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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.

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At least 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

Gravity Poppers: Hopping Probes for the Internal Mapping of Small Solar System Bodies

This paper presents the results of NIAC Phase I study into the feasibility of a novel mission architecture for highresolution gravity science on small Solar System bodies. The “Gravity Poppers” mission concept (see Fig. 1) consists of a swarm of small, minimalistic probes that are deployed from a mother spacecraft to the surface of a small body and which periodically and randomly hop around the surface. By tracking the ballistic sub-orbital trajectories of this hopping swarm, a very high resolution gravity field can be measured, which can then be used to answer a number of scientific questions of interest regarding the interior mass distribution of the body. This paper describes the three core focus areas of our study to demonstrate concept feasibility: (1) the design of hopping probes to be small, simple, robust, and “visible” to a distant spacecraft, (2) the tracking strategy for detecting and estimating the trajectories of a large number of ballistic probes, and (3) the algorithmic framework by which such measurements can be used to estimate the body’s gravity field. Our results suggest the ability to estimate the gravity field of a 500m asteroid beyond degree-and-order 40 through days to weeks of optical tracking of several LED-strobing probes, with a mass of only 200 g each. Collectively, this study demonstrates that the high-resolution gravity mapping of small body interiors is technically possible, economically feasible, and would enable a compelling set of science objectives aligned with NASA’s goals in planetary science, planetary defense, and future interests in resource prospecting.

McMahon, Jay↗
NASA NTRS1975

Measuring the magnetic fields of Jupiter and the outer solar system

The vector helium magnetometer, one of the Pioneer-Jupiter experiments, has measured the magnetic field of Jupiter and the interplanetary magnetic field in the outer solar system. The comprehensive scientific objectives of the investigations are explained and are then translated into the major instrument requirements. The principles of operation of the magnetometer, which involve the optical pumping of metastable helium, are discussed and the Pioneer instrument is described. The in-flight performance of the magnetometer is discussed and principal scientific results obtained thus far by the Pioneer investigation are summarized.

Smith, E. J.↗
NASA NTRS2016

James Webb Space Telescope Observations of Stellar Occultations by Solar System Bodies and Rings

In this paper, we investigate the opportunities provided by the James Webb Space Telescope (JWST) for significant scientific advances in the study of Solar System bodies and rings using stellar occultations. The strengths and weaknesses of the stellar occultation technique are evaluated in light of JWST's unique capabilities. We identify several possible JWST occultation events by minor bodies and rings and evaluate their potential scientific value. These predictions depend critically on accurate a priori knowledge of the orbit of JWST near the Sun–Earth Lagrange point 2 (L2). We also explore the possibility of serendipitous stellar occultations by very small minor bodies as a byproduct of other JWST observing programs. Finally, to optimize the potential scientific return of stellar occultation observations, we identify several characteristics of JWST's orbit and instrumentation that should be taken into account during JWST's development.

Santos-Sanz, P.↗
NASA NTRS2017

Spacecraft/Rover Hybrids for the Exploration of Small Solar System Bodies: Final Report: NASA NIAC - Phase II Study

This study investigated a mission architecture that allows the systematic and affordable in-situ exploration of small solar system bodies, such as asteroids, comets, and Martian moons (Figure 1). The architecture relies on the novel concept of spacecraft/rover hybrids,which are surface mobility platforms capable of achieving large surface coverage (by attitude controlled hops, akin to spacecraft flight), fine mobility (by tumbling), and coarse instrument pointing (by changing orientation relative to the ground) in the low-gravity environments(micro-g to milli-g) of small bodies. The actuation of the hybrids relies on spinning three internal flywheels. Using a combination of torques, the three flywheel motors can produce a reaction torque in any orientation without additional moving parts. This mobility concept allows all subsystems to be packaged in one sealed enclosure and enables the platforms to be minimalistic. The hybrids would be deployed from a mother spacecraft, which would act as a communication relay to Earth and would aid the in-situ assets with tasks such as localization and navigation (Figure 1). The hybrids are expected to be more capable and affordable than wheeled or legged rovers, due to their multiple modes of mobility (both hopping and tumbling), and have simpler environmental sealing and thermal management (since all components are sealed in one enclosure, assuming non-deployable science instruments). In summary, this NIAC Phase II study has significantly increased the TRL (Technology Readiness Level) of the mobility and autonomy subsystems of spacecraft/rover hybrids, and characterized system engineering aspects in the context of a reference mission to Phobos. Future studies should focus on improving the robustness of the autonomy module and further refine system engineering aspects, in view of opportunities for technology infusion.

mobility platforms↗
NASA NTRS1978

The radial variation of corotating energetic particle streams in the inner and outer solar system

Spacecraft observations of 0.9 to 2.2 MeV protons are used to evaluate the radial gradient of long-lived corotating energetic particle streams for several time periods from mid-1973 to mid-1976. New evidence is presented for a positive gradient between 0.3 and some 3-4 AU and a negative one beyond some 3-5 AU. The relation between the corotating events in the inner solar system and the accompanying interplanetary magnetic field and solar wind is examined. It is shown, independently of possible secondary latitudinal effects, that between 0.3 and 1 AU, in a region where gradients up to 300%/AU exist, the particle stream is propagating inside a fast solar wind stream in a region adjacent to low- and high-speed stream interactions.

Van Hollebeke, M. A. I.↗
NASA NTRS2018

Probing the Composition of Primitive Solar System Materials with a Compact Laser Mass Spectrometer

To contribute to and complement our understanding of the processes governing the formation,distribution, and evolution of primitive materials throughout the solar system, it will be critical toform connections between broad remote sensing spectroscopic surveys, laboratorymeasurements of analogs and samples delivered to Earth, and in situ measurements of thesurface composition on future primitive body missions. Recently, a laboratory prototypeemploying resonance two-step laser mass spectrometry [Getty et al., 2012] has been coupledto a cryogenic sample stage to enable measurements of analog samples that are relevant tothese fundamental questions. Analyses of mineral-aromatic mixtures and meteorite powderswill be presented. Our goals are twofold: (1) to conduct laboratory studies on solar systemanalog, meteoritic, and potentially returned samples to elucidate composition, and (2) toprovide a compact but capable analytical instrument for discovery-driven in situ interrogationof surface chemistry on a future mission, such as to a Trojan asteroid, comet, or icy moon.

Getty, Stephanie A.↗
NASA NTRS1983

Internationally supported data acquisition for solar system exploration in the 1990's

Procedures that could be followed for cooperative agreements between countries with large ground station antennas to help provide mission telemetry support for increasing solar system exploration are outlined. It is noted that mission cost reductions, and thereby greater chances that missions will be approved, are offered by the opportunity to make planetary probes multinational efforts. The Canberra station is a suitable site for the Japanese Planet A Halley's comet intercept probe. The French have requested U.S. cooperation in developing VLBI stations in the L-band to receive signals from the Venus balloons and landers being sent as part of a joint French-Soviet mission to Venus and Halley's comet. The construction of the stations would extend the capabilities already present with NASA's deep space network, particularly for tracking the Voyager visits to Uranus and Neptune.

Reid, M. S.↗
NASA NTRS1991

Laboratory and observational study of the interrelation of the carbonaceous component of interstellar dust and solar system materials

By studying the chemical and isotopic composition of interstellar ice and dust, one gains insight into the composition and chemical evolution of the solid bodies in the solar nebula and the nature of the material subsequently brought into the inner part of the solar system by comets and meteorites. It is now possible to spectroscopically probe the composition of interstellar ice and dust in the mid-infrared, the spectral range which is most diagnostic of fundamental molecular vibrations. We can compare these spectra of various astronomical objects (including the diffuse and dense interstellar medium, comets, and the icy outer planets and their satellites) with the spectra of analogs we produce in the laboratory under conditions which mimic those in these different objects. In this way one can determine the composition and abundances of the major constituents of the various ices and place general constraints on the types of organics coating the grains in the diffuse interstellar medium. In particular we have shown the ices in the dense clouds contain H2O, CH3OH, CO, perhaps some NH3 and H2CO, we well as nitriles and ketones or esters. Furthermore, by studying the photochemistry of these ice analogs in the laboratory, one gains insight into the chemistry which takes place in interstellar/precometary ices. Chemical and spectroscopic studies of photolyzed analogs (including deuterated species) are now underway. The results of some of these studies will be presented and implications for the evolution of the biogenic elements in interstellar dust and comets will be discussed.

Allamandola, L. J.↗
NASA NTRS1991

An inertial fusion propulsion scheme for solar system exploration

The paper analyzes a novel fusion scheme that combines the favorable aspects of both inertial and magnetic confinement approaches as a propulsion device for potential application in solar system exploration. An appropriate set of equations for the plasma dynamics and the magnetic nozzle is used to assess the system's propulsive capability by applying the results to a round trip mission to Mars. It is found that such a device would allow a massive vehicle to make the journey in less than five months. It is shown that catalyzed deuterium-deuterium fuel results in a somewhat poorer propulsion performance than deuterium-tritium though at a significantly lower neutron production. The velocity increment generated by this system and the corresponding trip time are in excellent agreement with the predictions of Irving and Blum (1959).

Kammash, Terry↗
NASA NTRS2024

Distribution of -92 Nb in the Early Solar System

Constraining the initial abundances of short-lived radionuclides in planetary materials helps determine the spatial and temporal distribution of interstellar material added during the initial stages of Solar System formation.

short-lived chronometer↗
NASA NTRS1980

A model for nitrogen isotopic variations in the lunar regolith - Possible solar system contributions from a nearby planetary nebula

To account for the observed secular increase of the N-15/N-14 ratio in lunar samples, a model is developed which envisions an encounter between a planetary nebula and the solar system during the first few hundred million years of its history. The principal effects of the encounter for the sun's outer convective zone, and hence solar wind, due to accretion of planetary nebula material with its distinct nucleosynthetic history are delineated. Associated material contributions to planets and meteorite parent bodies are considered and contraints relevant to this possibility are discussed.

Ray, J.↗
NASA NTRS1985

Theoretical interpretation of the observed interplanetary magnetic field radial variation in the outer solar system

Observations of the azimuthal component of the IMF are evaluated through the use of an MHD model which shows the effect of magnetic flux tubes opening in the outer solar system. It is demonstrated that the inferred meridional transport of magnetic flux is consistent with predictions by the MHD model. The computed azimuthal and radial magnetic flux deficits are almost identical to the observations. It is suggested that the simplest interpretation of the observations is that meridional flows are created by a direct body force on the plasma. This is consistent with the analytic model of Nerney and Suess (1975), in which such flux deficits in the IMF arise naturally from the meridional gradient in the spiralling field.

Suess, S. T.↗
NASA NTRS1991

Goldstone solar system radar

This task provides for the planning, experiment design, and coordination of the data acquisition and engineering activities in support of all Goldstone planetary radar astronomy. Activities related to up-grades of the receiver systems, transmitter systems, and data processing support systems are currently intense. Also, the hardware and software maintenance of the data processing facility used by many of the Goldstone Solar System Radar investigators are covered.

Jurgens, Raymond F.↗
NASA NTRS2001

Continued Analysis of EUVE Solar System Observations

This is the final report for this project. We proposed to continue our work on extracting important results from the EUVE (Extreme UltraViolet Explorer) archive of lunar and jovian system observations. In particular, we planned to: (1) produce several monochromatic images of the Moon at the wavelengths of the brightest solar EUV emission lines; (2) search for evidence of soft X-ray emissions from the Moon and/or X-ray fluorescence at specific EUV wavelengths; (3) search for localized EUV and soft X-ray emissions associated with each of the Galilean satellites; (4) search for correlations between localized Io Plasma Torus (IPT) brightness and volcanic activity on Io; (5) search for soft X-ray emissions from Jupiter; and (6) determine the long term variability of He 58.4 nm emissions from Jupiter, and relate these to solar variability. However, the ADP review panel suggested that the work concentrate on the Jupiter/IPT observations, and provided half the requested funding. Thus we have performed no work on the first two tasks, and instead concentrated on the last three. In addition we used funds from this project to support reduction and analysis of EUVE observations of Venus. While this was not part of the original statement of work, it is entirely in keeping with extracting important results from EUVE solar system observations.

Gladstone, G. Randall↗
DOE OSTI2024

Anisotropic neutron star crust, solar system mountains, and gravitational waves

"Mountains" or non-axisymmetric deformations of rotating neutron stars (NS) efficiently radiate gravitational waves (GW). We consider analogies between NS mountains and surface features of solar system bodies. Both NS and moons such as Europa or Enceladus have thin crusts over deep oceans while Mercury has a thin crust over a large metallic core. Thin sheets may wrinkle in universal ways. Europa has linear features, Enceladus has "Tiger" stripes, and Mercury has lobate scarps. NS may have analogous features. The innermost inner core of the Earth is anisotropic with a shear modulus that depends on direction. If NS crust material is also anisotropic this will produce an ellipticity, when the crust is stressed, that grows with spin frequency. This yields a braking index (log derivative of spin down rate assuming only GW spin down) very different from n=5 and could explain the maximum spin observed for neutron stars and a possible minimum ellipticity of millisecond pulsars.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Protracted core formation and impact disruptions shaped the earliest outer Solar System planetesimals

The distinct compositions of metallic cores from noncarbonaceous (NC) and carbonaceous (CC) iron meteorite parent bodies (IMPBs) reflect differences in accretion and differentiation histories of earliest inner and outer Solar System planetesimals. Compared to NC IMPBs, CC IMPBs have smaller, sulfur (S)–poor, highly siderophile element (HSE)–enriched cores and younger core formation ages. However, the origins of these differences remain debated. Using equilibrium partitioning models between the S-poor solid and the S-rich liquid metal, we argue that HSE enrichment in IID, IIF, IIIF, and IVB cores resulted from a multistage evolutionary sequence: (i) segregation of S-rich, HSE-depleted protocores during initial planetesimal heating; (ii) collisional disruption before S-poor metal segregation; (iii) reaccretion of mantle fragments into daughter planetesimals; and (iv) further 26 Al-driven heating producing HSE-enriched, S-poor cores. We suggest that iron meteorites from these CC IMPBs originate from such second-generation cores. Accounting for “missing” S-rich protocores helps reconcile several NC-CC IMPB differences and highlights the role of early collisional processing in shaping planetesimal chemical evolution.

Geosciences↗