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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

The Viking mission to Mars.

In 1975 the National Aeronautics and Space Administration will launch two unmanned scientific payloads to make soft landings on Mars in 1976. They will be placed in orbit around the planet to perform a reconnaissance before landing. The spacecraft will be separated into an orbiter, which is sent to the surface. During the entry into the Martian atmosphere, Viking will make measurements of the composition and atmospheric structure. After landing, two cameras will be used to visually characterize the site. A device will be deployed to obtain a sample of the Mars surface, which will be returned to the lander for biological tests and for chemical analysis. The atmosphere at the surface will be chemically analyzed as well as the wind velocity, the humidity, and changes in temperature and pressure.

Soffen, G. A.↗
NASA NTRS1974

Titan atmosphere models, 1973

The composition and structure of the atmosphere of Titan, based on theory and on spectroscopic and infrared data, is reviewed for the development of numerical engineering models. Light, nominal, and heavy atmospheres are described and tabulated, and their profiles of radius, temperature, pressure, and density are illustrated. Corresponding descriptions of atmospheric dynamics, condensates and surfaces are outlined.

Divine, N.↗
NASA NTRS1976

Composition and structure of the Martian atmosphere - Preliminary results from Viking 1

Results from the aeroshell-mounted neutral mass spectrometer on Viking 1 indicate that the upper atmosphere of Mars is composed mainly of CO2 with trace quantities of N2, Ar, O, O2, and CO. The mixing ratios by volume relative to CO2 for N2, Ar, and O2 are about 0.06, 0.015, and 0.003, respectively, at an altitude near 135 kilometers. Molecular oxygen is a major component of the ionosphere according to results from the retarding potential analyzer. The atmosphere between 140 and 200 kilometers has an average temperature of about 180 plus or minus 20 deg K. Atmospheric pressure at the landing site for Viking 1 was 7.3 millibars at an air temperature of 241 deg K. The descent data are consistent with the view that CO2 should be the major constituent of the lower Martian atmosphere.

Nier, A. O.↗
NASA NTRS1977

Orbiter Cloud Photopolarimeter for the Pioneer Venus mission

The Orbiter Cloud Photopolarimeter (OCPP) to be flown aboard the Pioneer Venus Orbiter spacecraft is described. This instrument, while in orbit about the planet Venus, will perform polarimetric and radiometric mapping of the Venus atmosphere in four spectral bands centered in the near ultraviolet, visible, and near infrared regions. Additionally, the instrument is equipped to provide moderate resolution imaging of the time varying cloud patterns in the near ultraviolet. In another mode of operation the instrument is capable of profiling the atmosphere at the limb of the planet to measure the particulate layering. Information resulting from these measurements is intended to provide an understanding of the global cloud dynamics and the atmospheric structure and composition on Venus. The basic operation and functional elements of the instrument are discussed. The optical configuration incorporating a polarization analyzing technique with improved accuracy is described. Long-term and short-term calibration techniques along with expected instrument performance characteristics are summarized.

Russell, E. E.↗
NASA NTRS1982

Radiative transfer and remote sensing

Radiative transfer, the basic theoretical tool for the quantitative interpretation of planetary infrared spectra, is discussed. The function it plays in linking the remotely sensed data to the properties of the atmosphere (composition, thermal structure, dynamics, etc.), is inferred. A brief overview of the remote sensing problem as it pertains to the interpretation of planetary spectra is presented. The presentation is tutorial rather than exhaustive.

Conrath, B. J.↗
NASA NTRS1984

Atmospheres of Uranus and Neptune

Current knowledge of the atmospheric compositions and structures are surveyed. Although the two planets are similar in some ways, they are strikingly different in a number of others. The similarities include mass, size, and effective temperature. There are differences in heat flow, stratospheric thermal structure and composition, and spectral appearance. Presumably these are traceable to some combination of Uranus' unusual obliquity and smaller distance from the sun, but most of the details are obscure.

Hunten, D. M.↗
NASA NTRS1985

The Characterization of Surface Variegation Effects on Remote Sensing

Improvements in remote sensing capabilities hinge very directly upon attaining an understanding of the physical processes contributing to the measurements. In order to devise new measurement strategies and to learn better techniques for processing remotely gathered data, it is necessary to understand and to characterize the complex radiative interactions of the atmosphere-surface system. In particular, it is important to understand the role of atmospheric structure, ground reflectance inhomogeneity and ground bidirectional reflectance type. The goals, then, are to model, analyze, and parameterize the observable effects of three dimensional atmospheric structure and composition and two dimensional variations in ground albedo and bidirectional reflectance. To achieve these goals, a Monte Carlo radiative transfer code is employed to model and analyze the effects of many of the complications which are present in nature.

Pearce, W. A.↗
NASA NTRS1985

Nitric oxide profile from 7 to 32 km

An analysis is given of some results of the LIMS experiment, launched on the Nimbus 7 satellite on October 24, 1978 for the purpose of sounding the middle atmosphere composition and structure. One of the LIMS channels was centered spectrally in the 6 micron region to measure vertical profiles and the global distribution of NO2 mixing ratio. The data reveal that NO2 is highly variable with altitude, latitude, longitude and time. Steep latitudinal gradients are observed in high latitude winter ('the NO2 cliff') when a wave number one pattern exists in the geopotential height field. The daytime gradient under these conditions is less than that for the night. The summer hemisphere column amount is considerably greater (by a factor of about 2) than in the winter hemisphere. The largest mixing ratios occur at 4 mb at night (about 20 ppbv) and 9 mb in the day (about 7 ppbv) and the latitude region of the peak mixing ratio is skewed toward the Southern Hemisphere. The mixing ratio variability is greater at night (by a factor of about 2 to 3) than in the day and there are significant long-term changes revealed by mixing ratio time series analyses on a pressure vs time grid.

Matthews, W. A.↗
NASA NTRS1986

Atmospheres and ionospheres of the outer planets and their satellites

Essential aspects of physical and chemical processes in the atmospheres and ionospheres of the outer planets are examined in an introductory overview of current knowledge, intended both for graduate students of planetary science and for practicing scientists. Chapters are devoted to bulk atmospheric compositions, thermal structures, cloud structures, vertical mixing, photochemistry, the ionospheres, and the satellites. Measurement data are compiled in tables, and extensive graphs and diagrams are provided.

Atreya, Sushil K.↗
NASA NTRS1988

The earth observing system - A mission for lidar remote sensing technology

NASA plans an earth observing system (EOS) to address low earth orbit remote sensing satellite requirements. EOS will incorporate three active remote-sensing instruments employing some form of lidar: (1) the Lidar Atmospheric Sounder and Altimeter (LASA), the Laser Atmospheric Wind Sounder (LAWS), and the Geodynamics Laser Ranging System (GLRS). LASA will deepen understanding of atmospheric composition and structure; LAWS will measure winds using Doppler lidar technology; GLRS will be used to ascertain the position of strategically placed retroreflectors to an accuracy of several cm.

Sokoloski, Martin M.↗
NASA NTRS1988

A Saturn atmospheric probe - A proposed augmentation to the Cassini mission

The Saturn probe augmentation of the Cassini mission is studied with particular attention given to the scientific rationale for such an augmentation and any associated issues of technical feasibility, system requirements, performance penalties, and costs. A minimal science complement probe, which concentrates only on atmospheric composition and structure with a total mass requirement of slightly less than 200 kg, is described as well as a full science complement probe with a total mass requirement of about 240 kg. It is noted that either of these Saturn probe configurations can be added to the currently planned mission within the launch performance limitations of the Titan 34D7/Centaur G(prime) launch vehicle.

Swenson, Byron L.↗
NASA NTRS1988

Future observations of and missions to Mercury

Key scientific objectives of Mercury explorations are discussed, and the methods by which remote observations of Mercury can be carried out from earth and from space are examined. Attention is also given to the scientific rationale and technical concepts for missions to Mercury. It is pointed out that multiple Venus-Mercury encounter trajectories exist which, through successive gravity assists, reduce mission performance requirements to levels deliverable by available systems, such as Titan-Centaur, Atlas-Centaur, and Shuttle/TOS. It is shown that a single launch in July of 1994, using a Titan-Centaur combination, could place a 1477-kg payload into orbit around Meercury. The components of a Mercury-orbiter payload designed to study surface geology and geochemistry, atmospheric composition and structure, the local particle and fields environment, and solid-body rotation dynamics are listed.

Stern, Alan S.↗
NASA NTRS1989

Voyager radio science observations of Neptune and Triton

Voyager 2 undertook radio science investigations of the Neptune and Triton masses and densities, as well as of their atmospheric and ionospheric vertical structures, the atmospheric composition and low-order gravitational harmonics of Neptune, and ring material characteristics. Upon probing the atmosphere of Neptune to a pressure level of about 500,000 Pa, the effects of a methane cloud region and of ammonia absorption below the cloud have become apparent. The tenuous neutral atmosphere of Triton produced distinct signatures in the occultation data; it is inferred that the Triton atmosphere is controlled by water-pressure equilibrium with surface ices.

Tyler, G. L.↗
NASA NTRS1991

An interferometric spectral mapper for the Cassini mission to Saturn and Titan

The research reported resulted in a detailed proposal for the Cassini Mission that addressed fundamental atmospheric structure and composition questions for both Saturn and Titan. Due to the brief time available between the initiation of the research and the proposal date, it was necessary to develop the science goals in close synchronicity with the instrument design. A major goal of the program was to acquire, implement, and test SWIR and MWIR arrays suitable for use with the DIGITAL ARRAY SCANNED INTERFEROMETERS, (DASI's), for the extended goal of developing DASI's for a range of spectral mapping research in solar system exploration. These goals were all reached or exceeded in the course of this work.

Smith, William Hayden↗
NASA NTRS1994

The Abundances of Methane and Ortho/Para Hydrogen in Uranus and Neptune: Implications of New Laboratory 4-0 H(sub 2) Quadrapole Line Parameters

The tropospheric methane molar fraction (f(sub ch4,t)) and the ortho/para hydrogen ratio are derived for Uranus and Neptune based on new determinations of spectroscopic parameters for key hydrogen features as reported by Ferguson et al. (1993, J. Mol. Spec 160, 315-325). For each planet, the relatively weak laboratory linestrengths (approximately 30% and 15% less than the theoretical 4-0 S(0) and S(1) linestrengths, respectively) results, when compared to analyses adopting theoretical values, in a ~30% decrease in the tropospheric methane ratio and a comparable increase in the pressure level of the optically-thick cloudtop marking the bottom of the visible atmosphere (P(sub cld)).

Uranus atmosphere; Neptune atmosphere; abundances ↗
NASA NTRS2013

Classification of Aerosol Retrievals from Spaceborne Polarimetry Using a Multiparameter Algorithm

In this presentation, we demonstrate application of a new aerosol classification algorithm to retrievals from the POLDER-3 polarimter on the PARASOL spacecraft. Motivation and method: Since the development of global aerosol measurements by satellites and AERONET, classification of observed aerosols into several types (e.g., urban-industrial, biomass burning, mineral dust, maritime, and various subtypes or mixtures of these) has proven useful to: understanding aerosol sources, transformations, effects, and feedback mechanisms; improving accuracy of satellite retrievals and quantifying assessments of aerosol radiative impacts on climate.

Atmospheric Processes Clouds & Aerosols↗