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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Nuclear thermal propulsion workshop overview

NASA is planning an Exploration Technology Program as part of the Space Exploration Initiative to return U.S. astronauts to the moon, conduct intensive robotic exploration of the moon and Mars, and to conduct a piloted mission to Mars by 2019. Nuclear Propulsion is one of the key technology thrust for the human mission to Mars. The workshop addresses NTP (Nuclear Thermal Rocket) technologies with purpose to: assess the state-of-the-art of nuclear propulsion concepts; assess the potential benefits of the concepts for the mission to Mars; identify critical, enabling technologies; lay-out (first order) technology development plans including facility requirements; and estimate the cost of developing these technologies to flight-ready status. The output from the workshop will serve as a data base for nuclear propulsion project planning.

Clark, John S.↗
NASA NTRS2013

Habitable Mars Ascent Vehicle (MAV) Concept

NASA's ultimate goal is the human exploration of Mars. Among the many difficult aspects of a trip to Mars is the return mission that would transport the astronauts from the Martian surface back into Mars orbit. One possible conceptual design to accomplish this task is a two-stage Mars Ascent Vehicle (MAV). In order to assess this design, a general layout and configuration for the spacecraft must be developed. The objective of my internship was to model a conceptual MAV design to support NASA's latest human Mars mission architecture trade studies, technology prioritization decisions, and mass, cost, and schedule estimates.

Dang, Victor↗
NASA NTRS1999

Characterization of Terrain in the Mars Surveyor 2001 Landing Site Latitude and Elevation Region Using Mapping Phase Mars Global Surveyor MOC Images

One of the original objectives of the Mars Orbiter Camera (MOC), as proposed in 1985, was to acquire observations to be used in assessing future spacecraft landing sites. Images obtained by the Mars Global Surveyor MOC since March 1999 provide the highest resolution views (1.5-4.5 m/pixel) of the planet ever seen. We have been examining these new data to develop a general view of what Mars is like at meter-scale within the latitudes and elevations that are accessible to the Mars Surveyor 2001 lander. Our goal is to provide guidance to the 2001 landing site selection process, rather than to use MOC images to recommend a specific landing site.

Malin, M. C.↗
NASA NTRS1989

Microbial mats in playa lakes and other saline habitats: Early Mars analog?

Microbial mats are cohesive benthic microbial communities which inhabit various Terra (Earth-based) environments including the marine littoral and both permanent and ephemeral (playa) saline lakes. Certain geomorphological features of Mars, such as the Margaritifer Sinus, were interpreted as ancient, dried playa lakes, presumably formed before or during the transition to the present Mars climate. Studies of modern Terran examples suggest that microbial mats on early Mars would have had the capacity to survive and propagate under environmental constraints that would have included irregularly fluctuating regimes of water activity and high ultraviolet flux. Assuming that such microbial communities did indeed inhabit early Mars, their detection during the Mars Rover Sample Return (MRSR) mission depends upon the presence of features diagnostic of the prior existence of these communities or their component microbes or, as an aid to choosing suitable landing, local exploration or sampling sites, geomorphological, sedimentological or chemical features characteristic of their playa lake habitats. Examination of modern Terran playas (e.g., the Lake Eyre basin) shows that these features span several orders of magnitude in size. While stromatolites are commonly centimeter-meter scale features, bioherms or fields of individuals may extend to larger scales. Preservation of organic matter (mats and microbes) would be favored in topographic lows such as channels or ponds of high salinity, particularly those receiving silica-rich groundwaters. These areas are likely to be located near former zones of groundwater emergence and/or where flood channels entered the paleo-playa. Fossil playa systems which may aid in assessing the applicability of this particular Mars analog include the Cambrian Observatory Hill Beds of the Officer Basin and the Eocene Wilkins Peak Member of the Green River Formation.

Bauld, John↗
NASA NTRS1991

Impact of Mars sand on dust on the design of space suits and life support equipment: A technology assessment

Space suits and life support equipment will come in intimate contact with Martian soil as aerosols, wind blown particles and material thrown up by men and equipment on the Martian surface. For purposes of this discussion the soil is assumed to consist of a mixture of cominuted feldspar, pyroxene, olivine, quartz, titanomagnetite and other anhydrous and hydrous iron bearing oxides, clay minerals, scapolite and water soluble chlorides and sulfates. The soil may have photoactivated surfaces that acts as a strong oxidizer with behavior similar to hydrogen peroxide. The existing data about the Mars soil suggests that the dust and sand will require designs analogous to those uses on equipment exposed to salty air and blowing sand and dust. The major design challenges are in developing high performance radiators which can be cleaned after each EVA without degradation, designing seals that are readily cleaned and possibly in selecting materials which will not be degraded by any strong oxidants in the soil. The magnitude of the dust filtration challenge needs careful evaluation in terms of the trade off between fine-particle dust filters with low pressure drop that are either physically large and heavy, like filter baghouses require frequent replacement of filter elements, of low volume high pressure thus power consumption approaches, or washable filters. In the latter, filter elements are cleaned with water, as could the outsides of the space suits in the airlock.

Simonds, Charles H.↗
NASA NTRS2004

High-Resolution Topomapping of Mars: Life After MER Site Selection

In this abstract we describe our ongoing use of high-resolution images from the Mars Global Surveyor Mars Orbiter Camera Narrow-Angle subsystem (MGS MOC-NA) to derive quantitative topographic and slope data for the martian surface at 3 - 10-m resolution. Our efforts over the past several years focused on assessment of candidate landing sites for the Mars Exploration Rovers (MER) and culminated in the selection of sites in Gusev crater and Meridiani Planum as safe as well as scientifically compelling. As of this writing, MER-A (Spirit) has landed safely in Gusev and we are performing a limited amount of additional mapping near the landing point to support localization of the lander and rover operations planning. The primary focus of our work, however, has been extending our techniques to sample a variety of geologic terrains planetwide to support both a variety of geoscientific studies and planning and data analysis for missions such as Mars Express, Mars Reconnaissance Orbiter, and Phoenix.

Kirk, R. L.↗
NASA NTRSDate not supplied

Expanding a Family of Mars Chemical Transportation Elements with a Large Vertical Lander Concept

In characterizing the trade space available for enabling human Mars missions, NASA’s Mars Architecture Team (MAT) has continues to developed a collection of concepts to assess the capabilities and constraints presented by a family of large Mars Chemical Transportation Elements (MACHETE). The purpose of this paper is to extend the MACHETE family with a new Large Vertical Lander (LVL) concept to increase our knowledge of the transportation trade space. The LVL is designed as a dedicated lander system capable of delivering a separate Mars Ascent Vehicle (MAV) fully-fueled to the surface of Mars. The addition of this concept enables exploring architecture alternatives that do not require either in-situ ascent propellant production or pre-deployment and subsequent surface transfer of ascent propellant.

Campaign↗
NASA NTRS1984

Design, development, performance, and reconditioning of Ni-Cd batteries using polyropylene separators

A performance assessment is made for the Viking Mars Lander Program's sealed, sterilizable, 8-ampere hour Ni-Cd batteries, which use a nonwoven polypropylene separator material. Attention is given to separator wettability, the optimization of electrolyte quantity, and the reduction of plate carbonate, in view of thermal considerations and other environmental design and test requirements generated by mission characteristics. Life data based on mission experience identify, in addition to performance and degradation behavior, a series of shallow discharge reconditioning cycles and an intensive program of deep discharge reconditioning.

Britting, A. O., Jr.↗
NASA NTRS1990

Benefits of electric propulsion for the Space Exploration Initiative

An overview of the benefits which may be derived through the use of electric propulsion in support of the Space Exploration Initiative is presented. Lunar cargo, Mars cargo and piloted Mars vehicles using electric propulsion are considered. The high performance of electric propulsion systems is shown to offer substantial benefits for these applications, including: substantially reduced initial masses in low earth orbit, reduced round-trip times for piloted Mars vehicles, availability of large amounts of electrical power en route and at the destination, less sensitivity to launch dates and windows, reusability, and growth potential for human exploration of the solar system. Hybrid chemical/NEP and NTR/NEP vehicles are discussed for their potential to reduce piloted round-trip time to Mars even further. A brief technology assessment of the major electric propulsion system components is also presented.

Brophy, John R.↗
NASA NTRS1991

Electrostatic fields in a dusty Martian environment

While there have been several studies suggesting the possibility of electrical activity on Mars, to date there have been no measurements to search for evidence of such activity. In the absence of widespread water clouds and convective storm systems similar to those on the Earth and Jupiter, the most likely candidate for the creation of electrostatic charges and fields is triboelectric charging of dust, i.e., the friction between blown dust and the ground, and of dust particles with each other. Terrestrial experience demonstrates that electric fields 5 to 15 kV-m(exp -1) are not uncommon in dust storms and dust devils in desert regions, where the polarity varies according to the chemical composition and grain size. Simple laboratory experiments have demonstrated that modest electrostatic fields of roughly 5,000 V-m(exp -1) may be produced, along with electrical spark discharges and glow discharges, in a simulation of a dusty, turbulent Martian surface environment. While the Viking landers operated for several years with no apparent deleterious effects from electrostatic charging, this may have been at least partly due to good engineering design utilizing pre-1976 electronic circuitry to minimize the possibility of differential charging among the various system components. However, free roaming rovers, astronauts, and airborne probes may conceivably encounter an environment where electrostatic charging is a frequent occurrence, either by way of induction from a static electric field or friction with the dusty surface and atmosphere. This raises the possibility of spark discharges or current surges when subsequent contact is made with other pieces of electrical equipment, and the possibility of damage to modern microelectronic circuitry. Measurements of electrostatic fields on the surface of Mars could therefore be valuable for assessing this danger. Electric field measurements could also be useful for detecting natural discharges that originate in dust storms. This detection could be performed at distances ranging from 10s of km in the case of J-charge-like discharge signatures, to planetary distances if there exists a global electrical circuit or Schumann resonance spectrum.

Sentman, D. D.↗
NASA NTRS2004

Evaporation Rates for Liquid Water and Ice Under Current Martian Conditions

A number of studies have been concerned with the evaporation rates under martian conditions in order to place limits on the possible survival time of both liquid water and ice exposed on the surface of Mars. Such studies also aid in assessing the efficacy of an overlying layer of dust or loose regolith material in providing a barrier to free evaporation and thus prolong the lifetime of water in locations where its availability to putative living organisms would be significant. A better quantitative understanding of the effects of phase changes of water in the near surface environment would also aid the evaluation of the possible role of water in the formation of currently observed features, such as gullies in cliff walls and relatively short-term changes in the albedo of small surface areas ('dark stains'). Laboratory measurements aimed at refinement of our knowledge of these values are described here. The establishment of accurate values for evaporation rates and their dependence on the physical conditions of temperature, pressure and energy input, is an important benchmark for the further investigation of the efficacy of barriers to free evaporation in providing a prolonged period of survival of the water, particularly as a liquid.

Sears, D. W. G.↗
NASA NTRS2004

A New Method for Estimating Bacterial Abundances in Natural Samples using Sublimation

We have developed a new method based on the sublimation of adenine from Escherichia coli to estimate bacterial cell counts in natural samples. To demonstrate this technique, several types of natural samples including beach sand, seawater, deep-sea sediment, and two soil samples from the Atacama Desert were heated to a temperature of 500 C for several seconds under reduced pressure. The sublimate was collected on a cold finger and the amount of adenine released from the samples then determined by high performance liquid chromatography (HPLC) with UV absorbance detection. Based on the total amount of adenine recovered from DNA and RNA in these samples, we estimated bacterial cell counts ranging from approx. l0(exp 5) to l0(exp 9) E. coli cell equivalents per gram. For most of these samples, the sublimation based cell counts were in agreement with total bacterial counts obtained by traditional DAPI staining. The simplicity and robustness of the sublimation technique compared to the DAPI staining method makes this approach particularly attractive for use by spacecraft instrumentation. NASA is currently planning to send a lander to Mars in 2009 in order to assess whether or not organic compounds, especially those that might be associated with life, are present in Martian surface samples. Based on our analyses of the Atacama Desert soil samples, several million bacterial cells per gam of Martian soil should be detectable using this sublimation technique.

Glavin, Daniel P.↗
NASA NTRS2001

The potential impact of bystander effects on radiation risks in a Mars mission

Densely ionizing (high-LET) galactic cosmic rays (GCR) contribute a significant component of the radiation risk in free space. Over a period of a few months-sufficient for the early stages of radiation carcinogenesis to occur-a significant proportion of cell nuclei will not be traversed. There is convincing evidence, at least in vitro, that irradiated cells can send out signals that can result in damage to nearby unirradiated cells. This observation can hold even when the unirradiated cells have been exposed to low doses of low-LET radiation. We discuss here a quantitative model based on the a formalism, an approach that incorporates radiobiological damage both from a bystander response to signals emitted by irradiated cells, and also from direct traversal of high-LET radiations through cell nuclei. The model produces results that are consistent with those of a series of studies of the bystander phenomenon using a high-LET microbeam, with the end point of in vitro oncogenic transformation. According to this picture, for exposure to high-LET particles such as galactic cosmic rays other than protons, the bystander effect is significant primarily at low fluences, i.e., exposures where there are significant numbers of untraversed cells. If the mechanisms postulated here were applicable in vivo, using a linear extrapolation of risks derived from studies using intermediate doses of high-LET radiation (where the contribution of the bystander effect may be negligible) to estimate risks at very low doses (where the bystander effect may be dominant) could underestimate the true risk from low doses of high-LET radiation. It would be highly premature simply to abandon current risk projections for high-LET, low-dose radiation; however, these considerations would suggest caution in applying results derived from experiments using high-LET radiation at fluences above approximately 1 particle per nucleus to risk estimation for a Mars mission.

Non-NASA Center↗
NASA NTRS2005

Internal Dynamics and Crustal Evolution of Mars

The objective of this work is to improve understanding of the internal structure, crustal evolution, and thermal history of Mars by combining geophysical data analysis of topography, gravity and magnetics with results from analytical and computational modeling. Accomplishments thus far in this investigation include: (1) development of a new crustal thickness model that incorporates constraints from Mars meteorites, corrections for polar cap masses and other surface loads, Pratt isostasy, and core flattening; (2) determination of a refined estimate of crustal thickness of Mars from geoid/topography ratios (GTRs); (3) derivation of a preliminary estimate of the k(sub 2) gravitational Love number and a preliminary estimate of possible dissipation within Mars consistent with this value; and (4) an integrative analysis of the sequence of evolution of early Mars. During the remainder of this investigation we will: (1) extend models of degree-1 mantle convection from 2-D to 3-D; (2) investigate potential causal relationships and effects of major impacts on mantle plume formation, with primary application to Mars; (3) develop exploratory models to assess the convective stability of various Martian core states as relevant to the history of dynamo action; and (4) develop models of long-wavelength relaxation of crustal thickness anomalies to potentially explain the degree-1 structure of the Martian crust.

Zuber, Maria↗
NASA NTRS2012

Space Weathering Investigations Enabled by NASA's Virtual Heliophysical Observatories

Structural and chemical impact of the heliospheric space environment on exposed planetary surfaces and interplanetary dust grains may be generally defined as space weathering . In the inner solar system, from the asteroid belt inwards towards the Sun, the surface regolith structures of airless bodies are primarily determined by cumulative meteoritic impacts over billions of years, but the molecular composition to meters in depth can be substantially modified by irradiation effects. Plasma ions at eV to keV energies may both erode uppermost surfaces by sputtering, and implant or locally produce exogenic material, e.g. He-3 and H2O, while more energetic ions drive molecular change through electronic ionization. Galactic cosmic ray ions and more energetic solar ions can impact chemistry to meters in depth. High energy cosmic ray interactions produce showers of secondary particles and energetic photons that present hazards for robotic and human exploration missions but also enable detection of potentially useable resources such as water ice, oxygen, and many other elements. Surface sputtering also makes ejected elemental and molecular species accessible for in-situ compositional analysis by spacecraft with ion and neutral mass spectrometers. Modeling of relative impacts for these various space weathering processes requires knowledge of the incident species-resolved ion flux spectra at plasma to cosmic ray energies and as integrated over varying time scales. Although the main drivers for investigations of these processes come from NASA's planetary science and human exploration programs, the NASA heliophysics program provides the requisite data measurement and modeling resources to enable specification of the field & plasma and energetic particle irradiation environments for application to space weather and surface weathering investigations. The Virtual Heliospheric Observatory (VHO), Virtual Energetic Particle Observatory (VEPO), Lunar Solar Origins Exploration (LunaSOX), and Space Physics Data Facility (SPDF) services now provide a wide range of inner heliospheric spacecraft data that can be applied to space weathering of potential exploration destinations including the Moon, asteroids, and the moons of Mars, as well to radiation hazard assessment for the spacecraft and human explorers. For example, the new VEPO service for time-averaging of multi-source ion flux spectra enables the specification of composite flux spectra from a variety of ongoing and legacy missions for applications to surface interaction modeling. Apollo to Artemis data resources of LunaSOX enable specific space weathering investigations for the Moon, while VHO more generally covers the space field and plasma environments of the inner and outer solar system from the sunward-most perihelia of the twin Helios spacecraft to the ongoing heliosheath passages of the twin Voyagers. Composite multi-source spectra from VEPO can also be applied to the continuing compilation of accumulated 1-AU fluence spectra, mostly contributed by solar wind plasma and energetic particle events, for determination of time-averaged particle compositional and kinetic energy output from the Sun and for modeling of long-term irradiation impacts on planetary surfaces.

Cooper, John F.↗
NASA NTRS2019

Mars Ascent Vehicle (MAV) Solid Motor Technology Plans

Recent trades have taken place on solid propulsion options to support a potential Mars Sample Retrieval Campaign. Mass and dimensional requirements for a Mars Ascent Vehicle (MAV) are being assessed. One MAV vehicle concept would utilize a solid propulsion system. Key challenges to designing a solid propulsion system for MAV include low temperatures beyond common tactical and space requirements, performance, planetary protection, mass limits, and thrust vector control system. Two solutions are addressed, a modified commercial commercially available system, and an optimum new concept.

Prince, Andrew↗