A5081667727- Planetary Science and Exploration
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Spacecraft Design and Technology
- Space Science and Extraterrestrial Life
- Spacecraft and Cryogenic Technologies
- Geomagnetism and Paleomagnetism Studies
- Space Exploration and Technology
- Space Satellite Systems and Control
- Space exploration and regulation
- Methane Hydrates and Related Phenomena
- Ionosphere and magnetosphere dynamics
- Spacecraft Dynamics and Control
- Gamma-ray bursts and supernovae
- Advanced Optical Imaging Technologies
- Geology and Paleoclimatology Research
- Laser-induced spectroscopy and plasma
- CCD and CMOS Imaging Sensors
- Spaceflight effects on biology
- Distributed systems and fault tolerance
- Distributed and Parallel Computing Systems
- Neurology and Historical Studies
- Advanced Frequency and Time Standards
- Archaeological Research and Protection
- Precipitation Measurement and Analysis
Vanderbilt University Medical Center
2024
Johns Hopkins University Applied Physics Laboratory
2005-2024
Johns Hopkins University
2005-2009
University of Maryland, College Park
2005
Max Planck Society
2005
Centre National d'Études Spatiales
2005
Jet Propulsion Laboratory
2002
University of Rochester
1993
Stanford University
1960
Bedford College
1959
The Magnetospheric Imaging Instrument (MIMI) onboard the Cassini spacecraft observed saturnian magnetosphere from January 2004 until Saturn orbit insertion (SOI) on 1 July 2004. MIMI sensors frequent energetic particle activity in interplanetary space for several months before SOI. When imaging sensor was switched to its neutral atom (ENA) operating mode 20 February 2004, at approximately 10(3) times Saturn's radius RS (0.43 astronomical units), a weak but persistent signal magnetosphere....
Since 2009, the Mini-RF synthetic aperture radar (SAR) onboard NASA’s Lunar Reconnaissance Orbiter (LRO) has been collecting both S-band (12.6 cm) or X/C-band (4.2 observations to provide near-global coverage of Moon, including large portions permanently-shadowed regions. currently operates in a bistatic configuration after failure transmitter December 2010. Incident signals circular polarization are transmitted from ground stations on Earth and received by their H- V- orthogonal...
We demonstrate that the population of 20–410 keV electrons observed in Saturn's inner magnetosphere result principally from recent injections. Electrons at these energies appear to survive only up a few days neutral gas cloud emitted by jets Enceladus's southern hemisphere. Ions similar have much shorter lifetimes because charge‐exchange with ambient neutrals. been able associate fluxes different and times single past injection based on morphology electron spectrograms measurements made...
We present energetic electron data obtained by Cassini's Magnetospheric Imaging Instrument in the inner magnetosphere of Saturn. find here that inward transport and energization processes are consistent with conservation first two adiabatic invariants motion. model several injections near local midnight, one injection has a maximum energy hundreds keV, data. also mission‐averaged shows an boundary radial distance. Inward this boundary, fluxes fall off toward planet. Around strong time...
The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, launched in August 2004 planned for insertion into orbit around Mercury 2011, has already completed two flybys of the innermost planet. Dual Imaging System (MDIS) acquired nearly 2500 images from first viewed portions Mercury's surface not by Mariner 10 1974-1975. proximity to Sun its slow rotation present challenges thermal design a camera on an orbital mission Mercury. In addition, strict limitations...
We present both energetic proton and electron data from the main radiation belts of Saturn. When organized by L shell equatorial pitch angle, Cassini's Magnetospheric Imaging Instrument reveal that are highly symmetric in local time. The asymmetric two principal ways. Using close passes planet, we find for energies near a few MeV, intensity levels different between noon midnight. Furthermore, when Cassini was inbound to Saturn, fluxes dropped precipitously before spacecraft reached rings....
Abstract The Lunar CRater Observations and Sensing Satellite (LCROSS) impacted a Centaur rocket stage into permanently shadowed region (PSR) in Cabeus crater, excavating water ice other volatiles. We used the Miniature Radio Frequency (Mini‐RF) instrument on Reconnaissance Orbiter ShadowCam Korean Pathfinder to detect probable 22‐m diameter crater that resulted from LCROSS impact. formed superposed upon dense small population along ray larger pre‐existing crater. From its geologic context,...
We present evidence of two icy satellite microsignatures in the Cassini LEMMS data. Just upstream Enceladus, a deep and narrow decrease flux several MeV electrons is consistent with recent absorption by that moon. This microsignature collocated depletion proton flux. The feature much wider than diameter, suggesting multiple interactions and/or losses to E Ring neutral gas. An observed increase toward planet suggests possible inner magnetospheric source. A low energy electron intensity...
The Alzheimer's Disease Sequencing Project (ADSP) is a national initiative to understand the genetic architecture of and Related Dementias (AD/ADRD) by sequencing whole genomes affected participants age-matched cognitive controls from diverse populations. Genome Center for (GCAD) processed whole-genome data 36,361 ADSP participants, including 35,014 genetically unique which 45% are non-European ancestry, across 17 cohorts in 14 countries this fourth release (R4). This effort identified 387...
Grid image refractometry (GIR) is proposed as a technique for determining the two-dimensional density profiles of long scale-length laser-produced plasmas. Its distinctive feature that an optical probe beam broken up into ‘‘rays’’ by being passed through grid before traversing plasma. The refraction angles rays are measured imaging plasma at two or more object planes and integrated to yield phase front. For cylindrically symmetric plasmas profile then determined using Abel inversion....
This paper summarizes the architecture, capabilities, characteristics and uses of current SPICE ancillary information system, then outlines plans ideas for how this system can be extended to meet future space mission requirements.
Abstract. The spaceborne synthetic aperture radar (SAR) instruments known as Mini-RF were designed to image shadowed areas of the lunar poles and assay presence ice deposits by quantitative polarimetry. We have developed radargrammetric processing techniques enhance value these observations removing spacecraft ephemeris errors distortions caused topographic parallax so polarimetry can be compared with other data sets. Here we report on extension this capability from monostatic imaging...
A tube is described which utilizes the cyclotron motion of electrons to provide a resonant system tuned by variation magnetic flux density. The amplitude depends upon relationship applied signal frequency and electron frequency; at resonance, maximum. Resonance detected shooting spiraling through honey-comb type mesh grid; current intercepted grid greatest resonance proportional RF power. complete TRF receiver (less video amplifier) within one vacuum envelope. linear function solenoid...
The NASA Cassini spacecraft is now in orbit about Saturn and the prime phase of its mission to large moon Titan. was built managed by NASA/California Institute Technology Jet Propulsion Laboratory (JPL) Pasadena, California. Unlike previous outer planet missions, program employs a "distributed operations" approach implementing science-observing program. associated ground system implementation driven this operations concept. Under approach, science instrument teams participate directly...
The spaceborne synthetic aperture radar (SAR) instruments known as Mini-RF were designed to image shadowed areas of the lunar poles and assay presence ice deposits by quantitative polarimetry. We have developed radargrammetric processing techniques enhance value these observations removing spacecraft ephemeris errors distortions caused topographic parallax so polarimetry can be compared with other data sets. Here we report on extension this capability from monostatic imaging (signal...