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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Dust Mitigation: Impacts & Opportunities for Science on the Lunar South Pole

Lunar dust will be a feature of all lunar surface science investigations, whether welcome or not. While lunar dust may pose problems for some investigations, it is also the subject of many critical scientific discoveries made since the Apollo days. Dust mitigation, or learning how to work with and around the inevitable dust we will encounter on the surface, is not a new concept. However, new initiatives throughout NASA are underway in an effort to tackle dust mitigation strategically for the Artemis program. Dust mitigation efforts and technologies will enable successful lunar surface science investigations.

lunar dust↗
NASA NTRS2003

Models Required to Mitigate Impacts of Space Weather on Space Systems

This viewgraph presentation attempts to develop a model of factors which need to be considered in the design and construction of spacecraft to lessen the effects of space weather on these vehicles. Topics considered include: space environments and effects, radiation environments and effects, space weather drivers, space weather models, climate models, solar proton activity and mission design for the GOES mission. The authors conclude that space environment models need to address issues from mission planning through operations and a program to develop and validate authoritative space environment models for application to spacecraft design does not exist at this time.

Barth, Janet L.↗
NASA NTRS2019

Incorporation of Functionalized Polyhedral Oligomeric Silsesquioxane Nanomaterials as Reinforcing Agents for Impact Ice Mitigating Coatings

In-flight, aircraft are exposed to a wide range of environments. One commonly exposed environment are clouds containing super-cooled water droplets. These water drop- lets exist in a metastable state below the freezing point of water, in the range of 0 to -20°C. As the vehicle impacts the droplets, latent heat is released and within milliseconds the droplets convert to ice. This process is referred to as impact icing or in-flight icing.1 Impact icing is a major concern for aircraft since it can lead to degraded aerodynamic performance and, if left un- treated, can lead to loss of the vehicle. Active approaches (i.e., pneumatic boots, heated air ducts) typically utilized in mitigating in-flight ice accretion significantly increases vehicle weight and cannot be applied to all aircraft.1-3 A passive approach based on coatings is desired, but durability issues are a concern, especially on the wing leading edge.3 Nanomaterials have been shown to afford significant improvement in coating and composite physical properties at low loading levels.4 In this study, Polyhedral Oligomeric Silsesquioxane (POSS) nanomaterials have been shown to increase coating durability. Also, with wide variety of functionalities present on the arm structure, POSS nanomaterials have been shown to readily alter coating surface chemistry to mitigate impact ice adhesion from -16 to -8°C in a simulated in-flight icing environment.

Beck, Devon M.↗
NASA NTRS2015

An Innovative Solution to NASA's NEO Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development

This paper presents the results of a NASA Innovative Advanced Concept (NIAC) Phase 2 study entitled "An Innovative Solution to NASA's Near-Earth Object (NEO) Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development." This NIAC Phase 2 study was conducted at the Asteroid Deflection Research Center (ADRC) of Iowa State University in 2012-2014. The study objective was to develop an innovative yet practically implementable mitigation strategy for the most probable impact threat of an asteroid or comet with short warning time (< 5 years). The mitigation strategy described in this paper is intended to optimally reduce the severity and catastrophic damage of the NEO impact event, especially when we don't have sufficient warning times for non-disruptive deflection of a hazardous NEO. This paper provides an executive summary of the NIAC Phase 2 study results. Detailed technical descriptions of the study results are provided in a separate final technical report, which can be downloaded from the ADRC website (www.adrc.iastate.edu).

NEO Impact Threat Mitigation↗
NASA NTRS2014

An Innovative Solution to NASA's NEO Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development

This final technical report describes the results of a NASA Innovative Advanced Concept (NIAC) Phase 2 study entitled "An Innovative Solution to NASA's NEO Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development." This NIAC Phase 2 study was conducted at the Asteroid Deflection Research Center (ADRC) of Iowa State University in 2012-2014. The study objective was to develop an innovative yet practically implementable solution to the most probable impact threat of an asteroid or comet with short warning time (less than 5 years). The technical materials contained in this final report are based on numerous technical papers, which have been previously published by the project team of the NIAC Phase 1 and 2 studies during the past three years. Those technical papers as well as a NIAC Phase 2 Executive Summary report can be downloaded from the ADRC website (www.adrc.iastate.edu).

NEO↗
NASA NTRS2017

Mitigating the Impact of Sensor Uncertainty on Unmanned Aircraft Operations

Without a pilot onboard an aircraft, a Detect-and-Avoid (DAA) system, in conjunction with surveillance sensors, must be used to provide the remotely-located Pilot-in-Command sufficient situational awareness in order to keep the Unmanned Aircraft (UA) safely separated from other aircraft. To facilitate safe operations of UA within the U.S.' National Airspace System, the uncertainty associated with surveillance sensors must be accounted for. An approach to mitigating the impact of sensor uncertainty on achievable separation has been developed to support technical requirements for DAA systems.

Jack, Devin P.↗
NASA NTRS2016

Engineering Polymer Blends for Impact Damage Mitigation

Structures containing polymers such as DuPont's Surlyn® 8940, demonstrate puncture healing when impacted by a 9 millimeter projectile traveling from speeds near 300 meters per second (1,100 feet per second) to hypervelocity impacts in the micrometeoroid velocity range of 5 kilometers per second (16,000 feet per second). Surlyn® 8940 puncture heals over a temperature range of minus 30 degrees Centigrade to plus 70 degrees Centigrade and shows potential for use in pressurized vessels subject to impact damage. However, such polymers are difficult to process and limited in applicability due to their low thermal stability, poor chemical resistance and overall poor mechanical properties. In this work, several puncture healing engineered melt formulations were developed. Moldings of melt blend formulations were impacted with a 5.56 millimeter projectile with a nominal velocity of 945 meters per second (3,100 feet per second) at about 25 degrees Centigrade, 50 degrees Centigrade and 100 degrees Centigrade, depending upon the specific blend being investigated. Self-healing tendencies were determined using surface vacuum pressure tests and tensile tests after penetration using tensile dog-bone specimens (ASTM D 638-10). For the characterization of tensile properties both pristine and impacted specimens were tested to obtain tensile modulus, yield stress and tensile strength, where possible. Experimental results demonstrate a range of new puncture healing blends which mitigate damage in the ballistic velocity regime.

Gordon, Keith L.↗
NASA NTRSDate not supplied

Impact Icing Mitigation

Explore the source record for details and available documents.

icing, AERTS Jr, rapid impact deformation, Tabe ab↗
NASA NTRS2009

Integration of Weather Data into Airspace and Traffic Operations Simulation (ATOS) for Trajectory- Based Operations Research

Explicit integration of aviation weather forecasts with the National Airspace System (NAS) structure is needed to improve the development and execution of operationally effective weather impact mitigation plans and has become increasingly important due to NAS congestion and associated increases in delay. This article considers several contemporary weather-air traffic management (ATM) integration applications: the use of probabilistic forecasts of visibility at San Francisco, the Route Availability Planning Tool to facilitate departures from the New York airports during thunderstorms, the estimation of en route capacity in convective weather, and the application of mixed-integer optimization techniques to air traffic management when the en route and terminal capacities are varying with time because of convective weather impacts. Our operational experience at San Francisco and New York coupled with very promising initial results of traffic flow optimizations suggests that weather-ATM integrated systems warrant significant research and development investment. However, they will need to be refined through rapid prototyping at facilities with supportive operational users We have discussed key elements of an emerging aviation weather research area: the explicit integration of aviation weather forecasts with NAS structure to improve the effectiveness and timeliness of weather impact mitigation plans. Our insights are based on operational experiences with Lincoln Laboratory-developed integrated weather sensing and processing systems, and derivative early prototypes of explicit ATM decision support tools such as the RAPT in New York City. The technical components of this effort involve improving meteorological forecast skill, tailoring the forecast outputs to the problem of estimating airspace impacts, developing models to quantify airspace impacts, and prototyping automated tools that assist in the development of objective broad-area ATM strategies, given probabilistic weather forecasts. Lincoln Laboratory studies and prototype demonstrations in this area are helping to define the weather-assimilated decision-making system that is envisioned as a key capability for the multi-agency Next Generation Air Transportation System [1]. The Laboratory's work in this area has involved continuing, operations-based evolution of both weather forecasts and models for weather impacts on the NAS. Our experience has been that the development of usable ATM technologies that address weather impacts must proceed via rapid prototyping at facilities whose users are highly motivated to participate in system evolution.

Peters, Mark↗
NASA NTRS2012

Aquarius Radiometer RFI Detection, Mitigation, and Impact Assessment

The Aquarius/SAC-D satellite was launched on 10 June 2011 into a sun-synchronous polar orbit and the Aquarius microwave radiometers [1] became operational on 25 August 2011. Since that time, it has been measuring brightness temperatures at 1.4 GHz with vertical, horizontal and 3rd Stokes polarizations . Beginning well before the launch, there has been the concern that Radio Frequency Interference (RFI) could have an appreciable presence. This concern was initiated by, among other things, its prevalence in both early [2] and more recent [3,4] aircraft field experiments using 1.4 GHz radiometers, as well as by the strong RFI environment encountered during the recent ESA SMOS mission, also at 1.4 GHz [5]. As a result, a number of methods for RFI detection and mitigation have been developed and tested. One in particular, "glitch detection" and "pulse blanking" mitigation has been adapted for use by Aquarius [6, 7]. The early on-orbit performance of the Aquarius RFI detection and mitigation algorithm is presented here, together with an assessment of the global RFI environment at 1.4 GHz which can be derived from the Aquarius results.

Ruf, Christopher↗
NASA NTRS2017

Temperature and Snowfall in Western Queen Maud Land Increasing Faster than Climate Model Projections

East Antarctic Ice Sheet (EAIS) mass balance is largely driven by snowfall. Recently, increased snowfall in Queen Maud Land led to years of EAIS mass gain. It is difficult to determine whether these years of enhanced snowfall are anomalous or part of a longer-term trend, reducing our ability to assess the mitigating impact of snowfall on sea level rise. We determine that the recent snowfall increases in western Queen Maud Land (QML) are part of a long-term trend (+5.2 +/- 3.7% decade(exp -1)) and are unprecedented over the past two millennia. Warming between 1998 and 2016 is significant and rapid (+1.1 +/- 0.7 C decade(exp -1)). Using these observations, we determine that the current accumulation and temperature increases in QML from an ensemble of global climate simulations are too low, which suggests that projections of the QML contribution to sea level rise are potentially overestimated with a reduced mitigating impact of enhanced snowfall in a warming world.

WAIS↗
NASA NTRS2010

Shuttle Environmental Assurance: Brominated Flame Retardants - Concerns, Drivers, Potential Impacts and Mitigation Strategies

Brominated Flame Retardants (BFRs) are widely used in the manufacture of electrical and electronic components and as additives in formulations for foams, plastics and rubbers. The United States (US) and the European Union (EU)have increased regulation and monitoring of of targeted BFRs, such as Polybrominated Diphenyl Ethers (PBDEs) due to the bioaccumulative effects in humans and animals. In response, manufacturers and vendors of BFR-containing materials are changing flame-retardant additives, sometimes without notifying BFR users. In some instances, Deca-bromodiphenylether (Deca-BDE) and other families of flame retardants are being used as replacement flame retardants for penta-BDE and octa-BDE. The reformulation of the BFR-containing material typically results in the removal of the targeted PBDE and replacement with a non-PBDE chemical or non-targeted PBDE. Many users of PBDE -based materials are concerned that vendors will perform reformulation and not inform the end user. Materials performance such as flammability, adhesion , and tensile strength may be altered due to reformulation. The requalification of newly formulated materials may be required, or replacement materials may have to be identified and qualified. The Shuttle Enviornmental Assurance (SEA) team indentified a risk to the Space Shuttle Program associated with the possibility that targeted PBDEs may be replaced without notification. Resultant decreases in flame retardancy, Liquid Oxygen (LOX) compatibility, or material performance could have serious consequences.

Clark-Ingram, Marceia↗
NASA NTRS2015

Toward an Integrated Solution to Mitigate the Impact of Volcanic Ash to Aviation

The science community is making a concerted effort to improve the reliability of dispersion models for the forecasting of volcanic ash plumes. Toward this end, it has been observed that the assimilation of diverse, accurate and frequent surface, airborne and satellite observations of the source and distal ash plumes may hold the key. Various international research organizations and operational agencies make these observations using a variety of active and passive remote sensing systems and use them to initialize atmospheric trajectory and dispersion models. These observation systems range from surface LIDAR and ceilometers, to airborne radiometers and nephelometers, to satellite radiometers, multi-spectral imagers, LIDAR and UV-photometers. None of these systems alone is a panacea, however, their synergistic application holds great promise toward solving this complex problem. Additionally, the aeronautical and science communities are working to better understand the quantitative thresholds and tolerances of aviation systems to volcanic ash to better inform scientists of the accuracy requirements for dispersion model forecasts. A number of the most recent and promising efforts in all of these area are discussed in this presentation.

Murray, John J.↗
NASA NTRS2015

Relative Impacts of Mitigation, Temperature, and Precipitation on 21st-Century Megadrought Risk in the American Southwest

Megadroughts are comparable in severity to the worst droughts of the 20th century but are of much longer duration. A megadrought in the American Southwest would impose unprecedented stress on the limited water resources of the area, making it critical to evaluate future risks not only under different climate change mitigation scenarios but also for different aspects of regional hydroclimate. We find that changes in the mean hydroclimate state, rather than its variability, determine megadrought risk in the American Southwest. Estimates of megadrought probabilities based on precipitation alone tend to underestimate risk. Furthermore, business-as-usual emissions of greenhouse gases will drive regional warming and drying, regardless of large precipitation uncertainties. We find that regional temperature increases alone push megadrought risk above 70, 90, or 99% by the end of the century, even if precipitation increases moderately, does not change, or decreases, respectively. Although each possibility is supported by some climate model simulations, the latter is the most common outcome for the American Southwest in Coupled Model Intercomparison 5 generation models. An aggressive reduction in global greenhouse gas emissions cuts megadrought risks nearly in half.

risk↗
NASA NTRSDate not supplied

Mitigating the Impact of Momentum Unloads on Station Keeping Around Libration Point Orbits

The Space Weather Follow On (SWFO) observatory will observe the Sun from L1, collecting solar wind data and coronal imagery, while providing early warning for space weather events. SWFO is a ride-share mission on SpaceX Falcon9 that is carrying IMAP. The spacecraft will be operated by NOAA and is expected to launch in February 2025. In order to meet NOAA’s operational requirements SWFO must maintain a Sun-Earth-Vehicle (SEV) angle between 4 and 13 degrees for at least 5 years. This constraint drives the size of the Lissajous orbit. SWFO is required keep a Sun pointing attitude in order to perform the Sun observations. Frequent Momentum Unloads are required to desaturate its reaction wheals. Station-keeping maneuvers are required to stay in orbit around L1, they are planned to be performed every 30 days.

Libration Point Orbits↗