Mike Gruntman

Mike Gruntman
University of Southern California | USC · Department of Astronautical Engineering

PhD, physics

About

206
Publications
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3,866
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March 1990 - present
University of Southern California
Position
  • Professor (Full)

Publications

Publications (206)
Book
Full-text available
160+ typical homework and exam problems that were given, could have been given, or should have been given (had the time allowed) in a graduate-level introductory astronautics “boot camp” course on the fundamentals of space systems at the University of Southern California (USC). More than 2,200 graduate students took this course over the last 27 yea...
Article
The idea of an “Outer solar system probe: to be aimed away from the Sun in the plane of the ecliptic” dates from a report of the “Simpson Committee” of the Space Science Board of the National Academy of Sciences in March of 1960. After many studies and name changes, what is now known as “Interstellar Probe” has matured as a concept for making new d...
Book
Full-text available
This is a personal story of a young physicist in the Soviet Union, a country distinctly different from the Western world. Mike Gruntman worked primarily in space physics and on particle detectors and science instrumentation. He was among the early pioneers in the emerging field of imaging of space plasmas in fluxes of energetic neutral atoms (ENAs)...
Article
Full-text available
Plain Language Summary Measuring the electric field in a space plasma is important for understanding how plasma flows are driven, charge particles are accelerated and heated, and how electromagnetic waves propagate. Measuring the voltage difference between two spatially separated electrodes immersed in a space plasma is one way to estimate the elec...
Article
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The Spacecraft Interaction Plasma Software package (SPIS), a three‐dimension particle in cell (PIC) code, was used to model the Parker Solar Probe (PSP) spacecraft and FIELDS instrument and their interactions with the Solar wind. Our SPIS modeling relied on material properties of new spacecraft materials that we had obtained in previous work. The m...
Article
The emission of secondary and backscattered electrons influences spacecraft surface potentials and the surrounding plasma. Modern spacecraft use new materials for which secondary emission properties have been unavailable. In this work, the total electron yield (i.e., the sum of secondary and backscattered electron yields) was measured for niobium-C...
Article
Full-text available
Exploration of the heliosphere and the far reaches of our solar system by the Voyagers and New Horizons and near-Earth observations of the Kuiper Belt and exoplanetary systems have all profoundly changed how we view our own home in space. An Interstellar Probe escaping beyond the solar-system boundaries with new observational techniques would be a...
Article
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The Soviet space port in Kazakhstan, Baikonur cosmodrome, occupies a special place in the history of rocketry and spaceflight. The first intercontinental ballistic missile R-7 successfully lifted off there in August 1957 and reached the Kamchatka peninsula six thousand kilometers away. Six weeks later, a modified R-7 placed the first artificial sat...
Article
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Electron photoemission influences spacecraft surface potentials and the surrounding plasma, and many modern spacecraft use new uncharacterized materials. The angle-dependent photoemission properties were measured for niobium C103 alloy, molybdenum TZM alloy, tantalum tungsten alloy, Elgiloy, graphite lubricant epoxy (DAG213) and titanium nitride at...
Article
Because of relative motion of the local interstellar medium (LISM) with respect to the Sun, the interstellar wind, interstellar neutral helium atoms enter the heliosphere. Instruments on the Ulysses and Interstellar Boundary Explorer spacecraft measured directional dependencies of intensities, or sky maps, of helium atoms and determined the interst...
Article
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Models of solar wind interaction with the surrounding interstellar medium usually disregard ionization of interstellar hydrogen atoms beyond the solar wind termination shock. If and when included, the effects of ionization in the heliospheric interface region are often obscured by complexities of the interaction. This work assesses the importance o...
Article
This article tells a little known story of the first anti-aircraft system SA-1 in the Soviet Union, the first nonnuclear intercept of a long-range ballistic missile, and emergence of missile defense.
Research
Full-text available
Video clips on common satellite orbits, space science, and rocket and space history
Conference Paper
Thin-film aluminum filters degrade in space with significant reduction of their Extreme Ultraviolet (EUV) transmission. This degradation was observed on the EUV Spectrophotometer (ESP) onboard the Solar Dynamics Observatory’s EUV Variability Experiment and the Solar EUV Monitor (SEM) onboard the Solar and Heliospheric Observatory. One of the possib...
Book
Full-text available
More than 50 years ago, pioneering scientists and engineers in the Soviet Union and the United States searched for a technical means of defense against ballistic missiles. This book tells the little-known story of the earliest breakthroughs which paved the way for the emergence of a powerful missile defense complex in the Soviet Union, a major fact...
Article
The expanding solar wind plasma undergoes a shock transition at the interstellar boundary of the solar system and fills the inner heliosheath, the region between the termination shock and the heliopause. The nonequilibrium heliosheath plasma is a main source of energetic neutral atoms that allow remote probing of the heliospheric interface region....
Article
Understanding of the space debris environment and accuracy of its observation-validated models are essential for optimal design and safe operation of satellite systems. Existing ground-based optical telescopes and radars are not capable of observing debris smaller than several millimeters in size. A new experimental and instrumental approach – the...
Article
Full-text available
The Interstellar Boundary Explorer (IBEX) observes the IBEX ribbon, which stretches across much of the sky observed in energetic neutral atoms (ENAs). The ribbon covers a narrow (~20°-50°) region that is believed to be roughly perpendicular to the interstellar magnetic field. Superimposed on the IBEX ribbon is the globally distributed flux that is...
Article
Full-text available
Ten years ago in the summer of 2004, the University of Southern California established a new unique academic unit focused on space engineering. Initially known as the Astronautics and Space Technology Division, the unit operated from day one as an independent academic department, successfully introduced the full set of degrees in Astronautical Engi...
Article
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The Interstellar Boundary Explorer (IBEX) returned its first five years of scientific observations from 2009 to 2013. In this study, we examine, validate, initially analyze, and provide to the broad scientific community this complete set of energetic neutral atom (ENA) observations for the first time. IBEX measures the fluxes of ENAs reaching 1 AU...
Article
The concept of a probe to the interstellar medium grew from the studies that accompanied the initial planning for a "Grand Tour" mission to the outer planets of the solar system. In 1976 a study was undertaken at the Jet Propulsion Laboratory (JPL) of an "interstellar precursor mission" as a stepping-stone from the outer solar system to interstella...
Article
Full-text available
Neutral hydrogen atoms that travel into the heliosphere from the local interstellar medium (LISM) experience strong effects due to charge exchange and radiation pressure from resonant absorption and re-emission of Lyα. The radiation pressure roughly compensates for the solar gravity. As a result, interstellar hydrogen atoms move along trajectories...
Article
Long-term ring current decay following a magnetic storm is mainly due to charge exchange collisions of ring current ions with geocoronal neutral atoms forming energetic neutral atoms (ENAs) that leave the ring current system. Therefore, the density distribution of these cold and tenuous neutral hydrogen atoms plays a key role in the ring current re...
Article
dominant neutral constituent in Earth's upper exosphere, atomic hydrogen (H), resonantly scatters solar Lyman-alpha (121.567 nm) radiation, observed as the geocorona. We report here observations of an exospheric response to geomagnetic storms obtained using measurements of the geocorona by Lyman-alpha detectors on the Two Wide-angle Imaging Neutral...
Article
Relative motion of the Sun with respect to the surrounding local interstellar medium results in entering of interstellar helium atoms into the heliosphere. Current models of helium flowing into the solar system do not include elastic collisions of atoms with solar wind ions. It was predicted in 1986, without quantitative elaboration, that such coll...
Article
The solar wind continuously flows out from the Sun and directly interacts with the surfaces of dust and airless planetary bodies throughout the solar system. A significant fraction of solar wind ions reflect from an object's surface as energetic neutral atoms (ENAs). ENA emission from the Moon was first observed during commissioning of the Interste...
Article
Full-text available
This study provides, for the first time, complete and validated observations from the first three years (2009-2011) of the Interstellar Boundary Explorer (IBEX) mission. Energetic neutral atom (ENA) fluxes are corrected for both the time-variable cosmic ray background and for orbit-by-orbit variations in their probability of surviving en route from...
Article
The recent in-situ and remote observations from the Voyager Interstellar Mission (VIM), the Interstellar Boundary Explorer (IBEX), and Ion and Neutral Camera (INCA) Cassini have revealed the interaction of the heliosphere with the very local interstellar medium (VLISM) to be much more complex than described by our present day concepts. These discov...
Article
The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission images the magnetosphere in energetic neutral atom (ENA) fluxes, which are produced in charge exchange between magnetospheric energetic ions and background exospheric hydrogen (H) atoms. To derive ion properties from ENA measurements, knowledge of the exospheric H density distrib...
Article
Full-text available
Terrestrial exospheric atomic hydrogen (H) resonantly scatters solar Lyman-α (121.567 nm) radiation, observed as the glow of the H-geocorona. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) satellites are equiped with two Lyman-α line-of-sight Detectors (LADs) each. Since during the past solar minimum conditions the relevant solar con...
Article
The ongoing Voyager Interstellar Mission (VIM) and recent observations from the Interstellar Boundary Explorer (IBEX) and Cassini missions are providing significant new information about the interaction of the heliosphere with the very local interstellar medium (VLISM). With new observations have come significant new puzzles for describing the inte...
Article
Full-text available
Exospheric atomic hydrogen (H) resonantly scatters solar Lyman- (121.567 nm) radiation, observed as the geocorona. Measurements of scattered solar photons allow one to probe time-varying three-dimensional distributions of exospheric H atoms. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission images the magnetosphere in energetic...
Chapter
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Chapter
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Article
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The Interstellar Boundary Explorer (IBEX) observes a remarkable feature, the IBEX ribbon, which has energetic neutral atom (ENA) flux over a narrow region ~20° wide, a factor of 2-3 higher than the more globally distributed ENA flux. Here, we separate ENA emissions in the ribbon from the distributed flux by applying a transparency mask over the rib...
Article
Full-text available
For many years spaceflight served as a battlefield between competing ideologies of the free world and radical socialism. A recently published compilation of declassified government documents focuses on the early history of Soviet cosmonautics. The publication details the compensation of cosmonauts and also illustrates in an unusual way economic con...
Article
Full-text available
The Rankine‐Hugoniot (R‐H) jump conditions at the heliospheric termination shock provide a means of knitting together the in situ measurements from Voyager 2 (VGR2) with the remote sensing of the heliosheath plasma via energetic neutral atom (ENA) imaging by IBEX and Cassini/INCA. The VGR2 instrument suite has a gap (∼1–30 keV) in the ion measurem...
Article
The solar output in a broad spectral range, from X-rays to ultraviolet, significantly influences the distribution of hydrogen (H) atoms in the exosphere. All three populations---ballistic, satellite, and escaping atoms---are affected by solar radiation as it modifies the effective altitude and temperature of the exobase, controls to a large degree...
Article
The Interstellar Boundary Explorer (IBEX) Mission observes a remarkable feature, the IBEX ribbon. This very narrow ~20° wide feature has energetic neutral atom (ENA) flux ~2-3 times the ENA flux that is globally distributed over other portions of the IBEX maps. Here, we separate ENA emissions in the ribbon from the globally distributed flux by appl...
Article
The first sky map of energetic neutral atoms (ENAs) from the outer heliosphere measured from the Interstellar Boundary Explorer revealed the ribbon, a remarkable circular arc of enhanced ENA emission [McComas, et al., 2009] narrow in width [Fuselier, et al., 2009] and centered at ecliptic coordinate (lambda,beta)=(221°,39°) [Funsten, et al., 2009]....
Article
The ongoing Voyager Interstellar Mission (VIM) and recent observations from the Interstellar Boundary Explorer (IBEX) and Cassini missions have revealed the interaction of the heliosphere with the very local interstellar medium (VLISM) to be much more complex than heretofore assumed by our present day concepts. These discoveries call for a major re...
Article
During a single orbit, the Interstellar Boundary Explorer (IBEX) instruments measure Energetic Neutral Atoms (ENAs) arriving at the spacecraft approximately perpendicular to the Earth/Sun line. Since IBEX spins about a Sun-centered axis, each IBEX spin yields measurements of the region of the heliopause/termination shock whose ENAs arrive within a...
Article
The Interstellar Boundary Explorer (IBEX) has obtained all-sky images of energetic neutral atoms (ENAs) emitted from the heliosheath, located between the termination shock of the solar wind and the local interstellar medium (LISM). The spectral variations over the energy range 0.3-6 keV in the ENA all-sky maps reveal an unexpected new picture of th...
Article
Full-text available
1] The first all‐sky maps of Energetic Neutral Atoms (ENAs) from the Interstellar Boundary Explorer (IBEX) exhibited smoothly varying, globally distributed flux and a narrow "ribbon" of enhanced ENA emissions. In this study we compare the second set of sky maps to the first in order to assess the possibility of temporal changes over the 6 months be...
Book
Full-text available
A part-time instructor in the University of Southern California (USC) vanished from a California beach in 1945. Several years later the U.S. Congress described him as an important Soviet spy whose true identity remained a mystery. The recently declassified documents and publications bring to light many details of the events and reveal what happened...
Chapter
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Article
The recent in situ measurements of particles and fields by Voyager 1 and 2 spacecraft and global heliospheric maps in fluxes of energetic neutral atoms (ENAs) obtained by IBEX and Cassini/INCA have challenged our established concepts of the heliosphere interaction with the surrounding local interstellar medium. We review the physics of the interact...
Article
The IBEX-Hi instrument images hydrogen ENAs from the heliosheath in 6 energy channels 0.6-6.0 keV, while Cassini/INCA extends the energy range with four more channels 6-55 keV. Both instruments produce skymaps for different energies with pixel resolution ~7°x7°. We analyze the energy-dependent spatial features in both the ENA intensity and the rela...
Article
The Interstellar Boundary Explorer (IBEX) mission has just provided the first global observations of the heliosphere's interstellar interaction [McComas et al., 2009 and other papers in the IBEX special issue of Science]. IBEX all-sky maps and energy spectra provide detailed information about this interaction. Because of the way IBEX collects its o...
Article
Interstellar Boundary Explorer (IBEX) mission gives us a unique opportunity to analyze global, three-dimensional and time-dependent, structure of the outer heliosphere. Charge exchange between interstellar neutral atoms and ions and interstellar magnetic field, through the heliopause draping, can significantly affect the topology of the heliospheri...
Article
IBEX is returning observations of energetic neutral atoms (ENAs) created in the boundary regions separating the supersonic solar wind and the pristine local interstellar medium. Underlying the interpretation of the IBEX results is the character of the proton distribution function in the inner and outer heliosheath. In particular, the proton distrib...
Article
The flux of ENAs observed by IBEX [McComas et al. 2009 and other papers in the IBEX special issue of Science] is modulated by their transit through the heliosphere. Aside from the transformation between inertial and s/c frames, the two principal effects are a reduction in flux due to photoionization and charge-exchange and a distortion of the energ...
Article
As part of the science objectives of the TWINS (Two Wide-angle Imaging Neutral-atom Spectrometers) mission, we aim to enhance the knowledge of the workings of our magnetosphere by contributing compositional information of the observed energetic neutral atom (ENA) flux from the two TWINS instruments. We will present images of oxygen (O) ENA flux var...
Article
The in-situ plasma measurements when Voyager 2 crossed the termination shock into the heliosheath revealed that only ~20% of the downstream pressure resided in the thermal ion population at energies < 30 keV at both VGRs 1 and 2 implied a partial pressure DeltaP~0.02pPa that accounted for another ~15% of the total pressure. Adding in the missing 70...
Article
The solar wind continuously flows out from the Sun, filling interplanetary space and directly interacting with the surfaces of small planetary bodies and other objects throughout the solar system. A significant fraction of these ions reflect from the surface as energetic neutral atoms (ENAs). The first ever observations of ENA emission from the Moo...
Article
Full-text available
Simulations of energetic neutral atom (ENA) maps predict flux magnitudes that are, in some cases, similar to those observed by the Interstellar Boundary Explorer (IBEX) spacecraft, but they miss the ribbon. Our model of the heliosphere indicates that the local interstellar medium (LISM) magnetic field (B(LISM)) is transverse to the line of sight (L...
Article
Full-text available
The Interstellar Boundary Explorer (IBEX) has obtained all-sky images of energetic neutral atoms emitted from the heliosheath, located between the solar wind termination shock and the local interstellar medium (LISM). These flux maps reveal distinct nonthermal (0.2 to 6 kilo–electron volts) heliosheath proton populations with spectral signatures or...
Article
Full-text available
The Sun moves through the local interstellar medium, continuously emitting ionized, supersonic solar wind plasma and carving out a cavity in interstellar space called the heliosphere. The recently launched Interstellar Boundary Explorer (IBEX) spacecraft has completed its first all-sky maps of the interstellar interaction at the edge of the heliosp...
Article
Full-text available
The Interstellar Boundary Explorer (IBEX) Science Operations Center is responsible for supporting analysis of IBEX data, generating special payload command procedures, delivering the IBEX data products, and building the global heliospheric maps of energetic neutral atoms (ENAs) in collaboration with the IBEX team. We describe here the data products...
Article
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The IBEX-Hi Neutral Atom Imager of the Interstellar Boundary Explorer (IBEX) mission is designed to measure energetic neutral atoms (ENAs) originating from the interaction region between the heliosphere and the local interstellar medium (LISM). These ENAs are plasma ions that have been heated in the interaction region and neutralized by charge exch...
Article
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The Interstellar Boundary Explorer (IBEX) is one of five Small Explorer (SMEX) missions undergoing Phase A study for NASA's Office of Space Science. Around November 2004, NASA expects to select at least one of missions for development and flight. If selected, IBEX will provide the first global views of the Sun's interstellar boundaries by taking a...
Article
Full-text available
The solar wind continuously flows out from the Sun, filling interplanetary space and impinging directly on the lunar regolith. While most solar wind ions are implanted into the lunar dust, a significant fraction is expected to scatter back and be emitted as energetic neutral atoms (ENAs). However, this population has never been observed, let alone...
Article
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The Sun, driving a supersonic solar wind, cuts out of the local interstellar medium a giant plasma bubble, the heliosphere. ESA, jointly with NASA, has had an important role in the development of our current understanding of the Suns immediate neighborhood. Ulysses is the only spacecraft exploring the third, out-of-ecliptic dimension, while SOHO ha...
Article
We present a data-analysis technique that is able to estimate the mass composition of the TWINS (Two Wide- angle Imaging Neutral-atom Spectrometers) measured energetic neutral atom (ENA) data using the amplitudes of electron distributions derived from the micro-channel plates (MCP). These distributions are generated through the registration of seco...
Article
A sun-pointed Earth-orbiting spinning spacecraft offers a convenient cost-efficient platform for global imaging the heliosphere in fluxes of energetic neutral atoms (ENAs). A single-pixel ENA instrument pointed normally to the spin axis images a full swath in the sky perpendicular to the ecliptic plane during each spacecraft rotation. As the Earth...
Article
Two satellites, TWINS-1 and TWINS-2, are presently orbiting the Earth on highly elliptic high-apogee orbits. In addition to energetic neutral atom (ENA) imagers, both satellites carry Lyman-alpha detectors (LAD). These broadband photon-counting sensors measure the line-of-sight integrated Lyman-alpha (121.6 nm) flux of solar photons resonantly scat...