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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Study of spin-scan imaging for outer planets missions

The constraints that are imposed on the Outer Planet Missions (OPM) imager design are of critical importance. Imager system modeling analyses define important parameters and systematic means for trade-offs applied to specific Jupiter orbiter missions. Possible image sequence plans for Jupiter missions are discussed in detail. Considered is a series of orbits that allow repeated near encounters with three of the Jovian satellites. The data handling involved in the image processing is discussed, and it is shown that only minimal processing is required for the majority of images for a Jupiter orbiter mission.

Russell, E. E.↗
NASA NTRS1974

Satellites and magnetospheres of the outer planets

The known properties of the satellites of the outer planets are reviewed and an attempt is made to provide explanations for some of the more striking features in terms of interaction with the planetary magnetospheres. It is pointed out that all the larger satellites, with the exception of Iapetus, are likely to lie within the magnetospheres of their respective planets at all times. Attention is given to the possibility that the satellites and other solid bodies situated within the planetary magnetospheres become charged to rather large electrical potentials. Satellite brightness variations are considered together with the atmospheres of the satellites.

Mendis, D. A.↗
NASA NTRS1988

Infrared observations of outer planet satellites

This task supports IR observations of the outer planet satellites. These data provide vital information about the thermophysical properties of satellite surfaces, including internal heat sources for Io. Observations include both broad and narrow band measurementsin the 2 to 20 micrometer spectral range. The program in the last year has aimed at obtaining lonitude coverage on Io to establish stability of hot spot patterns previously reported. Several runs produced the most complete data set for an apparition since the start of the program. Unfortunately, bad weather limited coverage of key longitude ranges containing the largest known hot spot Loki. Among the preliminary results is the observation of an outburst in Io's thermal flux that was measured at 4.8, 8.7 and 20 micrometer. Analysis of the data has given the best evidence to date of silicate volcanism on Io; this is one of the most significant pieces of the puzzle as to the relative roles of silicate and sulfur volcanism on Io. Researchers are collaborating with J. Goguen (NRC RRA to finish reduction of mutual event data, which have already improved ephermeris information for the satellites. The data appear to place significant limits on the characteristics of any leading side hot spots.

Johnson, T. V.↗
NASA NTRS1990

An approximation to the outer planet ephemeris errors in JPL's DE 200

The outer planet positions of JPL's recent planetary ephemeris, DE 202, have begun to show significant differences from DE 200, the basic ephemeris of the major national almanacs. The differences DE 202 - DE 200 are plotted and are assumed to approximate the errors of DE 200. For Jupiter, the difference in right ascension varies over the planet's 12 yr period between -0.1 and -0.2 arcsec throughout the century; for Saturn, the right ascension also varies over the 30 yr period, but in addition, shows a drift which reaches -0.25 arcsec at present; for Uranus, the difference is small through the first half of the century, but now has reached -0.4 arcsec; for Neptune, the error was +0.6 arcsec at 1900 and is near -1.0 arcsec by the year 2000; the error for Pluto exceeds +2.0 arcsec by the end of the century and is rapidly increasing. The declination errors are generally periodic and smaller than the right ascensions.

Standish, E. M., Jr.↗
NASA NTRS1991

The magnetospheres of the outer planets

Research on the magnetospheres of all of the outer planets including Jupiter, Uranus, Neptune, and Pluto is reviewed for the 1987-1990 time period. Particular attention is given to magnetospheric structure, plasma transport, Jovian aurora, Io and the plasma torus, Titan and its magnetospheric interactions, rings and dusty plasmas, magnetospheric convection, and satellite interactions.

Mcnutt, Ralph L., Jr.↗
NASA NTRS1992

Variability in the outer planet aurorae

Multiwavelength observations of the aurorae of the outer planets are reviewed emphasizing the findings on physical processes derived from specific wavelengths. The review examines features of the auroral zones such as ionospheric currents, atmospheric heating, and compositional changes in the aurorae of Jupiter, Saturn, Uranus, Neptune, and the earth for comparison. Jupiter's multiwavelength aurora receives special attention since recent observations shed light on the distribution of the UV auroral ovals, the spectroscopy of the UV auroral emissions, auroral dynamics and ion upwelling, and IR emission from auroral latitudes. The observational data on Jupiter facilitate the modeling of variability and detailed thermospheric and magnetospheric processes. Saturn can be studied by extending findings fron Jupiter's aurora, and deficiencies are found in the observational datasets for Neptune and Uranus.

Clarke, John T.↗
NASA NTRS1993

Origins of outer-planet satellites

Aspects of satellite origin and evolution which bear on the formation of the solar system are addressed, with emphasis on the chemical evidence contained in satellites concerning the modification of the interstellar material which went to form the solar system. New results on the tidal evolution of outer-planet satellite systems are presented. The gross physical and chemical properties of the satellite systems of the outer planets are outlined. Models for regular satellite formation are reviewed. Attention is given to the evolution of the satellites, with emphasis on tidal evolution, including a discussion of the dynamical origin of Triton. The volatile budgets of Titan, Triton, and Pluto/Charon are discussed, and models are presented for the origin of these budgets which tie them to the larger set of processes associated with solar system formation.

Lunine, Jonathan I.↗
NASA NTRS2015

Study of Power Options for Jupiter and Outer Planet Missions

Power for missions to Jupiter and beyond presents a challenging goal for photovoltaic power systems, but NASA missions including Juno and the upcoming Europa Clipper mission have shown that it is possible to operate solar arrays at Jupiter. This work analyzes photovoltaic technologies for use in Jupiter and outer planet missions, including both conventional arrays, as well as analyzing the advantages of advanced solar cells, concentrator arrays, and thin film technologies. Index Terms - space exploration, spacecraft solar arrays, solar electric propulsion, photovoltaic cells, concentrator, Fresnel lens, Jupiter missions, outer planets.

jupiter↗
NASA NTRS2014

Solar System Exploration Augmented by Lunar and Outer Planet Resource Utilization: Historical Perspectives and Future Possibilities

Establishing a lunar presence and creating an industrial capability on the Moon may lead to important new discoveries for all of human kind. Historical studies of lunar exploration, in-situ resource utilization (ISRU) and industrialization all point to the vast resources on the Moon and its links to future human and robotic exploration. In the historical work, a broad range of technological innovations are described and analyzed. These studies depict program planning for future human missions throughout the solar system, lunar launched nuclear rockets, and future human settlements on the Moon, respectively. Updated analyses based on the visions presented are presented. While advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal propulsion, nuclear surface power, as well as advanced chemical propulsion can significantly enhance these scenarios. Robotic and human outer planet exploration options are described in many detailed and extensive studies. Nuclear propulsion options for fast trips to the outer planets are discussed. To refuel such vehicles, atmospheric mining in the outer solar system has also been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as helium 3 (3He) and hydrogen (H2) can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and H2 (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses have investigated resource capturing aspects of atmospheric mining in the outer solar system. These analyses included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of additional exploration and exploitation vehicles exists.

Palaszewski, Bryan↗
NASA NTRS2014

Solar System Exploration Augmented by Lunar and Outer Planet Resource Utilization: Historical Perspectives and Future Possibilities

Establishing a lunar presence and creating an industrial capability on the Moon may lead to important new discoveries for all of human kind. Historical studies of lunar exploration, in-situ resource utilization (ISRU) and industrialization all point to the vast resources on the Moon and its links to future human and robotic exploration. In the historical work, a broad range of technological innovations are described and analyzed. These studies depict program planning for future human missions throughout the solar system, lunar launched nuclear rockets, and future human settlements on the Moon, respectively. Updated analyses based on the visions presented are presented. While advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal propulsion, nuclear surface power, as well as advanced chemical propulsion can significantly enhance these scenarios. Robotic and human outer planet exploration options are described in many detailed and extensive studies. Nuclear propulsion options for fast trips to the outer planets are discussed. To refuel such vehicles, atmospheric mining in the outer solar system has also been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses have investigated resource capturing aspects of atmospheric mining in the outer solar system. These analyses included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of additional exploration and exploitation vehicles exists.

Palaszewski, Bryan↗
NASA NTRS1977

Formation of the outer planets and satellites

A mechanism for the formation of the outer planets is proposed, the basis of which is the idea that the giant planets contain an excess of chemically condensable materials over solar composition. Planetary cores were formed by the clumping together of chemically condensed bodies forming a thin disk in the solar nebula. Gas surrounding a core becomes unstable against collapse onto the core. In the case of Jupiter and Saturn, much of the collapsing gas goes into orbit about the formed planet, forming a relatively thin circumplanetary disks with differential rotation in the prograde sense. For Uranus and Neptune, the dynamical collapse mechanism is unlikely. A disk of gas around Uranus may have been formed during a collision of the protoplanet with a large body. The circumplanetary disks then form the basis for formation of satellite systems, in which the Goldreich-Ward instability mechanism plays a role.

Cameron, A. G. W.↗
NASA NTRS1985

Energy conversion processes in the outer planets

Energy conversion processes which are potentially important in the outer planets at pressures greater than obut 0.1 bar are reviewed. Generation of buoyancy contrasts by condensation of various constituents is discussed with emphasis on the possible significance of phase changes in substances such as Si and Mg compounds at deep levels. It is demonstrated that, in the absence of nonequilibrium thermodynamic processes, strong kinetic energy generation must accompany the transport of heat out of the high temperature planetary interiors. The possibly dominant role of lagged parahydrogen conversion in the convective transport of heat at levels where T is less than 300 K is discussed. Measurements which may ultimately contribute to a better understanding of energy conversion processes are summarized.

Gierasch, P. J.↗
NASA NTRS2008

Overview of 2008 Outer Planet Flagship Studies

This slide presentation reviews the process involved in the Phase-2 studies for the next Outer Planets Flagship (OPF). These studies will be a cooperative effort with ESA and JAXA in partnership with NASA. The annoucement of oppurtunity (AO) for the science instruments and the launch approval/planetary protection processes are reviewed. There is also discussion about capturing relevant lessons from the Cassini team, supporting international collaboration, and support for science definition teams. Some mission specific tasks are also reviewed, for the three missions being proposed: (1) Europa Explorer, (2) Jupiter System Observer and (3) Titan Explorer. A timeline for the studies is also included.

outer planets↗
NASA NTRS1992

Dynamics of the atmospheres of the outer planets

Current knowledge about dynamics and the thermal structure of the outer planets is reviewed with the aim of identifying important measurements which should be made in the post-Voyager era. The existence of jets and cloud bands is the puzzle that underlies all others. The discussion focuses on the particular case of Jupiter because the documentation is the most complete. It is argued that the gross dynamical parameters of the outer planetary atmospheres are the keys to their behaviors, rather than the particular specifics of radiative forcing, cloud distributions, or thermodynamic transformations. Voyager data has shown that the jet systems decay with height in the region above the visible clouds. Therefore, the highest priority must be given to establishing dynamical parameters that characterize levels within and beneath the clouds. These require the determination of the deep structure of the jets, of the density stratification, and of the horizontal density contrasts. The deep regions are not easily accessible and these measurements present challenging opportunities. Indirect inferences about the controlling processes may sometimes be possible by observing waves and other activity in the more easily accessible stratosphere.

Gierasch, Peter J.↗