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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 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Simulated traveling interplanetary disturbances initiated by various solar phenomena

Earlier studies have shown that interplanetary disturbances observed by spacecraft at large heliocentric distances from the sun can be directly associated with various solar activities such as surges, sprays, eruptive prominences, and flares. A digital computer code to simulate these phenomena is developed. This numerical code solves a set of conservation equations for an adiabatic time-dependent spherically-symmetric fluid flow. The solar events are simulated by perturbations in the dependent variables at the lower boundary of the quiet sun corona, and the time-dependent numerical solution simulates the coronal response. Three physical cases are simulated by using the proposed numerical code: (1) part of a surge, spray and prominence; (2) a single flare; and (3) two flares whose interplanetary consequences interact in space. Results for the first two cases are compared with both ground-based and space probe observations. Fairly good agreement with observations is found. A comparison of the third case with observations is presently under way.

Dryer, M.↗
NASA NTRS1979

Galileo to Jupiter: Probing the Planet and Mapping Its Moons

The first project to use the space shuttle as an interplanetary launch vehicle, the Galileo mission is designed to obtain information about the origin and evolution of the solar system by studying large-scale phenomena on Jupiter and its satellites. Aimed towards Mars to obtain gravity assist, the orbiting spacecraft will deploy a probe, which penetrating the Jovian atmosphere, will transmit data for approximately an hour. The spacecraft itself will inspect the atmospheres, ionospheres, and surfaces of Ganymede, Io, Europa, and Callisto, as well as determine their magnetic and gravitational properties. The experiments to be conducted and their scientific objectives are described. Known facts about the Jovian system are reviewed.

Source record↗
NASA NTRS1984

Extended mission life support systems

The life support systems employed in manned space missions have generally been based on the use of expendables, such as, for instance, liquid oxygen. For the conducted space missions, such systems have advantages related to volume, weight, and economy of power consumption. However, this situation will change in connection with Shuttle Orbiter missions of extended duration, permanent manned facilities in low-earth orbit, and ultimately manned planetary vehicles. A description is given of suitable regenerative life support systems for such extended manned space missions. Attention is given to advanced life support systems technology, air revitalization, CO2 reduction, oxygen generation, nitrogen generation, trace contaminant control, air revitalization system integration, control/monitor instrumentation, water reclamation, solid waste management, manned testing and life support integration, an enhanced duration orbiter, a space operations center, manned interplanetary life support systems, and future development requirements.

Quattrone, P. D.↗
NASA NTRS1990

Radiological health risks to astronauts from space activities and medical procedures

Radiation protection standards for space activities differ substantially from those applied to terrestrial working situations. The levels of radiation and subsequent hazards to which space workers are exposed are quite unlike anything found on Earth. The new more highly refined system of risk management involves assessing the risk to each space worker from all sources of radiation (occupational and non-occupational) at the organ level. The risk coefficients were applied to previous space and medical exposures (diagnostic x ray and nuclear medicine procedures) in order to estimate the radiation-induced lifetime cancer incidence and mortality risk. At present, the risk from medical procedures when compared to space activities is 14 times higher for cancer incidence and 13 times higher for cancer mortality; however, this will change as the per capita dose during Space Station Freedom and interplanetary missions increases and more is known about the risks from exposure to high-LET radiation.

Peterson, Leif E.↗
NASA NTRS1994

The causes of geomagnetic storms during solar maximum

One of the oldest mysteries in geomagnetism is the linkage between solar and geomagnetic activity. In investigating the causes of geomagnetic storms occurring during solar maximum, the following topics are discussed: solar phenomena; types of solar wind; magnetic reconnection and magnetic storms; an interplanetary example; and future space physics missions.

Tsurutani, Bruce T.↗
NASA NTRS2006

Immune Response in Microgravity: Genetic Basis and Countermeasure Development Implications

Impairment of the immunity in astronauts and cosmonauts even in shortterm flights is a recognized risk. Longterm orbital space missions and anticipated interplanetary flights increase the concern for more pronounced effects on the immune system with potential clinical consequences. Studies in true and modeled microgravity (MG) have demonstrated that MG directly affects numerous lymphocyte functions. The purpose of this study was to screen for genes involved in lymphocytes response to modeled microgravity (MMG) that could explain the functional and structural changes observed earlier. The microgravity-induced changes in gene expression were analyzed by microarray DNA chip technology. CD3and IL2activated Tcells were cultured in 1g (static) and modeled microgravity (NASA Rotating Wall Vessel bioreactor) conditions for 24 hours. Total RNA was extracted using the RNeasy isolation kit (Qiagen, Valencia, CA). Microarray experiments were performed utilizing Affymetrix Gene Chips (U133A), allowing testing for 18,400 human genes. To decrease the biological variation and aid in detecting microgravity-associated changes, experiments were performed in triplicate using cells obtained from three different donors. Exposure to modeled microgravity resulted in alteration of 89 genes, 10 of which were upregulated and 79 down-regulated. Altered genes were categorized by their function, structural role and by association with metabolic and regulatory pathways. A large proportion was found to be involved in fundamental cellular processes: signal transduction, DNA repair, apoptosis, and multiple metabolic pathways. There was a group of genes directly related to immune and inflammatory responses (IL7R, granulysin, proteasome activator subunit 2, peroxiredoxin 4, HLADRA, lymphocyte antigen 75, IL18R and DOCK2 genes). Among these genes only one (IL7R) was upregulated, the rest were downregulated. The upregulation of the IL7 receptor gene was confirmed by RT PCR. Three genes with altered expression were identified in the apoptosis related group (Granzyme B, APO2 ligand and Beta3endonexin). All of them were downregulated. Gene expression changes in MG might appear pivotal in identifying potential molecular targets for countermeasure development. (Supported by NRA OLMSA02 and NSCORT NAG54072 grants).

Risin, Diana↗
NASA NTRS2006

DSMS Services and Capabilities

This viewgraph presentation reviews Interplanetary Network Directorate Deep Space Mission Systems services and support capabilities. The contents include: 1) Organization Chart; 2) IND DSMS Support Facilities; 3) Standard Services; and 4) Support Capabilities including Telemetry, command and tracking.

communications↗
NASA NTRS2009

Ultra-Large Solar Sail

UltraSail is a next-generation ultra-large (km2 class) sail system. Analysis of the launch, deployment, stabilization, and control of these sails shows that high-payload-mass fractions for interplanetary and deep-space missions are possible. UltraSail combines propulsion and control systems developed for formation-flying microsatellites with a solar sail architecture to achieve controllable sail areas approaching 1 km2. Electrically conductive CP-1 polyimide film results in sail subsystem area densities as low as 5 g/m2. UltraSail produces thrust levels many times those of ion thrusters used for comparable deep-space missions. The primary innovation involves the near-elimination of sail-supporting structures by attaching each blade tip to a formation- flying microsatellite, which deploys the sail and then articulates the sail to provide attitude control, including spin stabilization and precession of the spin axis. These microsatellite tips are controlled by microthrusters for sail-film deployment and mission operations. UltraSail also avoids the problems inherent in folded sail film, namely stressing, yielding, or perforating, by storing the film in a roll for launch and deployment. A 5-km long by 2 micrometer thick film roll on a mandrel with a 1 m circumference (32 cm diameter) has a stored thickness of 5 cm. A 5 m-long mandrel can store a film area of 25,000 m2, and a four-blade system has an area of 0.1 sq km.

Burton, Rodney↗
NASA NTRS2011

Space Environmental Erosion of Polar Icy Regolith

While regions at the floors of permanently shadowed polar craters are isolated from direct sunlight, these regions are still exposed to the harsh space environment, including the interplanetary Lyman-a background, meteoric impacts, and obstacle-affected solar wind. We demonstrate that each of these processes can act to erode the polar icy regolith located at or near the surface along the crater floor. The Lyman-a background can remove/erode the icy-regolith via photon stimulated desorption [1], meteoric impacts can vaporize the regolith [2], and redirected solar wind ions can sputter the ice-regolith mix [3]. As an example we shall examine in detail the inflow of solar wind ions and electrons into polar craters, One might expect such ions to flow horizontally over the crater top (see Figure). However, we find that plasma ambipolar processes act to deflect passing ions into the craters [3]. We examine this plasma process and determine the ion flux as a function of position across a notional crater floor. We demonstrate that inflowing solar wind ions can indeed create sputtering along the crater floor, effectively eroding the surface. Erosion time scales rrom sputtering will be presented. We shall also consider the effect of impact vaporization on buried icy-regolith regions. There will also be a discussion of solar wind electrons that enter into the PSR, demonstrating that these also have the ability rree surface-bound atoms via electron stimulated desorption processes [l].

Farrell, William M.↗
NASA NTRS2008

Evolutionary Paths to Internationally-Standardized Space Internetworking

The space community is now poised at the start of an exciting new era of space exploration, where many different organization will be launching spacecraft to investigate nearby bodies, such as the Moon and Mars. International fleets of spacecraft are thus likely to begin to fly and interoperability will often become a mission-enabling technology. These fleets will require a mix of powerful data communications capabilities to be available, ranging from conventional point-to-point architectures to new configurations supporting internetworked operations. This paper reviews the various CCSDS capabilities to support fully-standardized in-space internetworking, and outlines a strategy for smoothly evolving into the new era with minimum impact on the highly successful installed base of CCSDS-compatible systems, which are now widely deployed across the international space community.

Space Internet↗
NASA NTRS2017

Fluid Transient Analysis During Priming of Evacuated Line

Pressure surges are critical in the design of spacecraft propellant feed lines. The pressure transients that occur during priming of feed lines are very important in the design and analysis of liquid propulsion systems. During the start-up of the propulsion system of a spacecraft, the process of filling of an evacuated pipeline is called priming. Priming can generate severe pressure peaks due to the slam (water hammer) of the propellant against a closed thruster valve. The downstream conditions strongly affect the pressure surge. In space systems, satellites, or interplanetary probes, the propellant lines are vacuum-pumped or filled with low pressure helium or nitrogen before the launch. Before operations, these lines are primed with a vaporizing liquid, sometimes in the presence of a non-condensable gas (NCG), which produces water hammer phenomena. The objective of the current study is to use a finite volume based network flow solver (Generalized Fluid System Simulation Program, GFSSP) for the numerical simulation of Priming in (a) a straight feedline and (b) a flow network. The geometrical configurations and dimensions for the pipe and other components used for the current study are identical to experimental study of Prickett et al.

Bandyopadhyay, Alak↗
NASA NTRS2018

Forecasting the Arrival Time of Coronal Mass Ejections: Analysis of the CCMC CME Scoreboard

Accurate forecasting of the properties of coronal mass ejections (CMEs) as they approach Earth is now recognized as an important strategic objective for both NOAA and NASA. The time of arrival of such events is a key parameter, one that had been anticipated to be relatively straightforward to constrain. In this study, we analyze forecasts submitted to the Community Coordinated Modeling Center at NASA's Goddard Space Flight Center over the last 6 years to answer the following questions: (1) How well do these models forecast the arrival time of CME-driven shocks? (2) What are the uncertainties associated with these forecasts? (3) Which model(s) perform best? (4) Have the models become more accurate during the past 6 years? We analyze all forecasts made by 32 models from 2013 through mid-2018, and additionally focus on 28 events, all of which were forecasted by six models. We find that the models are generally able to predict CME-shock arrival times, in an average sense, to within ±10 hr, but with standard deviations often exceeding 20 hr. The best performers, on the other hand, maintained a mean error (bias) of 1 hr, a mean absolute error of 13 hr, and a precision (standard deviation) of 15 hr. Finally, there is no evidence that the forecasts have become more accurate during this interval. We discuss the intrinsic simplifications of thevarious models analyzed, the limitations of this investigation, and suggest possible paths to improve these forecasts in the future.

space weather↗
NASA NTRSDate not supplied

Space Communications in Support of the Artemis Program

NASA has been challenged to send the first woman and first person of color to the South Pole of the moon by 2024. Named the Artemis Program, this effort serves as a proving ground for the greater Moon-to-Mars campaign and establishes a lunar outpost by 2028. The Artemis Program relies on simultaneous operation of multiple flight assets separated by large angular distances that require a unique communication strategy and is a departure from the previous Apollo-era architecture. NASA’s Space Communications and Navigation (SCaN) Program is designing a scalable, extensible, and reusable network architecture to provide communication and navigation services in support of lunar exploration. This architecture serves at the foundational infrastructure, paving the way for future exploration of Mars. In pursuance of this new architecture, the SCaN Program is augmenting NASA’s space communications networks by upgrading the current 34-meter beam waveguide antenna systems and incorporating an 18-meter class subnet. This paper presents an overview of NASA’s plans to provide high data rate communication and navigation services for lunar exploration efforts including: operations concepts to support the lunar communications architecture, major network enhancements and new capabilities, and a Mars-forward approach that maximizes the reuse of these capabilities. Capabilities include:(1) Delay/Disruption Tolerant Networking (DTN), (2) Multiple Spacecraft Per Aperture (MSPA, also known as Multiple Spacecraft Per Antenna), and (3) Simultaneous Ka-band uplink and downlink. The mid-2020s era is a historic opportunity to advance NASA’s space communications infrastructure as humans return to the moon and continue to interplanetary exploration, starting with Mars. The space communication infrastructure is a lifeline that supports these endeavors, furthering humankinds’ exploration and understanding of the universe.

Philip A Baldwin↗
NASA NTRS2024

Anisotropy of Density Fluctuations in the Solar Wind at 1 au

A well-known property of solar wind plasma turbulence is the observed anisotropy of the autocorrelations, or equivalently the spectra, of velocity and magnetic field fluctuations. Here we explore the related but apparently not well-studied issue of the anisotropy of plasma density fluctuations in the energy-containing and inertial ranges of solar wind turbulence. Using 10 yr (1998–2008) of in situ data from the Advanced Composition Explorer mission, we find that for all but the fastest wind category, the density correlation scale is slightly larger in directions quasi-parallel to the large-scale mean magnetic field as compared to quasi-perpendicular directions. The correlation scale in fast wind is consistent with isotropic. The anisotropy as a function of the level of correlation is also explored. We find at small correlation levels, i.e., at energy-containing scales and larger, the density fluctuations are close to isotropy for fast wind, and slightly favor more rapid decorrelation in perpendicular directions for slow and medium winds. At relatively smaller (inertial range) scales where the correlation values are larger, the sense of anisotropy is reversed in all speed ranges, implying a more "slablike" structure, especially prominent in the fast wind samples. We contrast this finding with published results on velocity and magnetic field correlations.

Interplanetary turbulence↗
NASA NTRS2020

Autonomous Optical-only Navigation for Deep Space Missions

Navigation of spacecraft for interplanetary missions is typically performed on the ground using a two-way radio link to obtain the necessary tracking data. Due to the limited number of antenna capable of tracking these spacecraft, it would be advantageous to have a navigation capability that is entirely self-contained onboard a spacecraft. A camera mounted on a spacecraft is theoretically capable of enabling self-navigating spacecraft, and has been demonstrated in limited circumstances in past missions. Fundamentally, the technique involves using various natural or artificial targets as observational beacons to determine the observers position in space. In this paper, the technique of optical-only navigation is described, including discussions of what types of observations are used, and results of analysis showing the accuracies achievable for various mission types across the Solar System is discussed.

Bhaskaran, Shyam↗
NASA NTRS1993

Conceptual communications system design in the 25.25-27.5 and 37.0-40.5 GHz frequency bands

Future space applications are likely to rely heavily on Ka-band frequencies (20-40 GHz) for communications traffic. Many space research activities are now conducted using S-band and X-band frequencies, which are becoming congested and require a degree of pre-coordination. In addition to providing relief from frequency congestion, Ka-band technologies offer potential size, weight, and power savings when compared to lower frequency bands. The use of the 37.0-37.5 and 40.0-40.5 GHz bands for future planetary missions was recently approved at the 1992 World Administrative Radio Conference (WARC-92). WARC-92 also allocated the band 25.25-27.5 GHz to the Intersatellite Service on a primary basis to accommodate Data Relay Satellite return link requirements. Intersatellite links are defined to be between artificial satellites and thus a communication link with the surface of a planetary body, such as the moon, and a relay satellite orbiting that body are not permitted in this frequency band. This report provides information about preliminary communications system concepts for forward and return links for earth-Mars and earth-lunar links using the 37.0-37.5 (return link) and 40.0-40.5 (forward link) GHz frequency bands. In this study we concentrate primarily on a conceptual system for communications between earth and a single lunar surface terminal (LST), and between earth and a single Mars surface terminal (MST). Due to large space losses, these links have the most stringent link requirements for an overall interplanetary system. The earth ground station is assumed to be the Deep Space Network (DSN) using either 34 meter or 70 meter antennas. We also develop preliminary communications concepts for a space-to-space system operating at near 26 GHz. Space-to-space applications can encompass a variety of operating conditions, and we consider several 'typical' scenarios described in more detail later in this report. Among these scenarios are vehicle-to-vehicle communications, vehicle-to-geosyncronous satellite (GEO) communications, and GEO-to-GEO communications. Additional details about both the interplanetary and space-to-space communications systems are provided in an 'expanded' final report which has been submitted to the Tracking and Communications Division (TCD) at the NASA Johnson Space Center.

Thompson, Michael W.↗
NASA NTRS1972

The interplanetary pioneers. Volume 1: Summary

The Pioneer Space Probe Project is explained to document the events which occurred during the project. The subjects discussed are: (1) origin and history of interplanetary Pioneer program, (2) Pioneer system development and design, (3) Pioneer flight operations, and (4) Pioneer scientific results. Line drawings, circuit diagrams, illustrations, and photographs are included to augment the written material.

Corliss, W. R.↗