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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Apollo Spacesuit Modifications for the Apollo-Soyuz Test Project (ASTP) Spacesuit

With over 50 years of experience with NASA spacesuit development and operations, as well as for early U.S. Air Force pressure suits, Jim McBarron shared his significant knowledge about modifications to the Apollo spacesuit for use in the Apollo-Soyuz Test Project (ASTP). This included requirements and design changes implemented to establish the ASTP spacesuit design baseline. Additionally, he identified Apollo spacesuit contact details including quantity of spacesuits delivered to support the Apollo and Skylab Programs, and the ASTP. He concluded by identifying a summary of noteworthy lessons learned with recommendations for future spacesuit development.

McBarron, James W., II↗
NASA NTRS2016

Control Systems with Normalized and Covariance Adaptation by Optimal Control Modification

Disclosed is a novel adaptive control method and system called optimal control modification with normalization and covariance adjustment. The invention addresses specifically to current challenges with adaptive control in these areas: 1) persistent excitation, 2) complex nonlinear input-output mapping, 3) large inputs and persistent learning, and 4) the lack of stability analysis tools for certification. The invention has been subject to many simulations and flight testing. The results substantiate the effectiveness of the invention and demonstrate the technical feasibility for use in modern aircraft flight control systems.

Nguyen, Nhan T.↗
NASA NTRS2015

Synthesis and Modification of Holey Graphene for Energy Storage

Porous graphene materials have recently drawn significant interest for energy storage applications due to the effective use of the graphitic surface area provided by the pores. Holey graphene is a type of porous graphene with pores in the form of physical through thickness holes. This type of porous graphene provides a unique morphology that allows for effective transport of molecular species through the graphene plane. Therefore, as we recently demonstrated, holey graphene could be advantageous in the preparation of electrodes in supercapacitors with high volumetric performance.1 We have developed methodologies to scalably prepare holey graphene materials with or without the use of catalysts (Figure 1).1,2 In this presentation, we will discuss the choice of synthetic strategies and experimental conditions on the morphology and physical properties of holey graphene (Figure 2) and the effect on their electrochemical properties. We will also present the results on the further modification of holey graphene to study their physical and chemical properties, especially with regard to the stability and chemical reactivity of carbons located around the edges of the holes.

Lin, Yi↗
NASA NTRS2017

Performance Optimizing Adaptive Control with Time-Varying Reference Model Modification

This paper presents a new adaptive control approach that involves a performance optimization objective. The control synthesis involves the design of a performance optimizing adaptive controller from a subset of control inputs. The resulting effect of the performance optimizing adaptive controller is to modify the initial reference model into a time-varying reference model which satisfies the performance optimization requirement obtained from an optimal control problem. The time-varying reference model modification is accomplished by the real-time solutions of the time-varying Riccati and Sylvester equations coupled with the least-squares parameter estimation of the sensitivities of the performance metric. The effectiveness of the proposed method is demonstrated by an application of maneuver load alleviation control for a flexible aircraft.

Adaptive Control↗
NASA NTRS2018

Time-Varying Modification of Reference Model for Adaptive Control with Performance Optimization

This paper presents a new adaptive control ap- proach that involves a performance optimization objective. The control synthesis involves the design of a performance optimizing adaptive controller from a subset of control inputs. The resulting effect of the performance optimizing adaptive controller is to modify the initial reference model into a time-varying reference model which satisfies the performance optimization requirement obtained from an optimal control problem. The time-varying reference model modification is accomplished by the real-time solutions of the time-varying Riccati and Sylvester equations coupled with the least-squares parameter estimation of the sen- sitivities of the performance metric. The effectiveness of the proposed method is demonstrated by an application of maneuver load alleviation control for a flexible aircraft.

Adaptive Control↗
NASA NTRS2018

Modification of Radiator Pigments by Atomic Layer Deposition (ALD)

The optical and physical properties of spacecraft radiator coatings are dictated by orbital environmental conditions. For example, coatings must adequately dissipate charge buildup when orbital conditions, such as polar, geostationary or gravity neutral, result in surface charging. Current dissipation techniques include depositing a layer of ITO (indium tin oxide) on the radiator surface in a high temperature process. Other examples include the application of variable emittance coatings such as the use of VO2 to optimize radiator size, allowing for a decrease in heater power budget. The application of these enhanced coatings must be such that the properties in question are tailored to mission-specific requirements. Modification of these coatings can be accomplished during coating application preprocessing by using a deposition technique prevalent in the semiconductor micro processing industry called Atomic Layer Deposition (ALD). The preprocessing is rendered directly on the coating dry pigment before binding. ALD is a cost effective nano-manufacturing technique that allows for the conformal coating of substrates with atomic-level thickness control in a benign temperature and pressure environment. Through the introduction of paired precursor gases, thin films can be deposited on a myriad of substrates ranging from glass, polymers, aerogels, metals, powders, and other high aspect-ratio micro- and nano-structures. By providing atomic-level control, where single layers of atoms can be deposited, the fabrication of metal transparent films, precise nano-laminates, and coatings of nano-channels and pores is achievable. We have demonstrated a method for the ALD of In2O3 and ITO films on a variety of substrates from Si(100) wafers, glass slides, and on Z93P pigments (patent pending). The results indicate excellent growth of 4-22 nm thick films demonstrating an order of magnitude decrease in resistivity on the pigments.

ITO↗
NASA NTRS2018

Patterns in Mobility and Modification of Middle and High-Latitude Southern Hemisphere Dunes on Mars

Change detection analyses of aeolian bedforms (dunes and ripples), using multitemporal imagesacquired by the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE), canreveal migration of bedforms on Mars. Here we investigated bedform mobility (evidence of wind-drivenmigration or activity), from analysis of HiRISE temporal image pairs, and dune field modification (i.e., apparentpresence/lack of changes or degradation due to nonaeolian processes) through use of a dune stability indexor SI (1–6; higher numbers indicating increasing evidence of stability/modification). Combining mobility dataand SI for 70 dune fields south of 40°S latitude, we observed a clear trend of decreasing bedform mobility withincreasing SI and latitude. Both dunes and ripples were more commonly active at lower latitudes, althoughsome high-latitude ripples are migrating. Most dune fields with lower SIs (3) were found to be active whilethose with higher SIs were primarily found to be inactive. A shift in prevalence of active to apparently inactivebedforms and to dune fields with SI 2 occurs at ~60°S latitude, coincident with the edge of highconcentrations of H2O-equivalent hydrogen observed by the Mars Odyssey Neutron Spectrometer. This result isconsistent with previous studies suggesting that stabilizing agents, such as ground ice, likely stabilize bedformsand limit sediment availability. Observations of active dune fields with morphologies indicative of stability(i.e., migrating ripples in SI = 3 dune fields) may have implications for episodic phases of reworking or dunebuilding, and possibly geologically recent activation or stabilization corresponding to shifts in climate

Banks, Maria E.↗
NASA NTRS2019

Overview of the X-57 Structure Requirements, Modifications, and Airworthiness

This presentation is overview of the X-57 structural design requirements for the propeller systems and power systems, modifications to the existing Tecnam aircraft, and as well as the structural airworthiness process which includes the analysis and ground testing of the composite wing.'

structural mechanics↗
NASA NTRS2019

Technology Development for the Modification of High Aspect Ratio Geometries for Thermal and Environmental Control

A key technology development driver in environmental control systems and next generation optics are discussed utilizing thin film development borrowed from the semiconductor industry. The optical and physical properties of spacecraft radiator coatings are dictated by orbital environmental conditions. For example, coatings must adequately dissipate charge buildup when orbital conditions, such as polar, geostationary or gravity neutral, result in surface charging. Current dissipation techniques include depositing a layer of ITO (indium tin oxide) on the radiator surface in a high temperature process. The application of these enhanced coatings must be such that the properties in question are tailored to mission-specific requirements. The multi-billion-dollar semiconductor industry has adopted Atomic Layer Deposition (ALD) for self-assembly and atomic-scale placement. ALD is a cost-effective nanoadditive-manufacturing technique that allows for the conformal coating of substrates with atomic control in a benign temperature and pressure environment. By using ALD, modification of these coatings can be accomplished during coating application preprocessing. The preprocessing is rendered directly on the coating dry pigment before binding. Through the introduction of paired precursor gases, thin films can be deposited on a myriad of substrates ranging from glass, polymers, aerogels, metals, powders, and other high aspect-ratio micro- and nano- structures. By providing atomic-level control, where single layers of atoms can be deposited, the fabrication of metal transparent films, precise nano-laminates, and coatings of nano-channels and pores is achievable. A method has been demonstrated for the ALD of In2O3 and films on a variety of substrates from Si(100) wafers, glass slides, and on Z93P pigments resulting in a direct spaceflight application. Results will be presented that verify the chemical composition of ALD pigments and charge dissipation properties when the pigment goes through its binding and coating process and we present early results of ALD for carbon nanotube formation and encapsulation.

Dwivedi, Vivek H.↗
NASA NTRSDate not supplied

Integrated GNC Modifications and Performance Assessments for the Mars Ascent Vehicle, Spin-Stabilized Upper Stage Configuration

The objective of the Mars Ascent Vehicle (MAV), an element of the Mars Sample Return (MSR) campaign, is to successfully transport Martian surface samples from the Martian surface to a stable Low-Martian Orbit. Complete autonomy is required throughout ascent, and orbital insertion is constrained by tight dispersion boundaries. Given mass requirements to merely transport the MAV onto the Martian surface, reducing the total mass of the MAV reduces stress on all other campaign elements. An unguided, spin-stabilized second stage MAV allows for lower overall vehicle mass, at the cost of reduced GNC capability. This paper presents GNC modifications developed and employed to improve the performance of an unguided, spin-stabilized second stage MAV configuration. These updates include a predictive calculation scheme to solve the spin-stabilized attitude necessary for successful orbital insertion, and a spin-stabilized control law for a preliminary low-rate first stage spin-up. Trades were conducted focusing on first and second stage low-rate and high-rate spin rates (and other factors) in MSFC's MANTIS toolkit through 6-degree-of-freedom simulation and Monte Carlo analysis, and are presented here.

Dane Erickson↗
NASA NTRS2021

Mineralogy and Surface Modification of Small Grains Recovered from the Asteroid 162173 Ryugu

Surface material on airless bodies exposed to the interplanetary space experienced the bombardment by low-energy (~1 keV/nucleon) solar wind particles and micrometeoroid impacts. These processes, alongside the resultant surface modifications, and spectral darkening and reddening are called space weathering [1]. Space weathering of the Moon and the asteroid 25143 Itokawa belonging to S-type asteroids have been investigated intensively [e.g. 1-5]. The Hayabusa 2 spacecraft returned samples from the asteroid 162173 Ryugu C-type asteroid. The Ryugu samples give us the first opportunity to investigate space weathering of C-type asteroids. The Mineralogy-Petrology Fine (M-P F or Sand) sub-team mainly investigates small grains (typically ~100 μm across). The main purposes of the M-P F sub-team are to understand the variationof mineralogy of the allocated grains and the nature of space weathering of the asteroid Ryugu. The M-P F sub-team is comprised of 51 members belonging to 25 universities and laboratories

T. Noguchi↗
NASA NTRSDate not supplied

Time-Varying Reference Model Modification of Adaptive Control with Multi-Objective Performance Optimization

This paper presents an adaptive control approach that modifies a reference model in order to satisfy a multi-objective optimization of two performance signals: a linear signal and a quadratic signal. The time varying reference model modification is accomplished by the real-time solutions of the time-varying Riccati and Sylvester equations coupled with the least-squares parameter estimation of the sensitivities of the performance signals to be minimized. The effectiveness of the proposed method is to be demonstrated by a flight control application of maneuver load alleviation and drag minimization.

Adaptive Control↗
NASA NTRS2023

Passive Rocket Diffuser Testing: Performance Similitude Via Nozzle Contour Modification

Subscale rocket testing offers a chance to examine exhaust plume behavior and prove out auxiliary systems early in a development cycle, when the cost of design iteration remains low. Despite the utility of experimentation, perfect similitude between a rocket engine and a scaled model is unobtainable; choices must be made to prioritize the reproduction of certain parameters at the expense of others. The experimentalist’s toolkit contains a variety of techniques to achieve this selective similarity. Determination of the appropriate tool is dependent on a test series’ specific objectives, facility limitations, and financial considerations. Preservation of full nozzle geometry is crucial if its internal flow is of interest. However, subscale thrusters often serve as a simple plume source in the evaluation of adjacent phenomena: vehicle base pressures, retropropulsive flows, supersonic diffuser performance, refractory erosion, deflector cooling, impingement shock structures, etc. In such cases, it may be permissible to rework the nozzle geometry to compensate for discrepancies in subscale propellant pressure, temperature, or chemical composition. Thrust, pressure, Mach number, heat flux, and myriad other parameters can be used to ground the altered designs. Subscale diffuser testing at the full chamber pressure of flight hardware is occasionally infeasible. It is hypothesized that, absent a means of backpressure reduction, comparable performance may be obtained for a prescribed motive fluid by maintaining scaled engine mass flow and nozzle exit geometry at the expense of throat geometry, exit pressure, and Mach number. The present work offers discrete empirical support for this mass-flow-based approach to contour modification.

subscale↗
NASA NTRSDate not supplied

Effect of Tungsten L-PBF Feedstock Modification on Performance in Bending

Additively manufactured tungsten is a candidate refractory material for high-temperature aerospace and nuclear fusion/fission applications. The printability of pure tungsten is challenged by cracking defects arising from the metal’s high ductile-to-brittle transition temperature and low solubility of interstitial impurities. Furthermore, the cast microstructure inherent to the laser powder bed fusion (L-PBF) process has limited strength compared to worked microstructures common in wrought tungsten. Aside from process-related techniques to mitigate defects and increase strength (e.g., heated build chambers, multi-laser systems, low oxygen environmental control, etc.), micro-alloying additions can positively influence tungsten printability. In this work, pure tungsten L-PBF feedstock was modified with 1 wt% additions of ceramic compound nano-powders. Wrought and printed bars were evaluated in four-point bending. Flexural strength and fractography were primary means of comparison to assess the effect of the feedstock modification on printed tungsten mechanical performance.

Tungsten-based alloys↗
NASA NTRS2021

Regolith Adaptive Modification Systems (Rams) - Final Report

Establishing human habitation on the Moon or Mars requires a palette of reaction chemistries for deconstructing extraterrestrial soils to extract structural metals, fuels, and propellants, as well as consolidating the soils into load-bearing forms. This report outlines progress related to the fundamental chemistry of in-situ resource utilization that is the focus of our Regolith Adaptive Modification System (RAMS) NIAC project. The RAMS concept is a breakthrough approach for preparing surfaces for early landing sites–and subsequent settlement operations–on the Lunar and Martian surface, among others. The RAMS concept is aligned with aspirations and capabilities of planned NASA Artemis mission. The approach is predicated on the sequential delivery of microcapsules onto lunar and Martian surfaces, which upon rupture, release payloads that react with regolith to yield geopolymerized subsurface slabs and surface high-strength steel skin and anchors . Through successively more exothermic reactions, we are seeking to build subsurface geopolymer slabs and use thermite reactions to constitute micro-alloyed advanced high-strength steel (AHSS) and Ti—Al—V pads on surfaces of planetary bodies, thereby circumventing the need for energy-intensive sintering technologies. As a precursor delivery system used to constitute landingpads, RAMS can be scaled for robotic, human-class, and more prominent (i.e., Starship) landers and will be configured within pressurized delivery systems that use radio beacons to outline coordinates for precision landings. Microcapsule delivery systems are designed to impel precursors (nanothermite mixtures and organosilanes), which activate in response to stress, heat, or impact to constitute deep geopolymerized slabs and AHSS skins. Dust mitigation is accomplished by reaction/solidification chemistry that yields a subsurface slab and advanced high-strength steel skin and anchors.

2021 NIAC Phase I↗
DOE OSTI2021

System and method for monitoring atomic absorption during a surface modification process

A processing system monitors and/or controls a surface modification process occurring on a substrate within a processing chamber. An optical processing module having a light emission submodule to output a generated light signal and an optical detection submodule to detect a resultant light signal, is connected via fiber optic cables to light illuminating and light receiving components located within the chamber. A processor determines an amount of atomic absorption by an atomic element encountered by a probing beam passing between the illuminating and receiving components, based on the intensity of the generated light signal, the intensity of the received light signal and optionally the spontaneous emission of the atomic element in the absence of illumination by a probing beam. Based on the determined amount, the system derives a plurality of parameters of the modified substrate, their spatial and temporal uniformity, and information about process conditions in the processing chamber.

Atanasoff, George↗