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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 685 records · Page 38

All sources NASA NTRS DOE OSTI

NASA NTRS1998

Verification and Quantification of Single Event Effects on High Speed SRAM in Terrestrial Environments

As integrated circuits become more sensitive to charged particles and neutrons, anomalous performance due to single event effects (SEE) is a concern and requires experimental verification and quantification. The Center for Applied Radiation Research (CARR) at Prairie View A&M University has developed experiments as a participant in the NASA ER-2 Flight Program, the APEX balloon flight program and the Student Launch Program. Other high altitude and ground level experiments of interest to DoD and commercial applications are being developed. The experiment characterizes the SEE behavior of high speed and high density SRAM's. The system includes a PC-104 computer unit, an optical drive for storage, a test board with the components under test, and a latchup detection and reset unit. The test program will continuously monitor the stored checkerboard data pattern in the SW and record errors. Since both the computer and the optical drive contain integrated circuits, they are also vulnerable to radiation effects. A latchup detection unit with discrete components will monitor the test program and reset the system when necessary. The first results will be obtained from the NASA ER-2 flights, which are now planned to take place in early 1998 from Dryden Research Center in California. The series of flights, at altitudes up to 70,000 feet, and a variety of flight profiles should yield a distribution of conditions for correlating SEES. SEE measurements will be performed from the time of aircraft power-up on the ground throughout the flight regime until systems power-off after landing.

Huff, H.↗

NASA NTRS1999

JPL Institutional Parts Program

This viewgraph presentation focuses on the past, present, and future space parts environment. The past environment was characterized by long lead time flagship missions having substantial support from NASA and DOD. The future environment is characterized by many BFC missions, short development cycles, smaller projects and shorter part delivery schedules. These ideas are elaborated upon.

Clark, Kevin P.↗

NASA NTRS2000

Alkyl Pyrocarbonate Electrolyte Additives for Performance Enhancement of Li Ion Cells

Lithium ion rechargeable batteries are being developed for various aerospace applications under a NASA-DoD Interagency program. These applications require further improvements in several areas, specifically in the cycle life for LEO and GEO satellites and in the low temperature performance for the Mars Lander and Rover missions. Accordingly, we have been pursuing research studies to achieve improvement in the low temperature performance, long cycle life and active life of Li ion cells. The studies are mainly focused on electrolytes, to identify newer formulations of new electrolyte additives to enhance Li permeability (at low temperatures) and stability towards the electrode. The latter approach is particularly aimed at the formation suitable SEI (solid electrolyte interphase) on carbon electrodes. In this paper, we report the beneficial effect of using alkyl pyrocarbonates as electrolyte additives to improve the low temperature performance of Li ion cells.

Smart, M. C.↗

NASA NTRS2000

Integrated Circuit Immunity

This paper presents a DOD E3 program overview on integrated circuit immunity. The topics include: 1) EMI Immunity Testing; 2) Threshold Definition; 3) Bias Tee Function; 4) Bias Tee Calibration Set-Up; 5) EDM Test Figure; 6) EMI Immunity Levels; 7) NAND vs. and Gate Immunity; 8) TTL vs. LS Immunity Levels; 9) TP vs. OC Immunity Levels; 10) 7805 Volt Reg Immunity; and 11) Seventies Chip Set. This paper is presented in viewgraph form.

Sketoe, J. G.↗

NASA NTRS2000

Preliminary Analysis and Design of a Rocket Based Combined Cycle for Efficient Access to Space

Access to space is presently limited by cost. The cost of delivering a payload to low earth orbit (LEO) is on average $10,000 per pound of payload, in the United States. Much of this cost is incurred from the operation of vehicles developed with 30-40 year old technology. The old technology and design practices have resulted in expensive hardware and intensive maintenance requirements for current launch vehicles. In order to alleviate the cost factor, the technological advances throughout the next millennium must bring affordable development and a new invigorating desire to space exploration. National Aeronautical and Space Administration (NASA), Department of Defense (DOD), and private industry are addressing this issue by focusing on incremental improvements in the Earth- to Orbit (ETO) costs. These improvements have investigated two different approaches: 1) make space vehicles as inexpensive as possible (i.e. Evolved Expendable Launch Vehicle (EELV) and Delta IV) 2) make space vehicles as reusable as airplanes so that the initial cost of investment can be recaptured (i.e. Reusable Launch Vehicle (RLV), X-33, X-34, and X-37) These programs have made notable progress in new material, propulsion, structures, and avionics technologies, during the last 3-5 years. So far, these programs are targeted to reduce present costs by, as much as, five times the current cost. The year 2025 goal for continued space advancement is to have ETO costs reduced by a factor of ten (i.e., tenfold), as low as $100 - $200/lb payload. For the RLV, this goal translates into very low maintenance costs and higher expected reliability per flight must be obtained. Therefore, making higher launch rates possible. For the expendable vehicle, the cost of maintenance cost is minimal, but a greater reliability must exist to insure the payload; since, there would be no way to recover the payload if the mission was to an abort or failure. Overall the cost of vehicle, payload and operations of an expendable may be too high compared to those of the RLV.

Harris, Lawanna↗

NASA NTRS1999

Recent Measurements of the Orbital Debris Environment at NASA Johnson Space Center

Space debris presents many challenges to current space operations. Although, the probability of collision between an operational spacecraft and a piece of space debris is quite small, the potential losses can be quite high. Prior to 1990, characterization of the orbital debris environment was divided into two categories. Objects larger than 10 cm are monitored by the United States Space Surveillance Network (SSN) and documented in the U.S. Space Command (USSPACECOM) catalog. Knowledge of debris smaller than 0.1 cm has come from the analyses of returned surfaces. The lack of information about the debris environment in the size range from 0.1 to 1 0 cm led to a joint NASA-DOD effort for orbital debris measurements using the Haystack radar and the unbuilt Haystack Auxiliary (HAX) radars. The data from these radars have been critical to the design of shielding for the International Space Station and have been extensively used in the creation of recent models describing the orbital debris environment. Recent debris campaigns have been conducted to verify and validate through comparative measurements, the results and conclusions drawn from the Haystack/HAX measurements. The Haystack/HAX measurements and results will be described as well as the results of the recent measurement campaigns.

Stansbery, E. G.↗

NASA NTRS2000

Internet Technology on Spacecraft

The Operating Missions as Nodes on the Internet (OMNI) project has shown that Internet technology works in space missions through a demonstration using the UoSAT-12 spacecraft. An Internet Protocol (IP) stack was installed on the orbiting UoSAT-12 spacecraft and tests were run to demonstrate Internet connectivity and measure performance. This also forms the basis for demonstrating subsequent scenarios. This approach provides capabilities heretofore either too expensive or simply not feasible such as reconfiguration on orbit. The OMNI project recognized the need to reduce the risk perceived by mission managers and did this with a multi-phase strategy. In the initial phase, the concepts were implemented in a prototype system that includes space similar components communicating over the TDRS (space network) and the terrestrial Internet. The demonstration system includes a simulated spacecraft with sample instruments. Over 25 demonstrations have been given to mission and project managers, National Aeronautics and Space Administration (NASA), Department of Defense (DoD), contractor technologists and other decisions makers, This initial phase reached a high point with an OMNI demonstration given from a booth at the Johnson Space Center (JSC) Inspection Day 99 exhibition. The proof to mission managers is provided during this second phase with year 2000 accomplishments: testing the use of Internet technologies onboard an actual spacecraft. This was done with a series of tests performed using the UoSAT-12 spacecraft. This spacecraft was reconfigured on orbit at very low cost. The total period between concept and the first tests was only 6 months! On board software was modified to add an IP stack to support basic IP communications. Also added was support for ping, traceroute and network timing protocol (NTP) tests. These tests show that basic Internet functionality can be used onboard spacecraft. The performance of data was measured to show no degradation from current approaches. The cost to implement is much less than current approaches due to the availability of highly reliable and standard Internet tools. Use of standard Internet applications onboard reduces the risk of obsolescence inherent in custom protocols due to extremely wide use across all domains. These basic building blocks provide the framework for building onboard software to support direct user communication with payloads including payload control. Other benefits are payload to payload communication from dissimilar spacecraft, constellations of spacecraft, and reconfigurability on orbit. This work is funded through contract with the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC).

Rash, James↗

NASA NTRS2000

Performance Characteristics of Lithium Ion Prototype Cells for 2003 Mars Sample Return Athena Rover

A viewgraph presentation outlines the mission objectives and power subsystem for the Mars Sample Return (MSR) Athena Rover. The NASA-DOD (depth of discharge) Interagency Li Ion program objectives are discussed. Evaluation tests performed at JPL are listed, and test results are shown for the Li-Ion cell initial capacity, charge/discharge capacity, voltage and ratio, specific energy, watt-hour efficiency, and cell voltage at various temperatures.

Ratnakumar, B. V.↗

NASA NTRS2000

Empirical Approaches to Motor Stability Problems

Combustion stability remains a technical issue in some solid rocket motor development programs because techniques to characterize propellant and motor during a development program either do not exist or are inadequate. Moreover, the situation will remain uncertain until one or more stability related diagnostics that are routine, inexpensive, introduce no risk, and 'industrial strength' are qualified and accepted by the Department of Defense (DoD) and commercial customers. This paper describes an empirical diagnostic technique--passive motor diagnostics--with this potential and illustrates some of its characteristics. This methodology will provide customers with a level of confidence, after early development firing, that does not exist today.

Hessler, R. O.↗

NASA NTRS2000

1999 NASA Seal/Secondary Air System Workshop

NASA Glenn hosted the Seals/Secondary Air System Workshop on October 2829, 1999. Each year NASA and our industry and university partners share their respective seal technology development. We use these workshops as a technical forum to exchange recent advancements and "lessons-learned" in advancing seal technology and solving problems of common interest. As in the past we are publishing two volumes. Volume 1 will be publicly available and will be made available on-line through the web page address listed at the end of this chapter. Volume 2 will be restricted under International Traffic and Arms Regulations (I.T.A.R.) In this conference participants gained an appreciation of NASA's new Ultra Efficient Engine Technology (UEET) program and how this program will be partnering with ongoing DOE -industrial power production and DOD- military aircraft engine programs. In addition to gaining a deeper understanding into sealing advancements and challenges that lie ahead, participants gained new working and personal relationships with the attendees. When the seals and secondary fluid management program was initiated, the emphasis was on rocket engines with spinoffs to gas turbines. Today, the opposite is true and we are, again building our involvement in the rocket engine and space vehicle demonstration programs.

Steinetz, Bruce M.↗

NASA NTRS2001

Mirror Technology Development at MSFC for the Next Generation Space Telescope and Other Space Telescope Missions

Large-aperture low-areal-density mirrors are critical to the success of the Next Generation Space Telescope (NGST) as well as other related space missions such as the Space Based Laser (SBL). Currently fabrication technology has demonstrated areal densities of 50 kg/sq m. NASA and its DOD partners are conducting a series of risk reduction projects to demonstrate mirror fabrication technology for mirror systems with areal densities of 15 kg/sq m. This talk will present an overview of these risk reduction experiments.

Stahl, H. Philip↗

NASA NTRS2001

Status of Pulsed Inductive Thruster Research

The TRW Pulsed Inductive Thruster (PIT) is an electromagnetic propulsion system that can provide high thrust efficiency over a wide range of specific impulse values. In its basic form, the PIT consists of a flat spiral coil covered by a thin dielectric plate. A pulsed gas injection nozzle distributes a thin layer of gas propellant across the plate surface at the same time that a pulsed high current discharge is sent through the coil. The rising current creates a time varying magnetic field, which in turn induces a strong azimuthal electric field above the coil. The electric field ionizes the gas propellant and generates an azimuthal current flow in the resulting plasma. The current in the plasma and the current in the coil flow in opposite directions, providing a mutual repulsion that rapidly blows the ionized propellant away from the plate to provide thrust. The thrust and specific impulse can be tailored by adjusting the discharge power, pulse repetition rate, and propellant mass flow, and there is minimal if any erosion due to the electrodeless nature of the discharge. Prior single-shot experiments performed with a 1-meter diameter version of the PIT at TRW demonstrated specific impulse values between 2,000 seconds and 8,000 seconds, with thruster efficiencies exceeding 55% for ammonia and hydrazine propellants. This paper outlines current and planned activities to transition the single shot device into a multiple repetition rate thruster capable of supporting future DOD and NASA strategic enterprise missions.

Hrbud, Ivana↗

NASA NTRS2000

Beyond Coordination: Joint Planning and Program Execution. The IHPRPT Materials Working Group

"Partnership is more than just coordination," stated then-Commander of the Air Force Research Laboratory (AFRL), Major General Dick Paul (USAF-Ret), at this year's National Space and Missile Materials Symposium. His comment referred to the example of the joint planning and program execution provided by the Integrated High Payoff Rocket Propulsion Technology (IHPRPT) Materials Working Group (IMWG). Most people agree that fiscal pressures imposed by shrinking budgets have made it extremely difficult to build upon our existing technical capabilities. In times of sufficient budgets, building advanced systems poses no major difficulties. However, with today's budgets, realizing enhanced capabilities and developing advanced systems often comes at an unaffordable cost. Overcoming this problem represents both a challenge and an opportunity to develop new business practices that allow us to develop advanced technologies within the restrictions imposed by current funding levels. Coordination of technology developments between different government agencies and organizations is a valuable tool for technology transfer. However, rarely do the newly developed technologies have direct applicability to other ongoing programs. Technology requirements are typically determined up-front during the program planning stage so that schedule risk can be minimized. The problem with this process is that the costs associated with the technology development are often borne by a single program. Additionally, the potential exists for duplication of technical effort. Changing this paradigm is a difficult process but one that can be extremely worthwhile should the right opportunity arise. The IMWG is one such example where NASA, the DoD, and industry have developed joint requirements that are intended to satisfy multiple program needs. More than mere coordination, the organizations comprising the group come together as partners, sharing information and resources, proceeding from a joint roadmap.

Stropki, Michael A.↗

NASA NTRS2000

2000 Digital Avionics Highlights

This article summarizes the highlights of recent events and developments in digital avionics in commercial aviation, military systems, and space. This article is about 1,200 words long. Information for the article was collected from other NASA centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology and similar sources.

Polites, Michael E.↗

NASA NTRS2000

2000 Guidance, Navigation, and Control Highlights

This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

Polites, Michael E.↗

NASA NTRS2000

SUPREM-DSMC: A New Scalable, Parallel, Reacting, Multidimensional Direct Simulation Monte Carlo Flow Code

An AFRL/NRL team has recently been selected to develop a scalable, parallel, reacting, multidimensional (SUPREM) Direct Simulation Monte Carlo (DSMC) code for the DoD user community under the High Performance Computing Modernization Office (HPCMO) Common High Performance Computing Software Support Initiative (CHSSI). This paper will introduce the JANNAF Exhaust Plume community to this three-year development effort and present the overall goals, schedule, and current status of this new code.

Campbell, David↗

NASA NTRS2000

First NASA Aviation Safety Program Weather Accident Prevention Project Annual Review

The goal of this Annual Review was to present NASA plans and accomplishments that will impact the national aviation safety goal. NASA's WxAP Project focuses on developing the following products: (1) Aviation Weather Information (AWIN) technologies (displays, sensors, pilot decision tools, communication links, etc.); (2) Electronic Pilot Reporting (E-PIREPS) technologies; (3) Enhanced weather products with associated hazard metrics; (4) Forward looking turbulence sensor technologies (radar, lidar, etc.); (5) Turbulence mitigation control system designs; Attendees included personnel from various NASA Centers, FAA, National Weather Service, DoD, airlines, aircraft and pilot associations, industry, aircraft manufacturers and academia. Attendees participated in discussion sessions aimed at collecting aviation user community feedback on NASA plans and R&D activities. This CD is a compilation of most of the presentations presented at this Review.

Colantonio, Ron↗

NASA NTRS2001

Highly Effective, Low Toxicity, Low Environmental Impact Total Flooding Fire Suppressants

Halon 1301 (CF3Br) has been used for decades as the primary fire suppression agent for areas where powder agents cannot be used because of concerns for sensitive equipment. Halon 1301 is an excellent extinguishing agent, effective at about 3% in air and quite non-toxic. It has an effective exposure limit much greater than its extinguishing concentration, so it can be used in normally occupied areas. The ability of a chemical to destroy stratospheric ozone is its ozone-depletion potential (ODP). ODP is the amount of ozone destroyed per pound of a chemical, relative to the standard CFC-11 with an ODP = 1.0. Because halons have been implicated in stratospheric ozone depletion, their production was stopped at the end of 1995 under the provisions of the Montreal Protocol plus later amendments. In the US, the Clean Air Act Amendments of 1990, Presidential directives, and DoD Directive 6050.9 implemented this phaseout. These regulations and penalties have provided strong incentives for US businesses to decrease CFC use. The Omnibus Budget Reconciliation Act of 1989 mandates high Federal taxes on CFCs and halons, designed to price them out of the market. The taxes also capture for the government the windfall profits that would otherwise go to producers as scarcity drives up prices. Several replacements have been developed for Halon 1301. One is carbon dioxide, which has been used as a firefighting agent for many years. However, a high concentration of carbon dioxide is necessary to inert fuels. The effective concentration for inerting with carbon dioxide is approximately 29%, which is above the concentration lethal to humans. HFC-227ea is being used extensively to replace Halon 1301 systems in nominally occupied areas and some normally unoccupied areas. However, since the effective concentration of HFC-227ea is about three to four times that of Halon 1301 the extinguishing systems have to be larger and new extinguishing systems have to be installed. HFC-125 is also being sold as an extinguishing agent (Nimitz). It has problems similar to HFC-227ea, with a greater concentration needed for effectiveness and the need to use a larger system. This is a particularly onerous penalty in aircraft and spacecraft, where weight and space are extremely important, and substitution is often impossible in existing aircraft due to space limitations.

Glass, S. M.↗