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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

A Mars sample return mission using a rover for sample acquisition

Mission and vehicle concepts are discussed for obtaining surface and subsurface samples of Mars, acquired by a roving vehicle, and returning those samples to earth for detailed analyses in scientific laboratories. Mission options that were traded off in order to arrive at a baseline mission considered most worthy of further study comprised the following: (1) direct entry vs entry out of Mars orbit; (2) direct return from the Mars surface vs rendezvous in Mars orbit and return to earth from there; and (3) propulsive orbit injection and aeroballistic entry (similar to Viking) vs aerocapture into Mars orbit and aeromaneuvering entry. After a comparison of relative merits - based primarily on mass and cost estimates and secondarily on configurational constraints - a baseline mission was selected: out-of-orbit entry, return after Mars orbit rendezvous, and aerocapture/aeromaneuvering. Trajectory design is based on the 1996 launch opportunity. Launch mass requirements for eight mission options, a mission and vehicle description for the baseline mission, and the outline of a mission sequence of events are presented.

De Vries, J. P.↗
NASA NTRS1977

Chemical and optical properties at the Apollo 15 and 16 sites

The bulk chemical composition, the surface chemical concentration of four major elements, and the optical albedo were determined for six core samples, for two sites and from four different depths below the lunar surface, and also for surface soil samples from the vicinity of the sites of the cores. The chemical composition of the core samples was found to be related to that of the surface samples from the same sites, and the correlation of the albedo with the surface iron plus titanium content that has previously been demonstrated for the surface samples was also verified for the core samples. A soil layer near the bottom of the Apollo 15 deep drill core was found to be unusual in two respects: the grain surface and the bulk chemical compositions were found to be more similar than is usual, and the albedo was exceptionally high, though still only 0.6 of the albedo of crushed rock of similar composition. The mechanism of darkening of lunar soil is discussed in the light of these observations.

Gold, T.↗
NASA NTRS1991

An investigation of the degradation of Fluorinated Ethylene Propylene (FEP) copolymer thermal blanketing materials aboard LDEF in the laboratory

Samples of fluorinated ethylene propylene copolymer thermal blanketing material, recovered from the Long Duration Exposure Facility (LDEF), were investigated to determine the nature and the extent of degradation due to exposure to the low-Earth-orbit environment. Samples recovered from the ram-facing direction of LDEF, which received vacuum-ultraviolet (VUV) radiation and atomic-oxygen impingement, and samples from the trailing edge, which received almost exclusively VUV exposure, were investigated by scanning electron microscopy and atomic force microscopy. The most significant result of this investigation was found on samples that received only VUV exposure. These samples possessed a hard, embrittled surface layer that was absent from the atomic-oxygen exposed sample and from unexposed control samples. This surface layer is believed to be responsible for the 'synergistic' effect between VUV and atomic oxygen. Overall, the investigation revealed dramatically different morphologies for the two samples. The sample receiving both atomic-oxygen and VUV exposure was deeply eroded and had a characteristic 'rolling' surface morphology, while the sample that received only VUV exposure showed mild erosion and a surface morphology characterized by sharp high-frequency peaks. The morphologies observed in the LDEF samples, including the embrittled surface layer, were successfully duplicated in the laboratory.

Stiegman, A. E.↗
NASA NTRS1989

The effect of hydrogen on the deformation behavior of a single crystal nickel-base superalloy

The effect of hydrogen on the tensile deformation behavior of PWA 1480 is presented. Tensile tests were interrupted at different plastic strain levels to observe the development of the dislocation structure. Transmission electron microscopy (TEM) foils were cut perpendicular to the tensile axis to allow the deformation of both phases to be simultaneously observed as well as parallel to zone axes (III) to show the superdislocations on their slip planes. Similar to other nickel-base superalloys, hydrogen was detrimental to the room temperature tensile properties of PWA 1480. There was little effect on strength, however the material was severely embrittled. Even without hydrogen, the elongation-to-failure was only approximately 3 percent. The tensile fracture surface was made up primarily of ductile voids with regions of cleavage fracture. These cleavage facets are the eutectic (gamma') in the microstructure. It was shown by quantitative fractography that hydrogen embrittles the eutectic (gamma') and causes the crack path to seek out and fracture through the eutectic (gamma'). There was two to three times the amount of cleavage on the fracture surface of the hydrogen-charged samples than on the surface of the uncharged samples. The effect of hydrogen can also be seen in the dislocation structure. There is a marked tendency for dislocation trapping in the gamma matrix with and without hydrogen at all plastic strain levels. Without hydrogen there is a high dislocation density in the gamma matrix leading to strain exhaustion in this region and failure through the matrix. The dislocation structure at failure with hydrogen is slightly different. The TEM foils cut parallel to zone axes (III) showed dislocations wrapping around gamma precipitates. Zone axes (001) foils show that there is a lower dislocation density in the gamma matrix which can be linked to the effects of hydrogen on the fracture behavior. The primary activity in the gamma precipitates is in the form of superlattice intrinsic stacking faults (SISFs). These faults have also been reported in other ordered alloys and superalloys.

Walston, W. S.↗
NASA NTRS2009

Lunar Samples: Apollo Collection Tools, Curation Handling, Surveyor III and Soviet Luna Samples

The 6 Apollo missions that landed on the lunar surface returned 2196 samples comprised of 382 kg. The 58 samples weighing 21.5 kg collected on Apollo 11 expanded to 741 samples weighing 110.5 kg by the time of Apollo 17. The main goal on Apollo 11 was to obtain some material and return it safely to Earth. As we gained experience, the sampling tools and a more specific sampling strategy evolved. A summary of the sample types returned is shown in Table 1. By year 1989, some statistics on allocation by sample type were compiled [2]. The "scientific interest index" is based on the assumption that the more allocations per gram of sample, the higher the scientific interest. It is basically a reflection of the amount of diversity within a given sample type. Samples were also set aside for biohazard testing. The samples set aside and used for biohazard testing were represen-tative, as opposed to diverse. They tended to be larger and be comprised of less scientifically valuable mate-rial, such as dust and debris in the bottom of sample containers.

Allton, J.H.↗
NASA NTRS2013

The Sample Handling System for the Mars Icebreaker Life Mission: from Dirt to Data

The Mars icebreaker life mission will search for subsurface life on mars. It consists of three payload elements: a drill to retrieve soil samples from approx. 1 meter below the surface, a robotic sample handling system to deliver the sample from the drill to the instruments, and the instruments themselves. This paper will discuss the robotic sample handling system.

Martian Arctic↗
NASA NTRS1981

A remark on the theory of measuring thermal diffusivity by the modified Angstrom's method

A theory of the measurement of the thermal diffusivity of a sample by the modified Angstrom method is developed for the case in which radiative heat loss from the end surface of the sample is not negligible, and applied to measurements performed on lunar samples. Formulas allowing sample thermal diffusivity to be determined from the amplitude decay and phase lag of a temperature wave traveling through the sample are derived for a flat disk sample for which only heat loss from the end surface is important, and a sample of finite diameter and length for which heat loss through the end and side surfaces must be considered. It is noted that in the case of a flat disk, measurements at a single angular frequency of the temperature wave are sufficient, while the sample of finite diameter and length requires measurements at two discrete angular frequencies. Comparison of the values of the thermal diffusivities of two lunar samples of dimensions approximately 1 x 1 x 2 cm derived by the present methods and by the Angstrom theory for a finite bar reveals them to differ by not more than 5%, and indicates that more refined data are required as the measurement theory becomes more complicated.

Horai, K.-I.↗
NASA NTRS2012

Method and system for near-field spectroscopy using targeted deposition of nanoparticles

There is provided in one embodiment of the invention a method for analyzing a sample material using surface enhanced spectroscopy. The method comprises the steps of imaging the sample material with an atomic force microscope (AFM) to select an area of interest for analysis, depositing nanoparticles onto the area of interest with an AFM tip, illuminating the deposited nanoparticles with a spectrometer excitation beam, and disengaging the AFM tip and acquiring a localized surface enhanced spectrum. The method may further comprise the step of using the AFM tip to modulate the spectrometer excitation beam above the deposited nanoparticles to obtain improved sensitivity data and higher spatial resolution data from the sample material. The invention further comprises in one embodiment a system for analyzing a sample material using surface enhanced spectroscopy.

Anderson, Mark S.↗
NASA NTRS1993

Chemical analyses of provided samples

A batch of four samples were received and chemical analysis was performed of the surface and near surface regions of the samples by the surface analysis by laser ionization (SALI) method. The samples included four one-inch diameter optics labeled windows no. PR14 and PR17 and MgF2 mirrors 9-93 PPPC exp. and control DMES 26-92. The analyses emphasized surface contamination or modification. In these studies, pulsed desorption by 355 nm laser light and single-photon ionization (SPI) above the sample by coherent 118 nm radiation (at approximately 5 x 10(exp 5) W/cm(sup 2)) were used, emphasizing organic analysis. For the two windows with an apparent yellowish contaminant film, higher desorption laser power was needed to provide substantial signals, indicating a less volatile contamination than for the two mirrors. Window PR14 and the 9-93 mirror showed more hydrocarbon components than the other two samples. The mass spectra, which show considerable complexity, are discussed in terms of various potential chemical assignments.

Becker, Christopher H.↗
NASA NTRS1994

Spectral emissivity measurements of land-surface materials and related radiative transfer simulations

Spectral radiance measurements have been made in the laboratory and in the field for deriving spectral emissivities of some land cover samples with a spectroradiometer and an auxiliary radiation source in the wavelength range 2.5-14.5 micrometers. A easy and quick four-step method (four steps to measure the sample and a diffuse reflecting plate surface under sunshine and shadowing conditions, respectively) has been used for simultaneous determination of surface temperature and emissivity. We emphasized in-situ measurements in combination with radiative transfer simulations, and an error analysis for basic assumptions in deriving spectral emissivity of land-surface samples from thermal infrared measurements.

Wan, Z.↗
NASA NTRSDate not supplied

Venus Sample Return Using In-situ Propellant

This project will pioneer a new approach to return a sample from the surface of Venus. At 450°C and 92 bar pressure, the Venus surface is the most hostile environment in the solar system. This project merges an innovative carbon monoxide rocket concept using propellant made from the Venus atmosphere with innovations in high-temperature technology and solar aircraft. We turn an ambitious mission into a reality. The mission will return a sample from the scorching surface of Venus, using a novel multi-step approach incorporating new technology. The high-temperature solar aircraft collects the sample from the surface and carries it above the main cloud deck to a balloon platform with a launch vehicle & propellant manufacturing plant. The carbon monoxide/oxygen monopropellant is manufactured from the Venus atmosphere.

Venus↗
NASA NTRS2010

Examining the Uppermost Surface of the Lunar Regolith

This slide presentation reviews the examination of the uppermost surface of the lunar regolith. It shows the mechanism (i.e. a Clam Shell Sampling Device) that was used to retrieve samples of the surface of the lunar soil. Samples were obtained from the devices, and they were examined in the scanning electron microscope (SEM). Using a lunar simulant, JSC-1a, test were run to ascertain if the sample from the clam shell device were biased due to the collection. The results of the test were that all the fine grains analyzed to the limit of the capabilities were found to be lunar in composition, though non-lunar contaminants may exist in the submicron population. Further work is required, though the initial study shows that the uppermost surface is enriched in fine (< 2 micron grains) compared to the bulk soil.

Noble, Sarah↗
NASA NTRS1974

Study of isotopic composition of helium in the fine fraction of Luna 16 lunar surface material

The content of He isotopes is measured in two samples of the lunar surface material returned by the Luna 16 automatic station. Both samples consist of a fine fraction of lunar surface material and were samples from zone A (sample 3-2k) and from zone V (sample 9-1r). The value of He4/He3 and the concentration of the He isotopes are identical for both samples, within the limits of experimental error.

Boltenkov, B. S.↗
NASA NTRS1981

A data base of geologic field spectra

It is noted that field samples measured in the laboratory do not always present an accurate picture of the ground surface sensed by airborne or spaceborne instruments because of the heterogeneous nature of most surfaces and because samples are disturbed and surface characteristics changed by collection and handling. The development of new remote sensing instruments relies on the analysis of surface materials in their natural state. The existence of thousands of Portable Field Reflectance Spectrometer (PFRS) spectra has necessitated a single, all-inclusive data base that permits greatly simplified searching and sorting procedures and facilitates further statistical analyses. The data base developed at JPL for cataloging geologic field spectra is discussed.

Kahle, A. B.↗
NASA NTRS1980

Back surface reflectors for solar cells

Sample solar cells were fabricated to study the effects of various back surface reflectors on the device performance. They are typical 50 micrometers thick, space quality, silicon solar cells except for variations of the back contact configuration. The back surfaces of the sample cells are polished to a mirror like finish, and have either conventional full contacts or grid finger contacts. Measurements and evaluation of various metallic back surface reflectors, as well as cells with total internal reflection, are presented. Results indicate that back surface reflectors formed using a grid finger back contact are more effective reflectors than cells with full back metallization and that Au, Ag, or Cu are better back surface reflector metals than Al.

Chai, A. T.↗
NASA NTRS1978

Conductivity of materials made of aluminum nitride and silicon nitride mixtures

To establish the possible mechanism for conductivity in aluminum nitride a study was made of the electric conductivity of pure AlN and its mixtures with silicon nitride at different temperatures and partial pressures of nitrogen in the gas phase. The thermoelectromotive force was also measured. The experiments used polycrystalline samples of cylindrical shape 18 mm in diameter made of powders by hot pressing in graphite press molds at a temperature of 1973-2273 K and pressure 1,470,000 n/sqm. The items obtained by this method had porosity not over 5%. After pressing, the samples were machined to remove carbon from the surface, and were annealed in a stream of dry ammonia for 10 h at a temperature of 1273-1373 K. Electric conductivity was measured according to the bridge scheme on an alternating current of frequency 10 kHz. In order to guarantee close contact of the platinum electrodes with the surface of the samples, a thin layer of platinum was sprayed on them. Experiments were conducted in the temperature interval 1273-1573 K with a half hour delay at each assigned temperature with heating and cooling.

Gorbatov, A. G.↗
NASA NTRS1995

Sub-ppb Oxygen Contaminant Detection in Semi-Conductor Processing

Gaseous contaminants such as oxygen, water vapor, nitrogen and hydrocarbons are often present in the processing environment in semiconductor device fabrication and in containerless materials processing. The contaminants arise as a result of outgassing from hot surfaces or they may be part of the impurities in commercial ultra-high purity gases. Among these gaseous contaminants, oxygen is the most reactive and, therefore, has the most adverse effects on the end product. There has been an intense effort at the Jet Propulsion Laboratory to develop different types of oxygen sorbents to reduce oxygen concentration in a microgravity processing environment to sub-ppb (parts-per-billion) levels. Higher concentrations can lead to rapid surface oxide formation, hence reducing the quality of semiconductor devices. If the concentration of oxygen in a processing chamber at 1000oC is in the ppb level, it will only take approximately 10 seconds for an oxide layer to form on the surface of a sample. The interaction of oxygen with the water surface can lead to the formation of localized defects in semi-conductor devices, hence decreasing the manufacturing yield. For example, efficient production of 64 Mb RAM chips requires contaminations below ppb levels. This paper describes a technique for measuring trace quantities of oxygen contaminants by recording the monoatomic negative ions, O-, using mass spectrometry. The O- formation from the e--O2 interaction utilizes the electron dissociative attachment method that is greatly enhanced at the resonant energy (6.8 eV). The device combines a small gridded electron ionizer with a compact mass spectrometer. The concentrations of oxygen have been measured using the method of standard additions by diluting O2 in N2. The lowest detection limit obtained was 1.2 kHz (O- count rate) at a concentration of 10-10, corresponding to 0.1 ppb.

Sub-ppb Contaminant↗
NASA NTRS2016

Electrostatic Discharge Testing of Carbon Composite Solar Array Panels for the Europa Mission to Jupiter

Carbon composite solar array panel coupons similar to those considered for use on the planned NASA Europa Mission were exposed to energetic electrons to observe the size and rate of electrostatic discharge production. The discharge size and rate were found to be primarily dependent on the quantity of dielectric binder pooled on the surface of the sample. Cooling the samples to cryogenic temperatures increased the size of discharges but an end of mission radiation dose had only minimal effects. Samples were composed of M55J carbon composite impregnated with an RS3 binder. Additional samples tested included a co-cured Kapton surface.

Green, Nelson W.↗