CH 4 not equilibrium but instead have...
Abstract Titan's ionosphere is created when solar photons, energetic magnetospheric electrons or ions, and cosmic rays ionize the neutral atmosphere. Electron densities generated by current theoretical models are much larger than measured instruments on board Cassini orbiter. This model density overabundance must result either from overproduction insufficient loss of ions. first two papers that examines ion production rates in ionosphere, for dayside nightside respectively. The (current)...
Abstract We present new results obtained by the Radio and Plasma Wave Science Langmuir probe on board Cassini during Grand Finale. The total direct current sampled at negative bias voltage is used to study effect of ring shadows structure Kronian topside ionosphere. D C rings Division are confirmed be optically thin extreme ultraviolet solar radiation. However, different responses from opaque A B observed. edges shadow shown match boundaries, unlike ring, which indicates variable shadow....
Abstract In 2017 the Cassini Orbiter made first in situ measurements of upper atmosphere and ionosphere Saturn. The Ion Neutral Mass Spectrometer its ion mode measured densities light species (H + , H 2 3 He ), Radio Plasma Wave Science instrument electron densities. During proximal orbit 287 (denoted P287), reached down to an altitude about 3,000 km above 1 bar atmospheric pressure level. topside plasma for P287 were consistent with ionospheric during other orbits. Spacecraft potentials by...
The MAss Spectrometer for Planetary EXploration (MASPEX) is a multi-bounce time-of-flight neutral gas mass spectrometer with unprecedented spaceborne resolution and sensitivity. It capable of measuring identifying minor trace gases requiring m/&#916;m ~ 25,000 at abundances parts-per-million in Europa&#8217;s exosphere. Exospheric sources include exsolved, sublimed, sputtered, radiolytically produced volatiles from surface interior. These can be used to characterize composition...
Abstract For orbits 288 and 292 of Cassini’s Grand Finale, clear dips (sharp narrow decreases) are visible in the <?CDATA ${{\rm{H}}}_{2}^{+}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi mathvariant="normal">H</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math> densities measured by Ion Neutral Mass Spectrometer (INMS). In 2017, southern hemisphere Saturn was shadowed its rings substructures...
&lt;p&gt;The MAss Spectrometer for Planetary EXploration (MASPEX) instrument is a multi-bounce time-of-flight mass spectrometer designed high resolution and sensitivity. MASPEX-Europa will launch as part of the Europa Clipper mission payload in October 2024 to characterize composition major, minor, trace neutral gases Europa&amp;#8217;s exosphere potential plumes. The has been optimize measurement complex natural environments with:&lt;/p&gt; &lt;ul&gt;...