Search NASA⌕ Search

SEARCH · Search NASA

Results for “operating envelope”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32

Use of control umbilicals as a deployment mode for free flying telerobotic work systems

Work to date on telerobotic work systems for use in space generally consider two deployment modes, free flying, or fixed within a limited work envelope. Control tethers may be employed to obtain a number of operational advantages and added flexibility in the basing and deployment of telerobotic work systems. Use of a tether allows the work system to be separated into two major modules, the remote work package and the control module. The Remote Work Package (RWP) comprises the free flying portion of the work system while the Control Module (CM) remains at the work system base. The chief advantage of this configuration is that only the components required for completion of the work task must be located at the work site. Reaction mass used in free flight is stored at the Control module and supplied to the RWP through the tether, eliminating the need for the RWP to carry it. The RWP can be made less massive than a self contained free flying work system. As a result, reaction mass required for free flight is lower than for a self contained free flyer.

Kuehn, J. S.↗

Resource envelope concepts for mission planning

Seven proposed methods for creating resource envelopes for Space Station Freedom mission planning are detailed. Four reference science activity models are used to illustrate the effect of adding operational flexibility to mission timelines. For each method, a brief explanation is given along with graphs to illustrate the application of the envelopes to the power and crew resources. The benefits and costs of each method are analyzed in terms of resource utilization. In addition to the effect on individual activities, resource envelopes are analyzed at the experiment level.

Ibrahim, K. Y.↗

Human Factors Vehicle Displacement Analysis: Engineering In Motion

While positioned on the launch pad at the Kennedy Space Center, tall stacked launch vehicles are exposed to the natural environment. Varying directional winds and vortex shedding causes the vehicle to sway in an oscillating motion. The Human Factors team recognizes that vehicle sway may hinder ground crew operation, impact the ground system designs, and ultimately affect launch availability . The objective of this study is to physically simulate predicted oscillation envelopes identified by analysis. and conduct a Human Factors Analysis to assess the ability to carry out essential Upper Stage (US) ground operator tasks based on predicted vehicle motion.

Atencio, Laura Ashley↗

Measuring Global Surface Pressures on a Circulation Control Concept Using Pressure Sensitive Paint

This report will present the results obtained from the Pressure Sensitive Paint (PSP) technique on a circulation control concept model. This test was conducted at the National Transonic Facility (NTF) at the NASA Langley Research Center. PSP was collected on the upper wing surface while the facility was operating in cryogenic mode at 227 K (-50 oF). The test envelope for the PSP portion included Mach numbers from 0.7 to 0.8 with angle of attack varying between 0 and 8 degrees and a total pressure of approximately 168 kPa (24.4 psi), resulting in a chord Reynolds number of approximately 15 million. While the PSP results did exhibit high levels of noise in certain conditions (where the oxygen content of the flow was very small), some conditions provided good correlation between the PSP and pressure taps, showing the ability of the PSP technique. This work also served as a risk reduction opportunity for future testing in cryogenic conditions at the NTF.

Watkins, Anthony N.↗

Innovative Flow Control Concepts for Drag Reduction

This paper highlights the technology development of two flow control concepts for aircraft drag reduction. The NASA Environmentally Responsible Aviation (ERA) project worked with Boeing to demonstrate these two concepts on a specially outfitted Boeing 757 ecoDemonstrator during the spring of 2015. The first flow control concept used Active Flow Control (AFC) to delay flow separation on a highly deflected rudder and increase the side force that it generates. This may enable a smaller vertical tail to provide the control authority needed in the event of an engine failure during takeoff and landing, while still operating in a conventional manner over the rest of the flight envelope. Thirty-one sweeping jet AFC actuators were installed and successfully flight-tested on the vertical tail of the 757 ecoDemonstrator. Pilot feedback, flow cone visualization, and analysis of the flight test data confirmed that the AFC is effective, as a smoother flight and enhanced rudder control authority were reported. The second flow control concept is the Insect Accretion Mitigation (IAM) innovation where surfaces were engineered to mitigate insect residue adhesion on a wing's leading edge. This is necessary because something as small as an insect residue on the leading edge of a laminar flow wing design can cause turbulent wedges that interrupt laminar flow, resulting in an increase in drag and fuel use. Several non-stick coatings were developed by NASA and applied to panels that were mounted on the leading edge of the wing of the 757 ecoDemonstrator. The performance of the coated surfaces was measured and validated by the reduction in the number of bug adhesions relative to uncoated control panels flown simultaneously. Both flow control concepts (i.e., sweeping jet actuators and non-stick coatings) for drag reduction were the culmination of several years of development, from wind tunnel tests to flight tests, and produced valuable data for the advancement of modern aircraft designs. The ERA systems analysis studies performed by NASA indicated that AFC-enhanced vertical tail could produce approximately 0.9% drag reduction for a large twin aisle aircraft and IAM coatings could enable approximately 1.2% drag reduction recovery for a potential total drag reduction of approximately 3.3% for a single aisle aircraft with a natural laminar flow (NLF) wing design.

Lin, John C.↗

Active Flow Control (AFC) and Insect Accretion and Mitigation (IAM) System Design and Integration on the Boeing 757 ecoDemonstrator

This paper presents a systems overview of how the Boeing and NASA team designed, analyzed, fabricated, and integrated the Active Flow Control (AFC) technology and Insect Accretion Mitigation (IAM) systems on the Boeing 757 ecoDemonstrator. The NASA Environmentally Responsible Aviation (ERA) project partnered with Boeing to demonstrate these two technology systems on a specially outfitted Boeing 757 ecoDemonstrator during the spring of 2015. The AFC system demonstrated attenuation of flow separation on a highly deflected rudder and increased the side force generated. This AFC system may enable a smaller vertical tail to provide the control authority needed in the event of an engine failure during takeoff while still operating in a conventional manner over the rest of the flight envelope. The AFC system consisted of ducting to obtain air from the Auxiliary Power Unit (APU), a control valve to modulate the system mass flow, a heat exchanger to lower the APU air temperature, and additional ducting to deliver the air to the AFC actuators located on the vertical tail. The IAM system demonstrated how to mitigate insect residue adhesion on a wing's leading edge. Something as small as insect residue on a leading edge can cause turbulent wedges that interrupt laminar flow, resulting in an increase in drag and fuel use. The IAM system consisted of NASA developed Engineered Surfaces (ES) which were thin aluminum sheet substrate panels with coatings applied to the exterior. These ES were installed on slats 8 and 9 on the right wing of the 757 ecoDemonstrator. They were designed to support panel removal and installation in one crew shift. Each slat accommodated 4 panels. Both the AFC and IAM flight test were the culmination of several years of development and produced valuable data for the advancement of modern aircraft designs.

Alexander, Michael G.↗

Global Aerodynamic Modeling Using Automated Local Model Networks in Real Time

A novel method is presented for automated real-time global aerodynamic modeling using local model networks, known as Smoothed Partitioning with Localized Trees in Real Time (SPLITR), as part of NASA’s Learn-to-Fly technology development initiative. The global nonlinear aerodynamics are partitioned into several local regions known as cells, with the dimension, location, and timing of each partition automatically selected based on a residual characterization procedure, under the constraints of real-time operation. Regression trees represent the successive partitioning of the global flight envelope and describe the evolution of the cell structure. Recursive equation-error least-squares parameter estimation in the time domain is used to estimate a model that represents the local aerodynamics in each region, so that it can be updated independently with non-contiguous data in the range of each cell over time. A weighted superposition of these piecewise local models across the flight envelope forms a global nonlinear model that also accurately captures the local aerodynamics. The SPLITR approach is demonstrated using both simulation and flight data, and the results are analyzed in terms of model predictive capabilities as well as interpretability. The results show that SPLITR can be used to automatically partition complex nonlinear aerodynamic behavior, produce an accurate model, and provide valuable physical insight into the local and global aerodynamics.

Weinstein, Rose↗

What is involved in radiation protection at accelerator facilities?

Radiation protection for accelerator facilities involves a range of actions to operate the facility within safe boundaries (often called an accelerator safety envelope) and it starts from the very early stage of facility development. Each facility will establish fundamental safety principles, requirements, and measures to control the radiation exposure to people and the release of radioactive material to the environment.

61 RADIATION PROTECTION AND DOSIMETRY↗

Force reflecting hand controller

A universal input device for interfacing a human operator with a slave machine such as a robot or the like includes a plurality of serially connected mechanical links extending from a base. A handgrip is connected to the mechanical links distal from the base such that a human operator may grasp the handgrip and control the position thereof relative to the base through the mechanical links. A plurality of rotary joints is arranged to connect the mechanical links together to provide at least three translational degrees of freedom and at least three rotational degrees of freedom of motion of the handgrip relative to the base. A cable and pulley assembly for each joint is connected to a corresponding motor for transmitting forces from the slave machine to the handgrip to provide kinesthetic feedback to the operator and for producing control signals that may be transmitted from the handgrip to the slave machine. The device gives excellent kinesthetic feedback, high-fidelity force/torque feedback, a kinematically simple structure, mechanically decoupled motion in all six degrees of freedom, and zero backlash. The device also has a much larger work envelope, greater stiffness and responsiveness, smaller stowage volume, and better overlap of the human operator's range of motion than previous designs.

Mcaffee, Douglas A.↗

Risk Considerations of Transitioning CO2-EOR Field to CO2 storage Field: Case Study

In the United States (U.S.), carbon dioxide (CO2) injection wells at EOR sites are currently regulated as Class II wells under the U.S. Environmental Protection Agency’s (EPA) Underground Injection Control (UIC) program while dedicated geological CO2 storage (GCS) wells are considered Class VI wells. A CO2-EOR facility considering a transitioning from tertiary oil recovery to injecting CO2 for the primary purpose of long-term storage is required to obtain a Class VI permit where this transition poses an increased risk to underground sources of drinking water. This study considers how transitioning operations from CO2-EOR to storage can impact reservoir plume and pressure transient in the storage envelope, and how these changes could impact area of review and potential unwanted fluid migration. We developed a case study to assess subsurface response and leakage risks associated with a representative, hypothetical operation in a carbonate reservoir. This reservoir transitions from tertiary hydrocarbon recovery to dedicated GCS. Reservoir simulations were run for a set of credible CO2-EOR scenarios to estimate distributions of fluids phases and pressures throughout the model domain after CO2 flooding as well as forecasting the behavior of the reservoir after the transition to a dedicated storage phase. The evolutions from all simulated scenarios were used as the basis for leakage risk quantification using the National Risk Assessment Partnership’s Open-Source Integrated Assessment Model (NRAP-Open-IAM) with a novel reduced-order model to estimate time-dependent leakage of CO2, brine, and hydrocarbon fluids through potentially leaky wells. Results include a description of reservoir response, an estimate of the areal extent that could potentially be impacted by leakage to underground sources of drinking water, and estimates of the magnitude of potential leakage. Considerations for dedicated storage injection well selection, injectivity, and injection scheme performance and potential leakage risk are presented, with implications for risk assessment of well transition discussed. This study presents a risk-based workflow for the Class II to Class VI well transition. Integrating credible numerical simulation of viable CO2-EOR to dedicated CO2 storage with quantitative risk assessment tools, such as the NRAP-Open-IAM, will provide a valuable means to devise operational scenarios and inform decision-making related to storage benefit, leakage risk, and liability. Presented at the SPE/AAPG/SEG Carbon Capture Utilization and Storage Conference in Houston, TX, March 11-13, 2024.

Liu, Guoxiang↗

Cost Analysis of Simple Phase Change Material-Enhanced Building Envelopes in Southern U.S. Climates

Traditional thermal designs of building envelope assemblies are based on static energy flows, yet building envelopes are subject to varying environmental conditions. This mismatch between the steady-state principles and their dynamic operation can decrease thermal efficiency. Design work supporting the development of low-energy houses showed that conventional insulations may not always be the most cost effective solution to improvement envelope thermal performance. PCM-enhanced building envelopes that simultaneously reduce the total cooling loads and shift the peak-hour loads are the focus of this report.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Cost Analysis of Simple Phase Change Material-Enhanced Building Envelopes in Southern U.S. Climates

Traditional thermal designs of building envelope assemblies are based on static energy flows, yet building envelopes are subject to varying environmental conditions. This mismatch between the steady-state principles and their dynamic operation can decrease thermal efficiency. Design work supporting the development of low-energy houses showed that conventional insulations may not always be the most cost effective solution to improvement envelope thermal performance. PCM-enhanced building envelopes that simultaneously reduce the total cooling loads and shift the peak-hour loads are the focus of this report.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

P2P: Point Cloud to Panel Layout Optimization

Building envelope retrofits, despite their benefits on enhancing energy efficiency, progress slowly due to high operating costs. Overclad panelized systems present an attractive solution to make retrofits affordable and easy to install. However, several stages of the retrofit process remain disconnected, suboptimal, and require significant human intervention. This study aims to bridge the gap between digital twin generation and overclad panel installation by automating the design of an optimal panel layout directly from a building envelope point cloud. In this end-to-end approach, the dimensional twin is generated by segmenting the facade point cloud. The facade then undergoes a three-step process to generate an optimized panel layout for integration with automated placement systems.

Philips, Nisha Deborah [ORNL]↗

CisLunar Habitat Internal Architecture Design Criteria

BACKGROUND: In preparation for human exploration to Mars, there is a need to define the development and test program that will validate deep space operations and systems. In that context, a Proving Grounds CisLunar habitat spacecraft is being defined as the next step towards this goal. This spacecraft will operate differently from the ISS or other spacecraft in human history. The performance envelope of this spacecraft (mass, volume, power, specifications, etc.) is being defined by the Future Capabilities Study Team. This team has recognized the need for a human-centered approach for the internal architecture of this spacecraft and has commissioned a CisLunar Phase-1 Habitat Internal Architecture Study Team to develop a NASA reference configuration, providing the Agency with a "smart buyer" approach for future acquisition. THE CISLUNAR HABITAT INTERNAL ARCHITECTURE STUDY: Overall, the CisLunar Habitat Internal Architecture study will address the most significant questions and risks in the current CisLunar architecture, habitation, and operations concept development. This effort is achieved through definition of design criteria, evaluation criteria and process, design of the CisLunar Habitat Phase-1 internal architecture, and the development and fabrication of internal architecture concepts combined with rigorous and methodical Human-in-the-Loop (HITL) evaluations and testing of the conceptual innovations in a controlled test environment. The vision of the CisLunar Habitat Internal Architecture Study is to design, build, and test a CisLunar Phase-1 Habitat Internal Architecture that will be used for habitation (e.g. habitability and human factors) evaluations. The evaluations will mature CisLunar habitat evaluation tools, guidelines, and standards, and will interface with other projects such as the Advanced Exploration Systems (AES) Program integrated Power, Avionics, Software (iPAS), and Logistics for integrated human-in-the-loop testing. The mission of the CisLunar Habitat Internal Architecture Study is to become a forcing function to establish a common understanding of CisLunar Phase-1 Habitation Internal Architecture design criteria, processes, and tools. The scope of the CisLunar Habitat Internal Architecture study is to design, develop, demonstrate, and evaluate a Phase-1 CisLunar Habitat common module internal architecture based on design criteria agreed to by NASA, the International Partners, and Commercial Exploration teams. This task is to define the CisLunar Phase-1 Internal Architecture Government Reference Design, assist NASA in becoming a "smart buyer" for Phase-1 Habitat Concepts, and ultimately to derive standards and requirements from the Internal Architecture Design Process. The first step was to define a Habitat Internal Architecture Design Criteria and create a structured philosophy to be used by design teams as a filter by which critical aspects of consideration would be identified for the purpose of organizing and utilizing interior spaces. With design criteria in place, the team will develop a series of iterative internal architecture concept designs which will be assessed by means of an evaluation criteria and process. These assessments will successively drive and refine the design, leading to the combination and down-selection of design concepts. A single refined reference design configuration will be developed into in a medium-to-high fidelity mockup. A multi-day human-in-the-loop mission test will fully evaluate the reference design and validate its configuration. Lessons learned from the design and evaluation will enable the team to identify appropriate standards for Phase-1 CisLunar Habitat Internal Architecture and will enable NASA to develop derived requirements in support of maturing CisLunar Habitation capabilities. This paper will describe the criteria definition process, workshop event, and resulting CisLunar Phase-1 Habitat Internal Architecture Design Criteria.

Jones, R.↗

Operations Strategies for the Mars Exploration Rovers During the 2007 Martian Global Dust Storm

In June and July 2007 Mars experienced a dust storm that grew to envelop all but the polar latitudes of the planet. This dust storm was the first global dust storm to occur while the twin Mars Exploration Rovers (MER) began surface operations. It is estimated that the dust in the atmosphere prevented over 99.6% of direct sunlight from reaching the surface at the peak of the storm. Data collected indicated that solar array energy output was reduced to approximately 15% of maximum. The reduction in insolation and energy output posed the greatest risk of ending the mission for both rovers at that time.

Seibert, Michael↗

Non-Toxic Orbital Maneuvering System Engine Development

Recent results using the Aestus engine operated with LOx/ethanol propellant are presented. An experimental program at Rocketdyne Propulsion and Power is underway to adapt this engine for the Boeing Reusable Space Systems Division non-toxic Orbital Maneuvering System/Reaction control System (OMS/RCS) system. Daimler-Chrysler Aerospace designed the Aestus as an nitrogen tetroxide/monomethyl hydrazine (NTO/MMH) upper-stage engine for the Ariane 5. The non-toxic OMS/RCS system's preliminary design requires a LOx/ethanol (O2/C2H5OH) engine that operates with a mixture ratio of 1.8, a specific impulse of 323 seconds, and fits within the original OMS design envelope. This paper describes current efforts to meet these requirements including, investigating engine performance using LOx/ethanol, developing the en-ine system sizing package, and meeting the vehicle operation parameters. Data from hot-fire testing are also presented and discussed.

Green, Christopher↗

Reach Envelope and Field of Vision Quantification in Mark III Space Suit Using Delaunay Triangulation

The Science Crew Operations and Utility Testbed (SCOUT) project is focused on the development of a rover vehicle that can be utilized by two crewmembers during extra vehicular activities (EVAs) on the moon and Mars. The current SCOUT vehicle can transport two suited astronauts riding in open cockpit seats. Among the aspects currently being developed is the cockpit design and layout. This process includes the identification of possible locations for a socket to which a crewmember could connect a portable life support system (PLSS) for recharging power, air, and cooling while seated in the vehicle. The spaces in which controls and connectors may be situated within the vehicle are constrained by the reach and vision capabilities of the suited crewmembers. Accordingly, quantification of the volumes within which suited crewmembers can both see and reach relative to the vehicle represents important information during the design process.

Abercromby, Andrew F. J.↗

Dependence of the gyrotron efficiency on the azimuthal index of non-symmetric modes

Development of MW-class gyrotrons for future controlled fusion reactors requires careful analysis of the stability of high efficiency operation in very high-order modes. In the present paper, this problem is analyzed in the framework of the non-stationary self-consistent theory of gyrotrons. Two approaches are used: the one based on the wave envelope representation of the resonator field and the second one based on representation of this field as a superposition of eigenmodes, whose fields are determined by a self-consistent set of equations. It is shown that at relatively low beam currents, when the maximum efficiency can be realized in the regime of soft self-excitation, the operation in the desired mode is stable even in the case of a very dense spectrum of competing modes. At higher currents, the maximum efficiency can be realized in the regimes with hard self-excitation; here the operation in the desired mode can be unstable because of the presence of some competing modes with low start currents. Two 170 GHz European gyrotrons for the international thermonuclear experimental reactor are considered as examples. In the first one, which is the 2 MW gyrotron with a coaxial resonator, the stability of operation in a chosen TE{sub 34,19}-mode in the presence of two sideband modes with almost equidistant spectrum is analyzed and the region of magnetic fields in which the oscillations of the central mode are stable is determined. The operation of the second gyrotron, which is the 1 MW gyrotron with a cylindrical cavity currently under development in Europe, is studied by using the wave envelope approach. It is shown that high efficiency operation of this gyrotron in the TE{sub 32,9}-mode should be stable.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗