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NASA NTRS1982

Matter in general relativity

Two theories of matter in general relativity, the fluid theory and the kinetic theory, were studied. Results include: (1) a discussion of various methods of completing the fluid equations; (2) a method of constructing charged general relativistic solutions in kinetic theory; and (3) a proof and discussion of the incompatibility of perfect fluid solutions in anisotropic cosmologies. Interpretations of NASA gravitational experiments using the above mentioned results were started. Two papers were prepared for publications based on this work.

Ray, J. R.↗

NASA NTRS2013

Study of the Effects of the Electric Field on Charging Measurements on Individual Micron-size Dust Grains by Secondary Electron Emissions

The dust charging by electron impact is an important dust charging process in Astrophysical, Planetary, and the Lunar environments. Low energy electrons are reflected or stick to the grains charging the dust grains negatively. At sufficiently high energies electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). Available theoretical models for the calculation of SEE yield applicable for neutral, planar or bulk surfaces are generally based on Sternglass Equation. However, viable models for charging of individual dust grains do not exist at the present time. Therefore, the SEE yields have to be obtained by some experimental methods at the present time. We have conducted experimental studies on charging of individual micron size dust grains in simulated space environments using an electrodynamic balance (EDB) facility at NASA-MSFC. The results of our extensive laboratory study of charging of individual micron-size dust grains by low energy electron impact indicate that the SEE by electron impact is a very complex process expected to be substantially different from the bulk materials. It was found that the incident electrons may lead to positive or negative charging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration. In this paper we give a more elaborate discussion about the possible effects of the AC field in the EDB on dust charging measurements by comparing the secondary electron emission time-period (tau (sub em) (s/e)) with the time-period (tau (sub ac) (ms)) of the AC field cycle in the EDB that we have briefly addressed in our previous publication.

Tankosic, D.↗

NASA NTRS2023

Lunar Dust Mitigation: A Guide and Reference: First Edition (2021)

On the surface of the Moon, lunar dust specifically presents unique challenges to operations long-term due to regolith particles’ ubiquitous presence in the lunar environment, potential to electrostatically charge and possible chemical reactivity. Whether to avoid exposure, try to remove or simply to tolerate lunar dust infiltrating a system becomes a complex question involving length of required service life, dust effects and critical risks, mass and complexity trades for the entire system. This publication provides a snapshot of advice from topical experts for specific areas of concern to systems targeted for deployment on the lunar surface. Following introductory overview commentary, dust mitigation approaches appropriate to the lunar surface are first addressed for typically static structures such as optical surfaces, radiators, and other thermal control surfaces, followed by regolith exposure concerns for communications equipment and non-optical sensors. The broad topic of mechanisms and mechanical assemblies is broken down to address relevant component level concerns, such as for bearings and for seals. “Soft goods” components of space suits (fabric) specific concerns are discussed, followed finally by brief coverage of human health issues and concerns, though the emphasis of this publication remains with components directly exposed to the harsh lunar surface environment. A description of some lunar surface hazard details, in particular characteristics of lunar surface dust, follows in Appendix A, and more detailed explanations of quantification issues for particulates are in Appendix B. The simple inertial removal of particles from a surface is discussed in Appendix C, followed by a summary of terrestrial best practices for dust mitigation recommended within select industries in Appendix D. The aggregated bibliography of references, while extensive and very useful, should not be construed to be exhaustive and can serve as a constructive start.

dust↗

NASA NTRS2013

Review of the Draft 2014 Science Mission Directorate Science Plan

At the request of NASA's Science Mission Directorate (SMD), the National Research Council's (NRC's) Space Studies Board (SSB) initiated a study to review a draft of the SMD's 2014 Science Plan. The request for this review was made at a time when NASA is engaged in the final stages of a comprehensive, agency-wide effort to develop a new strategic plan and at a time when NASA's budget is under considerable stress. SMD's Science Plan serves to provide more detail on its four traditional science disciplines-astronomy and astrophysics, solar and space physics (also called heliophysics), planetary science, and Earth remote sensing and related activities-than is possible in the agency-wide Strategic Plan. In conducting its review of the draft Science Plan, the Committee on the Assessment of the NASA Science Mission Directorate 2014 Science Plan was charged to comment on the following specific areas: (1) Responsiveness to the NRC's guidance on key science issues and opportunities in recent NRC reports; (2) Attention to interdisciplinary aspects and overall scientific balance; (3) Identification and exposition of important opportunities for partnerships as well as education and public outreach; (4) Integration of technology development with the science program; (5) Clarity on how the plan aligns with SMD's strategic planning process; (6) General readability and clarity of presentation; and (7) Other relevant issues as determined by the committee. The main body of the report provides detailed findings and recommendations relating to the draft Science Plan. The highest-level, crosscutting issues are summarized here, and more detail is available in the main body of the report.

Source record↗

NASA NTRS2009

Sensitive, Rapid Detection of Bacterial Spores

A method of sensitive detection of bacterial spores within delays of no more than a few hours has been developed to provide an alternative to a prior three-day NASA standard culture-based assay. A capability for relatively rapid detection of bacterial spores would be beneficial for many endeavors, a few examples being agriculture, medicine, public health, defense against biowarfare, water supply, sanitation, hygiene, and the food-packaging and medical-equipment industries. The method involves the use of a commercial rapid microbial detection system (RMDS) that utilizes a combination of membrane filtration, adenosine triphosphate (ATP) bioluminescence chemistry, and analysis of luminescence images detected by a charge-coupled-device camera. This RMDS has been demonstrated to be highly sensitive in enumerating microbes (it can detect as little as one colony-forming unit per sample) and has been found to yield data in excellent correlation with those of culture-based methods. What makes the present method necessary is that the specific RMDS and the original protocols for its use are not designed for discriminating between bacterial spores and other microbes. In this method, a heat-shock procedure is added prior to an incubation procedure that is specified in the original RMDS protocols. In this heat-shock procedure (which was also described in a prior NASA Tech Briefs article on enumerating sporeforming bacteria), a sample is exposed to a temperature of 80 C for 15 minutes. Spores can survive the heat shock, but nonspore- forming bacteria and spore-forming bacteria that are not in spore form cannot survive. Therefore, any colonies that grow during incubation after the heat shock are deemed to have originated as spores.

Kern, Roger G.↗

NASA NTRS2016

Post-Launch Calibration and Testing of Space Weather Instruments on GOES-R Satellite

The Geostationary Operational Environmental Satellite - R (GOES-R) is the first of a series of satellites to be launched, with the first launch scheduled for October 2016. The three instruments - Solar Ultra Violet Imager (SUVI), Extreme ultraviolet and X-ray Irradiance Sensor (EXIS), and Space Environment In-Situ Suite (SEISS) provide the data needed as inputs for the product updates National Oceanic and Atmospheric Administration (NOAA) provides to the public. SUVI is a full-disk extreme ultraviolet imager enabling Active Region characterization, filament eruption, and flare detection. EXIS provides inputs to solar backgrounds/events impacting climate models. SEISS provides particle measurements over a wide energy-and-flux range that varies by several orders of magnitude and these data enable updates to spacecraft charge models for electrostatic discharge. EXIS and SEISS have been tested and calibrated end-to-end in ground test facilities around the United States. Due to the complexity of the SUVI design, data from component tests were used in a model to predict on-orbit performance. The ground tests and model updates provided inputs for designing the on-orbit calibration tests. A series of such tests have been planned for the Post-Launch Testing (PLT) of each of these instruments, and specific parameters have been identified that will be updated in the Ground Processing Algorithms, on-orbit parameter tables, or both. Some of SUVI and EXIS calibrations require slewing them off the Sun, while no such maneuvers are needed for SEISS. After a six-month PLT period the GOES-R is expected to be operational. The calibration details are presented in this paper.

On-orbit Calibration↗

NASA NTRS2016

Post-Launch Calibration and Testing of Space Weather Instruments on GOES-R Satellite

The Geostationary Operational Environmental Satellite - R (GOES-R) is the first of a series of satellites to be launched, with the first launch scheduled for October 2016. The three instruments Solar UltraViolet Imager (SUVI), Extreme ultraviolet and X-ray Irradiance Sensor (EXIS), and Space Environment In-Situ Suite (SEISS) provide the data needed as inputs for the product updates National Oceanic and Atmospheric Administration (NOAA) provides to the public. SUVI is a full-disk extreme ultraviolet imager enabling Active Region characterization, filament eruption, and flare detection. EXIS provides inputs to solar back-ground-sevents impacting climate models. SEISS provides particle measurements over a wide energy-and-flux range that varies by several orders of magnitude and these data enable updates to spacecraft charge models for electrostatic discharge. EXIS and SEISS have been tested and calibrated end-to-end in ground test facilities around the United States. Due to the complexity of the SUVI design, data from component tests were used in a model to predict on-orbit performance. The ground tests and model updates provided inputs for designing the on-orbit calibration tests. A series of such tests have been planned for the Post-Launch Testing (PLT) of each of these instruments, and specific parameters have been identified that will be updated in the Ground Processing Algorithms, on-orbit parameter tables, or both. Some of SUVI and EXIS calibrations require slewing them off the Sun, while no such maneuvers are needed for SEISS. After a six-month PLT period the GOES-R is expected to be operational. The calibration details are presented in this paper.

On-orbit Calibration↗

NASA NTRS2002

Novel Advancements in Internet-Based Real Time Data Technologies

AZ Technology has been working with MSFC Ground Systems Department to find ways to make it easier for remote experimenters (RPI's) to monitor their International Space Station (ISS) payloads in real-time from anywhere using standard/familiar devices. AZ Technology was awarded an SBIR Phase I grant to research the technologies behind and advancements of distributing live ISS data across the Internet. That research resulted in a product called "EZStream" which is in use on several ISS-related projects. Although the initial implementation is geared toward ISS, the architecture and lessons learned are applicable to other space-related programs. This paper presents the high-level architecture and components that make up EZStream. A combination of commercial-off-the-shelf (COTS) and custom components were used and their interaction will be discussed. The server is powered by Apache's Jakarta-Tomcat web server/servlet engine. User accounts are maintained in a My SQL database. Both Tomcat and MySQL are Open Source products. When used for ISS, EZStream pulls the live data directly from NASA's Telescience Resource Kit (TReK) API. TReK parses the ISS data stream into individual measurement parameters and performs on-the- fly engineering unit conversion and range checking before passing the data to EZStream for distribution. TReK is provided by NASA at no charge to ISS experimenters. By using a combination of well established Open Source, NASA-supplied. and AZ Technology-developed components, operations using EZStream are robust and economical. Security over the Internet is a major concern on most space programs. This paper describes how EZStream provides for secure connection to and transmission of space- related data over the public Internet. Display pages that show sensitive data can be placed under access control by EZStream. Users are required to login before being allowed to pull up those web pages. To enhance security, the EZStream client/server data transmissions can be encrypted to preclude interception. EZStream was developed to make use of a host of standard platforms and protocols. Each are discussed in detail in this paper. The I3ZStream server is written as Java Servlets. This allows different platforms (i.e. Windows, Unix, Linux . Mac) to host the server portion. The EZStream client component is written in two different flavors: JavaBean and ActiveX. The JavaBean component is used to develop Java Applet displays. The ActiveX component is used for developing ActiveX-based displays. Remote user devices will be covered including web browsers on PC#s and scaled-down displays for PDA's and smart cell phones. As mentioned. the interaction between EZStream (web/data server) and TReK (data source) will be covered as related to ISS. EZStream is being enhanced to receive and parse binary data stream directly. This makes EZStream beneficial to both the ISS International Partners and non-NASA applications (i.e. factory floor monitoring). The options for developing client-side display web pages will be addressed along with the development of tools to allow creation of display web pages by non-programmers.

Myers, Gerry↗

NASA NTRS2017

Advanced Curation Activities at NASA: Preparation for Upcoming Missions

The responsibility for curating NASA's astromaterials collections falls to the NASA Curation Office at Johnson Space Center. Under the governing document, NASA Policy Directive (NPD) 7100.10F and derivative requirements documents, JSC is charged with curation of all extraterrestrial material under NASA control, including future NASA missions to include material returned in Mars Sample Return (MSR) efforts, OSIRIS-REx, NASA's subset of Hayabusa-2 samples, and any other sample return missions. The Directive defines Curation as activities including documentation, preservation, sample preparation, distribution, and tracking of samples for research, education, and public outreach. In this abstract we will describe Curation's research and development efforts to improve the care of existing collections and prepare for future NASA sample return missions. These efforts are collectively referred to as Advanced Curation, a term first coined in 2002.

Fries, M. D.↗

NASA NTRS2000

The ''Rock'': The Role of the Press in Bringing about Change in Aircraft Accident Policy

From 1926 to 1938, the Aeronautics Branch, forerunner of the Federal Aviation Administration (FAA), had been charged with aircraft accident investigation. While the Branch had been investigating accidents since its inception, it had, early in its tenure, put into place a policy making its findings secret. Media and political pressure began to mount in late 1928 over its policy of nondisclosure and the debate brought pressure to bear on the young Aeronautics Branch to reverse its policy and make its findings public. The focusing event for the Branch's policy reversal was the death of Knute Rockne, the famous Notre Dame football coach, in a Transcontinental and Western Airways (TWA) airliner on March 31, 193 1. This paper will examine the role of print media in bringing about a significant, and lasting, change in aircraft accident public-disclosure policy.

Johnson, Randy↗

NASA NTRS2012

The NASA Human Research Wiki - An Online Collaboration Tool

The Exploration Medical Capability (ExMC) element is one of six elements of the Human Research Program (HRP). ExMC is charged with decreasing the risk of: "Inability to adequately recognize or treat an ill or injured crew member" for exploration-class missions In preparation for exploration-class missions, ExMC has compiled a large evidence base, previously available only to persons within the NASA community. ExMC has developed the "NASA Human Research Wiki" in an effort to make the ExMC information available to the general public and increase collaboration within and outside of NASA. The ExMC evidence base is comprised of several types of data, including: (1)Information on more than 80 medical conditions which could occur during space flight (a)Derived from several sources (b)Including data on incidence and potential outcomes, as captured in the Integrated Medical Model s (IMM) Clinical Finding Forms (CliFFs). (2)Approximately 25 gap reports (a)Identify any "gaps" in knowledge and/or technology that would need to be addressed in order to provide adequate medical support for these novel missions.

Barr, Yael↗

NASA NTRS2015

When the Sky Falls NASA's Response to Bright Bolide Events Over Continental USA

Being the only U.S. Government entity charged with monitoring the meteor environment, the Meteoroid Environment Office (MEO) has deployed a network of allsky and wide field meteor cameras, along with the appropriate software tools to quickly analyze data from these systems. However, the coverage of this network is still quite limited, forcing the incorporation of data from other cameras posted to the internet in analyzing many of the fireballs reported by the public and media. Information on these bright events often needs to be reported to NASA Headquarters by noon the following day; thus a procedure has been developed that determines the analysis process for a given fireball event based on the types and amount of data available. The differences between these analysis processes are shown by looking at four meteor events that the MEO responded to, all of which were large enough to produce meteorites.

Blaauw, R. C.↗

NASA NTRS2015

NASA's Meteoroid Environments Office's Response to Three Significant Bolide Events Over North America

Being the only U.S. Government entity charged with monitoring the meteor environment, the Meteoroid Environment Office has deployed a network of all sky and wide field meteor cameras, along with the appropriate software tools to quickly analyze data from these systems. However, the coverage of this network is still quite limited, forcing the incorporation of data from other cameras posted to the internet in analyzing many of the fireballs reported by the public and media. A procedure has been developed that determines the analysis process for a given fireball event based on the types and amount of data available. The differences between these analysis process will be explained and outlined by looking at three bolide events, all of which were large enough to produce meteorites. The first example is an ideal event - a bright meteor that occurred over NASA's All Sky Camera Network on August 2, 2014. With clear video of the event from various angles, a high-accuracy trajectory, beginning and end heights, orbit and approximate brightness/size of the event are able to be found very quickly using custom software. The bolide had the potential to have dropped meteorites, so dark flight analysis and modeling was performed, allowing potential fall locations to be mapped as a function of meteorite mass. The second case study was a bright bolide that occurred November 3, 2014 over West Virginia. This was just north of the NASA southeastern all-sky network, and just south of the Ohio-Pennsylvania network. This case study showcases the MEO's ability to use social media and various internet sources to locate videos of the event from obscure sources (including the Washington Monument) for anything that will permit a determination of a basic trajectory and fireball light curve The third case study will highlight the ability to use doppler weather radar in helping locate meteorites, which enable a definitive classification of the impactor. The input data and analysis steps differ for each case study, but the goals remain the same - a trajectory, orbit, and mass estimate for the bolide within hours of the event, and, for events with a high probability of producing meteorites, a location of the strewn field within a day.

Blaauw, Rhiannon C.↗

NASA NTRS2004

Removing Spectral Diagnostics of Galactic and Stellar X-Ray Emission from Charged Exchange Recombination

Our research uses the electron beam ion trap (EBIT) at the Lawrence Livermore National Laboratory to study X-ray emission from the charge exchange (CX) of highly charged ions with neutral gases. The resulting data help to fill a void in existing experimental and theoretical understanding of this atomic physics process, and are needed to explain all or part of the observed X-ray emission from the soft X-ray background, stellar winds, the Galactic Center and Galactic Ridge, supernova ejecta, and photoionized nebulae. Appreciation of the astrophysical relevance of our work continues to grow with the publication of roughly a dozen papers in the past four years describing Chandra and XMM observations of geocoronal and heliospheric CX emission, the temporal variation of such emission and correlation with X-ray emission enhancements observed by ROSAT, the theoretical spatial distribution of that emission, and CX emission around other stars. A similar number of papers were also published during that time describing CX emission from planets and comets. We expect that the launch of ASTRSE2, with its second-generation XRS microcalo- (with 6-eV resolution), will reveal even more clearly the contributions of CX to astrophysical emission. In our EBIT work we collected CX spectra from such ions as H-like and He-like Ne, Ar, and Fe. Our early measurements were made with a high-purity Ge detector, but during the second year we began operation of the first-generation XRS microcalorimeter (a twin of the XRS on ASTRO-E) and greatly improved the resolution of our measurements from roughly 150 eV (FWHM) with the Ge detectors to 10 eV with the XRS. We found that saturation of the XRS counting apparatus, which we described in our proposal as a potential concern, is not a problem for studying CX. During the course of our research, we expanded the number of injection gases permitted by the LLNL safety team, purchased and eventually operated an atomic H source, and clearly demonstrated the feasibility of our longer-range plan. For example, we successfully injected He into EBIT (not a small feat because of the difficulty of maintaining a good vacuum with He and avoiding electrical breakdown) to collect a H-like oxygen CX spectrum. The highest energy CX spectrum recorded with the XRS to date is that of the Ar K-shell emission. These measurements provided the first observation of the relative intensity ratios of resolved He-like singlet and triplet n=2->1 lines. We also carried out measurements of He-like Ne as a function of collision energy (i.e., ion temperature). Significant differences in the resulting x-ray spectra were noted. In all cases, the intensity of high-n H-like Lyman lines is significantly higher than current theoretical CX models predict.

Wargelin, Brad↗

NASA NTRS2017

Spacecraft and Instrument Photoelectrons Measured by the Dual Electron Spectrometers on MMS

Secondary electrons are continuously generated via photoemission from sunlit spacecraft and instrument surfaces. These particles can subsequently contaminate low-energy channels of electron sensors. Spacecraft photoelectrons are measured at energies below that of a positive spacecraft potential and can be removed at the expense of energy resolution. However, fluxes of photoelectrons generated inside electron instruments are independent of spacecraft potential and must be fully characterized in order to correct electron data. Here we present observations of spacecraft and instrument photoelectron populations measured with the Dual Electron Spectrometers (DES) on NASA's Magnetospheric Multiscale (MMS) mission. We leverage observations from Earth's nightside plasma sheet taken during MMS commissioning and develop an empirical model of instrument photoelectrons. This model is used with DES velocity distribution functions to correct plasma moments and has been made publicly available on the MMS science data center for use by the scientific community.

photoelectrons↗

NASA NTRS1974

Charged Particle lunar Environment Experiment (CPLEE)

Research development in the Charged Particle Lunar Environment Experiment (CPLEE) is reported. The CPLEE is ion-electron spectrometer placed on the lunar surface for the purpose of measuring charged particle fluxes impacting the moon from a variety of regions and to study the interactions between space plasmas and the lunar surface. The principal accomplishments reported include: (1) furnishing design specifications for construction of the CPLEE instruments; (2) development of an advanced computer-controlled facility for automated instrument calibration; (3) active participation in the deployment and past-deployment operational phases with regard to data verification and operational mode selection; and (4) publication of research papers, including a study of lunar photoelectrons, a study of plasmas resulting from man-made lunar impart events, a study of magnetotail and magnetosheath particle populations, and a study of solar-flare interplanetary particles.

Reasoner, D. L.↗

NASA NTRS1998

X-Ray Diffraction Analysis of NLO Crystals: Traditional Applications and More New Opportunities

Single crystal X-ray diffraction analysis is one of the more important methods for the molecular and crystal structure determination of matter and therefore it has a great importance in material science including design and engineering of different compounds with non-linear optical (NLO) properties. It was shown in our previous publications that this method provides unique information about molecular structure of NLO compounds, their crystal symmetry and crystal packing arrays, molecular conformation and geometries and many other structural and electronic characteristics that are important for understanding the nature of NLO properties of solids. A very new application of the X-ray diffraction method is related to analysis of the electron density distribution p(r) in crystals and some of its characteristics (atomic and group charges, dipole and higher multipole moments, etc.), that may be obtained directly form the diffraction measurements. In the present work, we will discuss our preliminary low temperature high-resolution X-ray data for the m-nitroaniline (mNA) single crystal (VI). This is one of the "classical" organic NLO materials and electron density distribution analysis in this simple compound has a great scientific interest.

Antipin, Mikhail Yu.↗

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 six-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.↗