SEARCH · Search NASA

Results for “Interstellar”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16

All sources NASA NTRS DOE OSTI

NASA NTRS2015

Laboratory Studies of Cosmic Dust with NASA Ames' COSmIC Facility – Applications to Interstellar and Planetary Issues

I will present and discuss the unique characteristics and capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to generate, process and analyze interstellar, circumstellar and planetary analogs in the laboratory. COSmIC stands for Cosmic Simulation Chamber and is dedicated to the study of molecules and ions under the low temperature and high vacuum conditions that are required to simulate interstellar, circumstellar and planetary physical environments in space. COSmIC integrates a variety of state-of-the-art instruments that allow forming, processing and monitoring simulated space conditions for planetary, circumstellar and interstellar materials in the laboratory. COSmIC is composed of a Pulsed Discharge Nozzle (PDN) expansion that generates a free jet supersonic expansion coupled to two ultrahigh-sensitivity, complementary in situ diagnostics: a Cavity Ring Down Spectroscopy (CRDS) system for photonic detection and a Reflectron Time-Of-Flight Mass Spectrometer (ReTOF-MS) for mass detection. Recent, unique, laboratory astrophysics results that were obtained using the capabilities of COSmIC will be discussed, in particular the progress that have been achieved in deciphering the diffuse interstellar bands (DIBs) and in monitoring in the laboratory the formation of solid dust grains from their gas-phase molecular precursors in environments as varied as stellarcircumstellar outflow and planetary atmospheres. Plans for future, next generation, laboratory experiments on cosmic molecules and grains in the growing field of laboratory astrophysics will also be addressed as well as the implications of these studies for current and upcoming space missions.

COSmIC↗

NASA NTRS2016

The Past and Future of AstroPAH Research and the Diffuse Interstellar Bands

Here, we present a critical assessment of the PAHs as DIB Carriers and discuss the progress and the advances that have been achieved so far through a series of complementary studies involving astronomical observations of DIBs, laboratory simulation of interstellar analogs for PAHs (neutrals and ions), space exposure experiments of PAHs, theoretical calculations of PAH spectra and the modeling of diffuse and translucent interstellar clouds. We will discuss what we have learned from these complementary studies, the constraints that can be derived from these studies for the PAHs as DIB carriers and the future studies that are required to address the open questions. These involve extending the laboratory and astronomical PAH-DIB studies from the NUV-Visible range into the NIR and MIR domains where DIBs have also been observed and developing tools in the laboratory to help generate more complex, PAH-related species for comparison with astronomical data. For the laboratory part, we will present the COSmIC facility at NASA-Ames that provides experimental conditions that closely mimic the interstellar conditions and helps address these issues. The comparison of astronomical data with laboratory data measured under realistic conditions is the only way to derive clear and unambiguous conclusions regarding the expected abundances for PAHs of various sizes and charge states in interstellar environments. From the observational aspect we will explore the new opportunities offered by JWST to connect the DIBs to MIR PAH emission and to search for NIR DIBs that may trace the presence of PAHs.

Salama, Farid↗

NASA NTRSDate not supplied

Researching the Planetary Environment with an Interstellar Probe

In 2018, a study originated with the idea of a mission that would be feasible to launch in the 2030s, targeting 1000 AU within 50 years using current technology. While the primary objective of such an Interstellar Probe would be to understand the heliosphere and interstellar medium, this probe offers an excellent opportunity for rock, dust, and ice sciences. In the initial stages of its journey through the solar system, this Interstellar Probe would carry out a wide range of potential observations to study the planetary environment, particularly focusing on dust/ice analysis and planetary science through fly-bys of critical science targets, especially in the trans-Neptunian region. A flyby of a trans-Neptunian dwarf planet, such as Quaoar, would provide further geological, compositional, and geophysical context for Earth-based observations. Aside from in-situ remote sensing techniques, VISIR and dust analyses would also benefit in this region of the solar system to determine (i) dominant ice and dust compositions and potential variations depending on heliocentric distance (e.g., chemical or irradiated products); (ii) collections and identification of PAH-type components; and (iii) solar nebula chemical and mechanical processing, such as collisions. The purpose of our poster is to provide a background of the Interstellar Probe’s objectives and possible instrumentation to offer insight on current questions about the planetary environment.

C J Ahrens↗

NASA NTRS2019

The Characterization of Secondary Interstellar Neutral Oxygen Beyond the Heliopause: A Detailed Analysis of the IBEX-Lo Oxygen Observations

In this study, we analyze the directional distribution of the secondary interstellar neutral (ISN) O population observed by the IBEX-Lo neutral atom camera on the Interstellar Boundary EXplorer (IBEX) via the comparison with simulated ISN O intensity maps produced by an analytical model. In the analytical model, we assume that there are primary and secondary ISN populations at the heliopause. We further assume that each population is represented by a Maxwellian velocity distribution function with its own flow parameters. For the viewing directions of IBEX-Lo, we compute the incoming atom speeds at the heliopause with a Keplerian equation of motion in the solar gravity field. Then, we calculate analytically the distribution function to obtain the ISN intensities at Earth’s orbit. We compare the simulated O intensity maps with the IBEX-Lo O sky map to determine the most likely flow parameters of the secondary ISN O population. Using this method, we find the most likely flow parameters of the secondary ISN O population: V(sub SecISNO) = 11 ± 2.2 km s(exp -1), λ(sub SecISNO) = 67° ± 1°.5, β(sub SecISNO) = -12° ± 1°.6, and T(sub SecISNO) = 10,000 ± 1500 K. The results indicate that the secondary ISN O flow direction is deflected toward lower ecliptic longitude and higher negative ecliptic latitude from the ISN gas flow direction at the heliopause. The secondary ISN O flow direction is more deflected from the ISN gas flow direction than the secondary ISN He flow direction.

Interstellar matter clouds↗

DOE OSTI2026

The Interstellar Mapping And Acceleration Probe High Energy (IMAP-Hi) Neutral Atom Imager

The IMAP-Hi Energetic Neutral Atom (ENA) Imager on NASA’s Interstellar Mapping and Acceleration Probe (IMAP) mission (McComas et al. 2018a, 2025) is designed to measure ENAs from the global interaction between the heliosphere and the local interstellar medium (LISM). These ENAs are initially plasma ions of solar wind origin that are neutralized by charge exchange with the cold neutral atoms of LISM that freely flow through the heliosphere-LISM interaction region. IMAP-Hi consists of two identical single-pixel sensors, each covering the ENA spectral range from 0.44 keV to 15.6 keV over nine contiguous energy passbands and having an approximately conical field-of-view (FOV) of 4.1o full width at half maximum (FWHM). The Hi-45 sensor points 45o relative to the spacecraft spin axis from the antisunward direction; each spacecraft spin, it measures ENA intensity over a circular swath with half-cone angle 45o centered on the ecliptic plane. The Hi-90 sensor points 90o relative to the spin axis; each spacecraft spin, it measures ENA intensity over a great circle in the sky, sampling both the north and south ecliptic poles. As the IMAP spin vector is re-pointed daily toward the Sun, the ecliptic longitude of the swaths moves daily by ∼1o such that a full sky map is acquired by Hi-90 every six months and a complete low latitude (−45o to +45o) map is acquired by Hi-45 annually. The IMAP-Hi sensor design has direct heritage from the IBEX-Hi imager on the Interstellar Boundary Explorer (IBEX) mission, with substantial improvements in energy range, energy resolution, angular resolution, signal-to-noise ratio, and, for ecliptic latitudes within ±45o, temporal resolution and exposure time. The global ENA maps acquired by IMAP-Hi partially overlap in energy and viewing with the ENA maps acquired by the IMAP-Lo and IMAP-Ultra ENA imagers, which we combine to answer fundamental questions about the structure and dynamics of the interaction of the heliosphere and the LISM.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1966

Interstellar molecule formation

Interstellar molecule formation by chemical exchange reactions between interstellar gas atoms and atoms chemically bound to interstellar grains

MOLECULAR FORMING↗

NASA NTRS1966

Interstellar molecule formation.

Interstellar molecule formation as result of chemical exchange reactions between atoms of interstellar gas and atoms chemically bound to interstellar grains

INTERSTELLAR MATERIAL↗

NASA NTRS2014

Interstellar Organics, the Solar Nebula, and Saturn's Satellite Phoebe

The diffuse interstellar medium inventory of organic material (Pendleton et al. 1994, Pendleton Allamandola 2002) was likely incorporated into the molecular cloud in which the solar nebula condensed. This provided the feedstock for the formation of the Sun, major planets, and the smaller icy bodies in the region outside Neptune's orbit (transneptunian objects, or TNOs). Saturn's satellites Phoebe, Iapetus, and Hyperion open a window to the composition of one class of TNO as revealed by the near-infrared mapping spectrometer (VIMS - Visible and Infrared Mapping Spectrometer) on the Cassini spacecraft at Saturn. Phoebe (mean diameter 213 kilometers) is a former TNO now orbiting Saturn. VIMS spectral maps of Phoebe's surface reveal a complex organic spectral signature consisting of prominent aromatic (CH) and aliphatic hydrocarbon (CH2, CH3) absorption bands (3.2-3.6 meters). Phoebe is the source of a huge debris ring encircling Saturn, and from which particles (5-20 meter size) spiral inward toward Saturn. They encounter Iapetus and Hyperion where they mix with and blanket the native H2O ice of those two bodies. Quantitative analysis of the hydrocarbon bands on Iapetus demonstrates that aromatic CH is 10 times as abundant as aliphatic CH2 plus CH3, significantly exceeding the strength of the aromatic signature in interplanetary dust particles, comet particles, and in carbonaceous meteorites (Cruikshank et al. 2013). A similar excess of aromatics over aliphatics is seen in the qualitative analysis of Hyperion and Phoebe itself (Dalle Ore et al. 2012). The Iapetus aliphatic hydrocarbons show CH2/CH3 4, which is larger than the value found in the diffuse ISM (InterStellar Matter - (2-2.5). Insofar as Phoebe is a primitive body that formed in the outer regions of the solar nebula and has preserved some of the original nebula inventory, it can be key to understanding the content and degree of processing of that nebular material. There are other Phoebe-like TNOs that are presently beyond our ability to study in the organic spectral region, but JWST (James Webb Space Telescope) will open that possibility for a number of objects. We now need to explore and understand the connection of this organic-bearing Solar System material to the solar nebula and the inventory of ISM (Interstellar Medium) materials incorporated therein.

Phoebe↗

NASA NTRSDate not supplied

Materials and technologies for interstellar flights and intra-galactic spread of life

Small automated spaceships are capable to deliver seeds, frozen ova and gametes to other planetary systems. A spaceship can be equipped with a freezer containing reproductive cells, an artificial uterus, a robotic nursery and school, and a collection of instruments and equipment. The whole spaceship will be frozen during a long interstellar flight. Approaching another star, a spaceship will generate electricity from light, warm up, slow down and land on a suitable planet (if any), give birth to a human, provide care and education. After schooling, the human will vacate the spaceship and either build more space for living (using local materials) or die. A vacant spaceship will supply more people, one at a time. Hopefully, they will collectively create a sustainable colony on a remote planet. Our Milky Way galaxy has hundreds billion stars (i.e., more stars than humans on Earth). Mass production of spacecrafts for intragalactic spread of life will make each spaceship cheaper, will improve employment and purposeful production on Earth, and will spread human life beyond the Solar System. If any spaceship will miss its target stellar system, it will fly to the next one, retaining ability to bring life to another planet. Which materials and technologies are needed for the interstellar life propagation? Materials age during a long interstellar flight, which can last from 10^4 to 10^10 years. We evaluate the computational methods (such as C2NEB, available from https://lib.dr.iastate.edu/ameslab_software/1) that are suitable for addressing materials aging at low temperatures and high radiation levels during the appropriately long-time scales.

Technologies↗

NASA NTRS1996

The Voyager Interstellar Mission

The Voyager Interstellar Mission began on January 1, 1990, with the primary objective being to characterize the interplanetary medium beyond Neptune and to search for the transition region between the interplanetary medium and the interstellar medium...This paper describes the Voyager Interstellar Mission - the mission objectives, the spacecraft and science payload, the mission operations strategy being used to maximize science data return even in the event of certain potential spacecraft subsystem failures.

Voyager↗

NASA NTRS1994

Electron Density Power Spectrum in the Local Interstellar Medium

Interstellar scintillation (ISS), fluctuations in the amplitude and phase of radio waves caused by scattering in the interstellar medium, is important as a diagnostic of interstellar plasma turbulence. ISS is also of interest because it is noise for other radio astronomical observations.

interstellar↗

NASA NTRS2024

Interstellar Propulsion

As you read this, humanity’s first interstellar probe has left our solar system and is moving at nearly 17 km/s on its journey through interstellar space. Launched in 1977 and carrying a message from Earth on an inscribed golden disk, Voyager 1 completed its grand tour of the outer planets and has since travelled more than 24 billion km on its outward journey; it’s twin probe, Voyager 2, has also left the heliopause and entered interstellar space, traveling over 20 billion km from Earth. Yet even at these speeds and distances, our intrepid Voyagers have barely moved beyond the influence of our local star. If the distance between our Sun and the closest neighboring star system, Alpha Centauri, were scaled to the size of a meter stick, Voyager 1 would be located just over the ½-mm mark, having traveled 0.06% of the way to the next star (assuming it was pointed in the right direction, which it isn’t). At this rate it will take the probe nearly 75 thousand years to cover the equivalent distance to Alpha Centauri.

Interstellar↗

NASA NTRS1972

Preliminary results on interstellar reddening as deduced from filter photometry

Filter photometry has been used to derive the interstellar reddening law from stars through the study of a single spectral type, B0. The deficiency in the far ultraviolet flux of a supergiant relative to a main sequence star is compared with the difference in the flux distribution due to a change of one spectral class. Individual interstellar reddening curves show the general feature reported by Stecher (1969) and by Bless and Savage (1970). There is a large amount of scatter in the far ultraviolet which may be partially due to a real difference in interstellar extinction and partially due to observational inaccuracy.

Laget, M.↗

NASA NTRS1972

Interstellar medium model

A model of the ionized part of the interstellar medium was developed, based on the low frequency observations by the Radio Astronomy Explorer Satellite with a background of nonthermal radiation. This nonthermal background radiation is caused by synchrotron emission from cosmic ray electrons, and at low frequencies this emission is heavily absorbed by free-free absorption from the residual thermal electrons in the interstellar medium. By an appropriate model, parameters relevant to both the thermal and nonthermal components of the interstellar medium are shown. The observations were taken with the 100 deg dipole antenna and separated into galactic and extragalactic components. This model was developed using only the separated galactic component.

Novaco, J. C.↗

NASA NTRS1972

The influence of the ionized medium on synchrotron emission in interstellar space.

The effect of the ionized gas on synchrotron emission in the interstellar medium is investigated. A detailed calculation of the synchrotron emissivity of cosmic electrons, assumed to have an isotropic pitch-angle distribution in a uniform magnetic field, is made as a function of frequency and observation angle with respect to the field. The results are presented both as a local emissivity and as an intensity, the latter obtained by neglecting free-free absorption in the interstellar medium and by assuming that the emissivity is constant along the line of sight. The comparison of these results with previous studies on the nature of the low-frequency turnover of the galactic nonthermal radio background reveals that, except if the component perpendicular to the line of sight of the interstellar magnetic field is small (less than 1 microgauss), or if the cosmic-ray electron spectrum is cut off at energies below a few hundred MeV, the suppression of synchrotron emission by the ambient electrons has in general a lesser effect than free-free absorption by these electrons, and that in some cases this suppression effect is almost entirely negligible.

Ramaty, R.↗

NASA NTRS1972

Interstellar circular polarization.

This paper shows that optical observations of circular polarization produced by aligned interstellar grains could yield valuable information about the grain material. The interstellar medium is known to be linearly dichroic from observations of interstellar linear polarization. Since the same aligned grains make the medium linearly birefringent, a small component of circular polarization can result from incident linearly polarized light if the position angle of the linear polarization does not coincide with either principal axis of the medium. Calculations demonstrate that the wavelength of the circular polarization is sensitive to the imaginary part of the complex refractive index of the grain material. This provides an opportunity of investigating whether the grains are characteristically dielectric or metallic.

Martin, P. G.↗

NASA NTRS1973

A study of cosmic-ray positron and electron spectra in interplanetary and interstellar space and the solar modulation of cosmic rays

The differential energy spectra of cosmic-ray positrons and negatrons with energies between approximately 11 and 1500 MeV was measured during the period 1968-1971 using a balloon-borne magnetic spectrometer. These measurements fill a gap in the previously existing data and permit the determination of the interstellar spectra of cosmic-ray positrons and electrons. Knowledge of these spectra provides a crucial tool for studies of the distribution and density of matter and magnetic fields in the interstellar medium and the origin and dynamics of energetic particles contained in the fields. The differential energy spectrum of interstellar electrons may be represented as a power-law, j alpha T to the -1.8 power for 100 MeV approximately T approximately 2 GeV, but must flatten considerably at lower energies. From the measured electron charge composition, it is concluded that the majority of cosmic-ray electrons with energies above approximately 10 MeV originate in primary sources.

Cummings, A. C.↗

NASA NTRS1973

Possible interaction of interstellar particles with the solar and terrestrial environment

The possibility for detection of interstellar particles in the earth's environment is considered on the basis of the passage of the solar system through the interstellar medium. Among the forces which inhibit interstellar particle penetration, the deflection by the solar magnetic field and the repulsive force due to the radiation from the sun are by far the most important.

Greenberg, J. M.↗