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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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NASA NTRS1995

The Widest Practicable Dissemination: The NASA Technical Report Server

The National Aeronautics and Space Act of 1958 established NASA and charged it to "provide for the widest practicable and appropriate dissemination of information concerning [...] its activities and the results thereof." The search for innovative methods to distribute NASA s information lead a grass-roots team to create the NASA Technical Report Server (NTRS), which uses the World Wide Web and other popular Internet-based information systems as search engines. The NTRS is an inter-center effort which provides uniform access to various distributed publication servers residing on the Internet. Users have immediate desktop access to technical publications from NASA centers and institutes. The NTRS is comprised of several units, some constructed especially for inclusion in NTRS, and others that are existing NASA publication services that NTRS reuses. This paper presents the NTRS architecture, usage metrics, and the lessons learned while implementing and maintaining the services over the initial 6-month period. The NTRS is largely constructed with freely available software running on existing hardware. NTRS builds upon existing hardware and software, and the resulting additional exposure for the body of literature contained will allow NASA to ensure that its institutional knowledge base will continue to receive the widest practicable and appropriate dissemination.

Nelson, Michael L.↗
NASA NTRS1995

The NASA Technical Report Server

The National Aeronautics and Space Act of 1958 established NASA and charged it to "provide for the widest practicable and appropriate dissemination of information concerning its activities and the results thereof." The search for innovative methods to distribute NASA's information lead a grass-roots team to create the NASA Technical Report Server (NTRS), which uses the World Wide Web and other popular Internet-based information systems as search engines. The NTRS is an inter-center effort which provides uniform access to various distributed publication servers residing on the Internet. Users have immediate desktop access to technical publications from NASA centers and institutes. The NTRS is comprised of several units, some constructed especially for inclusion in NTRS, and others that are existing NASA publication services that NTRS reuses. This paper presents the NTRS architecture, usage metrics, and the lessons learned while implementing and maintaining the service. The NTRS is largely constructed with freely available software running on existing hardware. NTRS builds upon existing hardware and software, and the resulting additional exposure for the body of literature contained ensures that NASA's institutional knowledge base will continue to receive the widest practicable and appropriate dissemination.

Nelson, Michael L.↗
NASA NTRS2013

Electrodynamic Dust Shield Demonstrator

The objective of the project was to design and manufacture a device to demonstrate a new technology developed by NASA's Electrostatics and Surface Physics Laboratory. The technology itself is a system which uses magnetic principles to remove regolith dust from its surface. This project was to create an enclosure that will be used to demonstrate the effectiveness of the invention to The Office of the Chief Technologist. ONE of the most important challenges of space exploration is actually caused by something very small and seemingly insignificant. Dust in space, most notably on the moon and Mars, has caused many unforeseen issues. Dirt and dust on Earth, while a nuisance, can be easily cleaned and kept at bay. However, there is considerably less weathering and erosion in space. As a result, the microscopic particles are extremely rough and abrasive. They are also electrostatically charged, so they cling to everything they make contact with. This was first noted to be a major problem during the Apollo missions. Dust would stick to the spacesuits, and could not be wiped off as predicted. Dust was brought back into the spacecraft, and was even inhaled by astronauts. This is a major health hazard. Atmospheric storms and other events can also cause dust to coat surfaces of spacecraft. This can cause abrasive damage to the craft. The coating can also reduce the effectiveness of thermal insulation and solar panels.' A group of engineers at Kennedy Space Center's Electrostatics and Surface Physics Laboratory have developed a new technology, called the Electrodynamic Dust Shield, to help alleviate these problems. It is based off of the electric curtain concept developed at NASA in 1967. "The EDS is an active dust mitigation technology that uses traveling electric fields to transport electrostatically charged dust particles along surfaces. To generate the traveling electric fields, the EDS consists of a multilayer dielectric coating with an embedded thin electrode grid running a multiphase low frequency AC signal. Electrostatically charged particles, such as those encountered on the moon, Mars, or an asteroid, are carried along by the traveling field due to the action of Coulomb and dielectrophoretic forces."2 The technical details have been described in a separate article. This document details the design and construction process of a small demonstration unit. Once finished, this device will go to the Office of the ChiefTechnologist at NASA headquarters, where it will be used to familiarize the public with the technology. 1 NASA KSC FO Intern, Prototype Development Laboratory, Kennedy Space Center, University of Central Florida Kennedy Space

Stankie, Charles G.↗
NASA NTRS2001

New measurements for hadrontherapy and space radiation: biology

The dual goals of optimizing clinical efficacy of hadrontherapy and determining radiation risk estimates for space research have intersected to a common focus for investigation of the biological effects of charged particles. This paper briefly highlights recent international progress at accelerator facilities engaged in both biological and clinical studies of the effects of particle beams, primarily protons, carbon and iron ions. Basic mechanisms of molecular, cellular and tissue responses continue under investigation for radiations with a range of ionization densities. Late normal tissue effects, including the risk of cancer in particular, are of importance for both research fields. International cooperation has enhanced the rate of progress as evidenced by recent publications. Specific areas of biomedical research related to the biological radiotoxicity of critical organs (especially the central nervous system), individual radiosensitivities to radiation carcinogenesis, and the analysis of effects in mixed radiation fields still require more research. Recommendations for addressing these issues are made.

Review↗
NASA NTRS2021

Electron Energy Interplay in the Geomagnetic Trap Below the Auroral Acceleration Region

This publication addresses the collisional superthermal electron dynamics below the auroral acceleration region (AAR). This region is the portion of an auroral field line with a field-aligned electric field that leads to the formation of precipitating monoenergetic keV electron fluxes that produce the discrete auroral displays observable from the ground. It is assumed that these precipitating electron fluxes are monoenergetic and accelerated through a potential drop, V, such that these electrons are peaked at an energy E0 = eV, where e is the electron charge. Monoenergetic electrons precipitating into the upper atmosphere degrade to lower energies via many different collisional processes and produce the secondary electron population with energies of 10–100s eV which escapes back to magnetospheric altitudes and becomes geomagnetically trapped between the AAR and the upper ionosphere. The secondary electrons in this geomagnetic trap transfer energy via elastic Coulomb collisions to the thermal electrons. That energy is then returned to the topside ionosphere as heat flux carried by the electron thermal conduction which is essential to maintaining the topside electron temperature.

George V Khazanov↗
NASA NTRS1982

The thermohaline driving mechanism of oceanic jet streams

In a series of publications dealing with the circulation of the North Atlantic, Worthington (1959, 1972, 1976, 1977) has challenged the widely accepted notion that the Gulf Stream system is entirely wind-driven. He was able to demonstrate that the Gulf Stream over its most intense portion south of New England generally intensifies in winter. Worthington postulates that strong surface cooling in winter is the cause of Gulf Stream intensification, i.e., he believes that a thermal mechanism is partially responsible for driving the Gulf Stream. Worthington speaks of 'anticyclogenesis' and of a 'fresh charge of energy' which the Gulf Stream receives at the end of each (severe) winter. A pattern of thermoline circulation arising in the upper layers of the Stream could play a role similar to that of the Hadley circulation in the atmosphere, which derives the subtropical jet stream. The present investigation is concerned with the examination of such a possibility, taking into account the employment of a two-layer model.

Csanady, G. T.↗
NASA NTRS1988

Design guide: Designing and building high voltage power supplies, volume 2

This report contains an accumulation of publications and analyses aimed at developing guidelines for improving both high voltage and low voltage power supplies for the U.S. Air Force systems command. It is the intent of the report to supply good design and manufacturing techniques for the packaging and the building of high quality, reliable, long-life power supplies. These data are based on the wealth of engineering practices established by design and manufacturing engineers. The contents are: Fundamentals of Insulation: Gases, Liquid Dielectrics, Solid Insulation; Environment: Pressure, Particulates, Environmental Interactions with Space Power Systems, Surface Charging, System Design Criteria; Configuration and Design Data: Designs, Transients, Grounding and Bonding, Thermal Control; Materials and Processes: Insulation, Processes, Process Variables; Manufacturing: Yield, Government and Industrial Survey, Analysis, Problem Areas and Suggested Solutions, Designs That Have Worked in High Voltage Equipment, Manufacturing Summary; and Tests: Performance, Insulation Tests, Materials Testing, Component and Equipment Tests, Performance Testing, Facility and Environment, Accelerated Life Test; Maintenance and Repair: Maintenance, Test Sets, Pilots and Crewmen, Air Logistic Centers, Design Problem Recommendations.

W G Dunbar↗
NASA NTRS2006

Working Group Reports and Presentations: Cis-lunar

Space agencies are committed to the "safe, sustained, affordable human and robotic exploration of the Moon, Mars, and beyond." However, we recommend that they explicitly define our ultimate goal and motivation in order to portray a sense of purpose to the public. Our goal is sustainable human settlement of the Moon and Mars and our motivation is to preserve the human race. All secondary exploration and science objectives flow from this main goal and are still imperative to our success. As an economic guiding principle, governments should be limited to those areas where only government can perform the activity and should recognize and coordinate with the larger private and military sectors. Also, space agencies must continue to fund the interdisciplinary science necessary to characterize environmental hazards associated with dust, radiation, surface charging, topology, and meteorites in order to make our first attempts at extraterrestrial living viable.

Laubscher, Bryan↗
NASA NTRS2018

Internship in Augmented and Virtual Reality - Rapid Model Import Tool

The integration of virtual and augmented reality, sometimes called mixed reality, is an emerging technology which will likely skyrocket overnight much in the way smartphones did a decade ago. Kennedy Space Center's Augmented and Virtual Reality (AVR) Lab is developing a Rapid Model Import Tool (RMIT) to create a quick and efficient way to bring NASA's complex engineering 3D models into virtual and augmented environments. The long-term objective is to create a tool that will ultimately benefit KSC engineers. Its various uses within NASA can potentially span from astronaut training, to marketing, to public outreach, to name a few. Unity is a prolific cross-platform game engine that allows users to build high quality 2D and 3D games for desktop, mobile, web, and game console platforms. It is perhaps also the most widely used software for virtual reality game development. At the AVR lab, we are looking at alternative uses of Unity to build tools for NASA engineers to perform design, development, testing, and training on spacecraft, rocket delivery systems, ground support equipment, and facilities at KSC. As an intern for the RMIT project, I am charged with the task of performing research on Unity-compatible file types to develop an efficient, affordable, preservative process to bring models from CATIA 3D engineering software into the Unity environment. With a tool called the NASA Enterprise Visualization Application (NEVA), developed by the Boeing Design Visualization group at KSC, we are able to easily convert CATIA's design models to. DAE (also known as COLLADA) and .OBJ file formats. I first reduce the polygon count of the model within CATIA itself, make any necessary tweaks to reduce the model further, and then export using NEVA. The .OBJ or. DAE files that I am left with are then converted by another intern to a Unity-compatible file format using a custom Python script. I have generated extensive documentation of this process in a NEVA User Guide. By the end of this semester, we will have built a solid framework for RMIT based on a thorough understanding of virtual reality specifications and file requirements, allowing future software development teams to go forward with development on the custom tool.

Leap Motion↗
NASA NTRSDate not supplied

Uncrewed Lunar Surface Operations and Support Activities

Sustained human presence on the surface of the Moon and future missions to Mars require increased independence from surface crews and Earth-based mission control to operate efficiently, safely, and reliably. The time for surface crews to perform tasks will be limited. Extravehicular activities by surface personnel are burdensome and time-consuming, even when a continuous human presence on the surface occurs. Identifying and balancing human/automation roles and tasks and infusing automation and autonomy practices early in a system’s lifecycle will be essential to achieve mission objectives. Among these objectives are attaining a sustained human presence, improving performance and mission effectiveness, reducing operations and maintenance (O&M) costs, and ensuring operations that are robust to communication delays. To achieve these objectives, an operational shift toward increased automation and autonomy with less reliance on humans is needed. Uncrewed lunar surface operations and support activities occur when surface crews are not present or are independent of surface crew timeline activities requiring no surface crew oversight or intervention. These uncrewed surface opportunities can also be planned to minimize crew workload that avoids routine maintenance and support tasks, thus maximizing crew exploration time. Uncrewed preparations such as staging and prepositioning equipment and materials before the crew arrives could improve crew task efficiency. Additional opportunities exist to conduct uncrewed science, exploration, and utilization. Uncrewed surface architecture functions can include science and exploration; habitation; launch and landing support; surface communication and navigation; surface power generation and distribution; human surface mobility; lifting, handling, manipulating; excavation, construction, and site preparation; logistics management; maintenance and repair; surface resource utilization; integrated site operations and shared support services (e.g., site scheduling/prioritization, dust mitigation/contamination control, and surface safety). Early robotic lunar surface campaigns will provide information on the availability of resources, such as oxygen and water, and demonstrate surface-based technologies. After the Artemis III human lunar return mission, a series of landers will deliver surface systems, cargo, supplies, science packages, spare parts, and commodities. A balance of crewed and uncrewed surface operations will enable a sustained lunar surface presence at the South Pole of the Moon at a site that will be known as the Artemis Base Camp (ABC). It is envisioned that base camp operations on and around the Moon will then help prepare for the mission durations and activities needed to support the first human mission to Mars. Before long-duration crew missions to the base camp can occur, the necessary surface infrastructure will be pre-deployed and verified operational. Surface assets will be teleoperated and remotely managed from Earth. Additionally, robotic and short-duration crewed missions to the ABC will ensure the site’s merit to achieve long-term science objectives, availability of usable resources, and that terrain, seasonal variations, and illumination conditions are acceptable. ABC will consist of different areas where specific functions and services are rendered, including: • Launch and Landing Area • Habitation Area • Power Production Area • Resource Areas Launch and Landing Area—The launch and landing area will support associated functions for the arrival and departure of vehicles, such as crewed landing and ascent and uncrewed cargo deliveries and offloading. It will evolve from an unimproved site at the beginning of the exploration campaign to a more sustainable landing and launch area that can support repeated arrivals and departures. Initial uncrewed Lunar Terrain Vehicle (LTV) surface operations may include emplacement of navigation beacons and communication equipment, real-time video and photography of landing/liftoff events, and element repositioning, such as portable utility power (PUP) (applicable for other landed assets at other areas). Site preparations, such as surface leveling, soil compaction, and berm/path construction, may be needed for a more sustainable launch and landing area capable of accommodating vehicles that are increasingly more reusable and reduce the effects of plume surface interactions and ejecta impacts on nearby surface assets. During the ABC missions, cargo and logistics will be delivered to the lunar surface via robotic cargo landers before the crew arrives. These shipments, which can arrive in pressurized logistics carriers, will deliver the logistics necessary to support a crewed mission and include items such as food, water, equipment spares, etc. Providing the capability to retrieve, offload, and transport the logistics closer to the ABC site before the arrival of the crew will increase the overall efficiency of crew operations once they arrive. In the sustained phase of exploration, other supporting services may be needed, such as lander propellant servicing, surface power services, commodity refreshes, and additional inspection, maintenance, and repair capabilities, to sustain a cadence of extended personnel stays and cargo arrivals and departures. Habitation Area—Uncrewed support to surface habitation could involve supporting activation and pre-entry operations of the habitat while the crew is in orbit at the Gateway outpost preparing for a surface landing. Surface Habitat (SH) uncrewed operations may include bringing the cabin environment to a habitable temperature and air mix and activating other critical crew support systems. Potential crop production uncrewed tasks in the SH could also include autonomous watering and tending. Additionally, when the crew departs, the SH enters dormancy for the long period of uncrewed operation. A logistical staging area could also be collocated near the SH. If so, staging operations for crew supplies, waste re-location, and recycling operations may be opportunities for uncrewed operations. Power Production Area—The Fission Surface Power (FSP) element and its supporting distribution equipment provide power to surface elements as needed across the ABC to supplement day-to-day operations and survive lunar nights. Uncrewed support of this power system includes any initial LTV-assisted deployments of cables and other distributed equipment, associated electrical connections, and system testing and activation operations. Robotically performing some inspections, maintenance, or repair tasks on the power distribution equipment could reduce the surface crew workload. Resource Area— Uncrewed resource prospecting, mapping, and characterizing possible resource sites is likely to be time-consuming and represents an opportunity for uncrewed operations between crewed missions. Uncrewed mobile equipment operations will be needed in the extreme environments of permanently shadowed locations where resource extractions occur. As In-Situ Resource Utilization (ISRU) pilot plant operations begin, uncrewed surface support activities with available mobile and portable assets (LTV, PUP, etc.) will better support these operations. Any produced commodities can be stored at a centralized storage location for future use. Also associated with these operations is the use of mobile robotic excavators for resource acquisition and robotic/autonomous regolith processing. The waste tailings generated during excavation and regolith processing would also need to be transported and deposited at a dedicated location. Surface assets will continue operating between crew visits to maintain surface capabilities, conduct lunar surface science, technology demonstrations, and public outreach opportunities. Additionally, certain sustaining tasks that would consume valuable crew time could be performed before crew arrival, or after their departure. This capability may offer more affordable options to construct, activate, test, and maintain a broad set of surface assets. Telerobotically operated human surface mobility systems, such as the LTV and Pressurized Rover (PR), can be utilized for various tasks. Surface environmental conditions pose a distinct challenge for all these activities. Surface illumination and localized shadows are one such factor. Night-survival operations could consist of thermal management, battery pre-charging, and load shedding. Some surface systems may hibernate through the night and then awake and continue nominal operations. Uncrewed mobile assets may use a more adaptive approach to optimize their power and operations; one method is to follow the sunlight. Night-survival operations may be initiated remotely by teleoperation, automated, or accomplished by supervised autonomous operation. The ability to pre-deploy and control remote assets in orbit or on Mars before the arrival of the mission crew is a key capability that can be simulated on the moon. The base camp provides a venue where these advanced operational concepts, technologies, and autonomous methods and techniques, including the incorporation of time delays to simulate Earth-Mars latency can be replicated to help buy down future Mars mission risks. This paper will examine the evolution of uncrewed lunar surface operations and support activities. It will also discuss the lunar surface environmental conditions (thermal, lighting, terrain, topography, communications) along with the challenges they pose on uncrewed surface operations, and the performance of these activities with limited to minimal human interaction and/or teleoperation. Since lunar missions include Mars mission analogs, such investigation provides the framework for future uncrewed Mars mission support.

Mark E Lewis↗
NASA NTRS1991

Thunderstorm detection and warning system atmospheric potential monitor

An new type of electric field instrumentation was developed for lighting prediction at KSC. Currently, it is being installed at several government laboratories and is being made available to the public. It has important advantages over the previous method for measuring electric fields with motor driven field mills: (1) it has no moving parts and requires little maintenance compared to rotating machinery; (2) it is unaffected by rain, snow, sand, or insects, all of which can influence field mills; and (3) the lightweight sensor can be mounted easily on a tall mast. By mounting the instrumentation on a tall mast the instrumentation is placed above much of the blanket of point discharge ions that are emitted from objects on the ground during thunderstorms. This space charge limits the ability of any ground based electric field sensor to accurately measure cloud electric fields which produce lightning. The elevated mounting was demonstrated to significantly improve monitoring of thunderstorm electric fields. This instrumentation measures the atmospheric potential relative to earth at a corona needle sensor on top of a mast which normally is mounted on a tower or roof. The needle is kept in corona at all times by a low power high voltage power supply. This produces a small cloud of ions around the needle allowing a current to flow. Measurement of the current provides the atmospheric potential. The potential divided by the height of the needle above the ground is proportional to the average electric field between the needle and earth. The potential on top of a tall pole or above a rooftop is more representative of the intensity of cloud electrification than electric field measurements made at ground level. Photographs that depict the computer terminal, video display of a two sensor system, and the individual components installed on a tower are presented.

Source record↗
NASA NTRS2018

The Hitomi X-Ray Observatory, Part 2

When it was launched on 17 February 2016, the Hitomi X-ray Observatory carried four kinds of new-generation x-ray instruments—the Soft X-ray Spectrometer (SXS), the Soft X-ray Imager (SXI), the Hard X-ray Imager (HXI), and the Soft Gamma-ray Detector (SGD). All four instruments were turned on and were in the process of activation at the time of loss of contact on 26 March 2016. In the time it was operational, Hitomi was able to provide researchers with a trove of ground-breaking scientific results. Initial results demonstrated that the instruments were meeting or exceeding requirements and that Hitomi was on its way to pioneering a new era of broad-band and high-resolution x-ray spectroscopy. The results published here summarize the in-flight instrument performance, calibration, and data processing accomplishments of the observatory. Of the papers accepted for publication in this special section, 17 were presented in Part 1 in the January-March 2018 issue of JATIS (Journal of Astronomical Telescopes, Instruments, and Systems). Ten more papers are presented here as Part 2 in the April-June 2018 issue. These papers cover the detailed in-flight performance of the four state-of the-art instruments on-board the Hitomi X-Ray Observatory. These instruments were extremely diverse in their design and principles of operation, ranging from low temperature x-ray calorimeters for high-resolution spectroscopy, CCDs (Charge-Coupled Devices) for wide field imaging, high fill-factor grazing incidence x-ray optics, including multilayer x-ray optics and silicon strip and CdTe strip detectors for high-energy imaging, and a Si/CdTe Compton cameras for extending the bandpass out to 600 kiloelectronvolts. All of these instruments operated as expected and for sufficient time to validate their operating principles and carry out first light scientific investigations, published elsewhere. Collectively, these instruments, all co-aligned and operated simultaneously, provided a tool for astronomers with unprecedented resolution and broadband sensitivity for investigating high-energy processes throughout the universe. These papers serve as part of the Hitomi legacy and will guide the next generation of instruments planned for future missions.

Kelley, Richard L.↗
NASA NTRS2023

Direct Measurement of the Spectral Structure of Cosmic-Ray Electrons+Positrons in the Tev Region With Calet on the International Space Station

Detailed measurements of the spectral structure of cosmic-ray electrons and positrons from 10.6 GeV to 7.5 TeV are presented from over 7 years of observations with the CALorimetric Electron Telescope (CALET) on the International Space Station. The instrument, consisting of a charge detector, an imaging calorimeter, and a total absorption calorimeter with a total depth of 30 radiation lengths at normal incidence and a fine shower imaging capability, is optimized to measure the all-electron spectrum well into the TeV region. Because of the excellent energy resolution (a few percent above 10 GeV) and the outstanding e/p separation (10 5 ), CALET provides optimal performance for a detailed search of structures in the energy spectrum. The analysis uses data up to the end of 2022, and the statistics of observed electron candidates has increased more than 3 times since the last publication in 2018. By adopting an updated boosted decision tree analysis, a sufficient proton rejection power up to 7.5 TeV is achieved, with a residual proton contamination less than 10%. The observed energy spectrum becomes gradually harder in the lower energy region from around 30 GeV, consistently with AMS-02, but from 300 to 600 GeV it is considerably softer than the spectra measured by DAMPE and Fermi-LAT. At high energies, the spectrum presents a sharp break around 1 TeV, with a spectral index change from −3.15 to −3.91, and a broken power law fitting the data in the energy range from 30 GeV to 4.8 TeV better than a single power law with 6.9 sigma significance, which is compatible with the DAMPE results. The break is consistent with the expected effects of radiation loss during the propagation from distant sources (except the highest energy bin). We have fitted the spectrum with a model consistent with the positron flux measured by AMS-02 below 1 TeV and interpreted the electron+positron spectrum with possible contributions from pulsars and nearby sources. Above 4.8 TeV, a possible contribution from known nearby supernova remnants, including Vela, is addressed by an event-by-event analysis providing a higher proton-rejection power than a purely statistical analysis.

O. Adriani↗
NASA NTRS1993

Coulomb effects in low-energy nuclear fragmentation

Early versions of the Langley nuclear fragmentation code NUCFRAG (and a publicly released version called HZEFRG1) assumed straight-line trajectories throughout the interaction. As a consequence, NUCFRAG and HZEFRG1 give unrealistic cross sections for large mass removal from the projectile and target at low energies. A correction for the distortion of the trajectory by the nuclear Coulomb fields is used to derive fragmentation cross sections. A simple energy-loss term is applied to estimate the energy downshifts that greatly alter the Coulomb trajectory at low energy. The results, which are far more realistic than prior versions of the code, should provide the data base for future transport calculations. The systematic behavior of charge-removal cross sections compares favorably with results from low-energy experiments.

Wilson, John W.↗
NASA NTRS1992

Setting Priorities for Space Research: Opportunities and Imperatives

This report represents the first phase of a study by a task group convened by the Space Studies Board to ascertain whether it should attempt to develop a methodology for recommending priorities among the various initiatives in space research (that is, scientific activities concerned with phenomena in space or utilizing observations from space). The report argues that such priority statements by the space research community are both necessary and desirable and would contribute to the formulation and implementation of public policy. The report advocates the establishment of priorities to enhance effective management of the nation's scientific research program in space. It argues that scientific objectives and purposes should determine how and under what circumstances scientific research should be done. The report does not take a position on the controversy between advocates of manned space exploration and those who favor the exclusive use of unmanned space vehicles. Nor does the report address questions about the value or appropriateness of Space Station Freedom or proposals to establish a permanent manned Moon base or to undertake a manned mission to Mars. These issues lie beyond the charge to the task group.

Dutton, John A.↗
NASA NTRS1991

Cellular track model of biological damage to mammalian cell cultures from galactic cosmic rays

The assessment of biological damage from the galactic cosmic rays (GCR) is a current interest for exploratory class space missions where the highly ionizing, high-energy, high-charge ions (HZE) particles are the major concern. The relative biological effectiveness (RBE) values determined by ground-based experiments with HZE particles are well described by a parametric track theory of cell inactivation. Using the track model and a deterministic GCR transport code, the biological damage to mammalian cell cultures is considered for 1 year in free space at solar minimum for typical spacecraft shielding. Included are the effects of projectile and target fragmentation. The RBE values for the GCR spectrum which are fluence-dependent in the track model are found to be more severe than the quality factors identified by the International Commission on Radiological Protection publication 26 and seem to obey a simple scaling law with the duration period in free space.

Cucinotta, Francis A.↗
NASA NTRS2011

Saturn's Magnetosphere Interaction with Titan for T9 Encounter: 3D Hybrid Modeling and Comparison with CAPS Observations

Global dynamics of ionized and neutral gases in the environment of Titan plays an important role in the interaction of Saturn s magnetosphere with Titan. Several hybrid simulations of this problem have already been done (Brecht et al., 2000; Kallio et al., 2004; Modolo et al., 2007a; Simon et al., 2007a, 2007b; Modolo and Chanteur, 2008). Observational data from CAPS for the T9 encounter (Sittler et al., 2009) indicates an absence of O(+) heavy ions in the upstream that change the models of interaction which were discussed in current publications (Kallio et al., 2004; Modolo et al., 2007a; Simon et al., 2007a, 2007b; Ma et al., 2007; Szego et al., 2007). Further analysis of the CAPS data shows very low density or even an absence of H(+) ions in upstream. In this paper we discuss two models of the interaction of Saturn s magnetosphere with Titan: (A) high density of H(+) ions in the upstream flow (0.1/cu cm), and (B) low density of H(+) ions in the upstream flow (0.02/cu cm). The hybrid model employs a fluid description for electrons and neutrals, whereas a particle approach is used for ions. We also take into account charge-exchange and photoionization processes and solve self-consistently for electric and magnetic fields. The model atmosphere includes exospheric H(+), H(2+), N(2+)and CH(4+) pickup ion production as well as an immobile background ionosphere and a shell distribution for active ionospheric ions (M(sub i)=28 amu). The hybrid model allows us to account for the realistic anisotropic ion velocity distribution that cannot be done in fluid simulations with isotropic temperatures. Our simulation shows an asymmetry of the ion density distribution and the magnetic field, including the formation of Alfven wing-like structures. The results of the ion dynamics in Titan s environment are compared with Cassini T9 encounter data (CAPS).

Lipatov, A. S.↗
NASA NTRS1994

Charge collection during hypervelocity penetrations of thin foils

The following represents trajectory sensor development work for the space-station-based Cosmic Dust Collection Facility (CDCF). This facility-class payload was to expose some 7 sq m of NASA-provided general-user instruments in addition to three instruments provided by formally selected principal investigators. The preferred trajectory sensor for this general-user instrument envisioned the detection of impact-triggered plasma for both velocity measurement and location instruments. Space station developments in late 1992/early 1993 lead to cancellation of this potential flight project, for both technical and fiscal reasons. This precipitated termination of all plasma detection work at JSC on behalf of CDCF's general-user instrument. The following comprises three informal reports that summarize the CDCF efforts regarding plasma sensing for trajectory determinations. The reports were initially written for internal CDCF use and were not widely distributed. Because no formal publications are envisioned at present, the three reports are included in full in this document. They not only demonstrate that substantial progress was accomplished in the development of plasma trajectory sensors during 1990-1992, but the results are hopefully of interest and use to others who may continue these developments. The chronological sequence of these three reports is reversed, with the first containing the latest information.

Peterson, Robert B.↗