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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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NASA NTRS2005

Survey of Command Execution Systems for NASA Spacecraft and Robots

NASA spacecraft and robots operate at long distances from Earth Command sequences generated manually, or by automated planners on Earth, must eventually be executed autonomously onboard the spacecraft or robot. Software systems that execute commands onboard are known variously as execution systems, virtual machines, or sequence engines. Every robotic system requires some sort of execution system, but the level of autonomy and type of control they are designed for varies greatly. This paper presents a survey of execution systems with a focus on systems relevant to NASA missions.

Verma, Vandi↗

NASA NTRS2007

Space Qualification Issues in Acousto-optic and Electro-optic Devices

Satellite and space-based applications of photonic devices and systems require operational reliability in the harsh environment of space for extended periods of time. This in turn requires every component of the systems and their packaging to meet space qualifications. Acousto- and electro-optical devices form the major components of many current space based optical systems, which is the focus of this paper. The major space qualification issues are related to: mechanical stability, thermal effects and operation of the devices in the naturally occurring space radiation environment. This paper will discuss acousto- and electro-optic materials and devices with respect to their stability against mechanical vibrations, thermal cycling in operating and non-operating conditions and device responses to space ionizing and displacement radiation effects. Selection of suitable materials and packaging to meet space qualification criteria will also be discussed. Finally, a general roadmap for production and testing of acousto- and electro-optic devices will be discussed.

Prasad, Narasimha S.↗

NASA NTRS2014

AFC-Enabled Vertical Tail System Integration Study

This document serves as the final report for the SMAAART AFC-Enabled Vertical Tail System Integration Study. Included are the ground rule assumptions which have gone into the study, layouts of the baseline and AFC-enabled configurations, critical sizing information, system requirements and architectures, and assumed system properties that result in an NPV assessment of the two candidate AFC technologies.

Mooney, Helen P.↗

NASA NTRS2017

Hercules Single-Stage Reusable Vehicle (HSRV) Operating Base

Conceptual design for the layout of lunar-planetary surface support systems remains an important area needing further master planning. This paper explores a structured approach to organize the layout of a Mars-based site equipped for routinely flying a human-scale reusable taxi system. The proposed Hercules Transportation System requires a surface support capability to sustain its routine, affordable, and dependable operation. The approach organizes a conceptual Hercules operating base through functional station sets. The station set approach will allow follow-on work to trade design approaches and consider technologies for more efficient flow of material, energy, and information at future Mars bases and settlements. The station set requirements at a Mars site point to specific capabilities needed. By drawing from specific Hercules design characteristics, the technology requirements for surface-based systems will come into greater focus. This paper begins a comprehensive process for documenting functional needs, architectural design methods, and analysis techniques necessary for follow-on concept studies.

Surface Support Architectur↗

NASA NTRSDate not supplied

In Situ Resource Utilization (ISRU) Envisioned Future Priorities

The National Aeronautics and Space Administration (NASA) of the United States of America (US) has initiated the Artemis Moon to Mars program to send astronauts (the first woman and person of color) back to the lunar surface, create a sustainable human lunar exploration program, and lead the first human exploration mission to the Mars surface in the 2030’s. A major objective of this program is to characterize the resources that exist on the Moon and Mars, and learn how to utilize them for sustained and affordable exploration. Commonly known as In Situ Resource Utilization (ISRU), the search for, acquisition, and processing of resources in space has the potential to greatly reduce the dependency on transporting mission consumables and infrastructure from Earth, thereby reducing mission costs, risks, and dependency on Earth. Through the extraction and processing of resources into mission commodities such as rocket propellants, life support consumables, and fuel cell reactants, ISRU enhances and evolves the cis-lunar, lander, and surface transportation systems required for human exploration; expanding and ehancing HOW humans get to, explore, and return from the Moon. Through the extraction and processing of resources into metals, silicon, and other manufacturing and construction feedstock, ISRU enhances and allows for the expansion of critical infrastructure through in situ manufacturing and construction capabilities needed for WHAT humans do on the Moon and in cis-lunar space. Because of this, ISRU supports and enables commercial involvement beyond NASA and governmental agencies by both lowering the cost of sustained transportation to/from/on the Moon as well as supporting the market required for needing these transportation systems. To achieve this vision, NASA’s Space Technology Mission Directorate (STMD) ensures the coordinated development of ISRU and other critical space and surface infrastructure elements such as propulsion, power, manufacturing, construction, and robotics through the Strategic Technology Architecture Roundtable (STAR) process. Through STAR, an integrated framework and process has been created allowing for capabilities and technologies to be linked and assessed, gaps to be identified, specifications and metrics to be established, and provide a means to prioritize and implement technology development and missions. For lunar ISRU, three primary areas of development have been initiated, (1) understanding, mapping, extracting, and processing water and other volatiles found in polar permanently shadowed regions (PSRs), (2) methods, technologies to extract oxygen from regolith, and (3) methods, technologies, and use cases for metals, silicon, and other feedstock commodities extracted and produced from lunar resources. This presentation will briefly discuss the STAR process and elaborate on the current status and future plans for ISRU development, demonstration, and architecture implementation of NASA’s Envisioned Future Priorities plan for ISRU.

In Situ Resource Utilization↗

NASA NTRS2007

Ares I Crew Launch Vehicle Project: Forward Plan to Preliminary Design Review

The Exploration Launch Projects Office, located at NASA's Marshall Space Flight Center, conducted the Ares I Crew Launch Vehicle System Requirements Review (SRR) at the end of 2006, a mere year after the project team was assembled. In Ares' first year, extensive trade studies and evaluations were conducted to refine the design initially recommended by the Exploration Systems Architecture Study, conceptual designs were analyzed for fitness, and the contractual framework was assembled to enable a development effort unparalleled in American space flight since the Space Shuttle. Now, the project turns its focus to the Preliminary Design Review (PDR), scheduled for 2008. Taking into consideration the findings of the SRR, the design of the Ares I is being tightened and refined to meet the operability, reliability, and affordability goals outlined by the Constellation Program. As directed in NASA Procedure and Regulation (NPR) 7123, NASA Systems Engineering Procedural Requirements, the Ares I SRR examined "the functional and performance requirements defined for the system and the preliminary program or project plan and ensures that the requirements and the selected concept will satisfy the mission." The SRR was conducted to ensure the system- and element-level design and interface requirements are defined prior to proceeding into the project's design phase. The Exploration Launch Projects Control Board convened on December 19,2006, and accepted the findings of the SRR and the go-forward plan proceeding to PDR. Based upon these findings, the Ares project believes that operability must drive the vehicle's design, and that a number of design challenges, including system mass and reliability, must be addressed as part of the progress to PDR.

Dumbacher, Daniel L.↗

NASA NTRS2021

Role of Cyber-Physical Testing in Developing Resilient Extraterrestrial Habitats

Extraterrestrial long-term habitat systems (henceforth referred to as habitat systems) require groundbreaking technological advances to overcome the extreme demands introduced by isolation and challenging environments. A habitat system must operate as intended under continuous disruptive conditions. Designing for the demands that challenging environments will place on habitat systems (e.g., wild temperature fluctuations, galactic cosmic rays, destructive dust, meteoroid impacts, vibrations, and solar particle events) represents one of the greatest challenges in this endeavor. This engineering problem necessitates that we design and manage habitat systems to be resilient. System resilience requires a comprehensive approach that accounts for disruptions through the design process and adapts to them in operation. As the habitat system evolves—growing in physical size, complexity, population, and connectivity—and diversifies in operations, it must continue to be safe and resilient. In this endeavor, we should take advantage of lessons learned in developing civil infrastructure responsive to catastrophic natural hazards, autonomous robotics platforms, smart buildings, cyber-physical testing, complex systems, and diagnostics and prognostics for intelligent health management. This study highlights the importance of system resilience and cyber-physical testing to address the grand challenge of developing habitat systems.

Public health and safety↗

NASA NTRS2003

Software Requirements Analysis as Fault Predictor

Waiting until the integration and system test phase to discover errors leads to more costly rework than resolving those same errors earlier in the lifecycle. Costs increase even more significantly once a software system has become operational. WE can assess the quality of system requirements, but do little to correlate this information either to system assurance activities or long-term reliability projections - both of which remain unclear and anecdotal. Extending earlier work on requirements accomplished by the ARM tool, measuring requirements quality information against code complexity and test data for the same system may be used to predict specific software modules containing high impact or deeply embedded faults now escaping in operational systems. Such knowledge would lead to more effective and efficient test programs. It may enable insight into whether a program should be maintained or started over.

Wallace, Dolores↗

NASA NTRS2007

Smart Sensor Node Development, Testing and Implementation for Rocket Propulsion Systems

Successful design and implementation of an Integrated System Health Management (ISHM) approach for rocket propulsion systems requires the capability improve the reliability of complex systems by detecting and diagnosing problems. One of the critical elements in the ISHM is an intelligent sensor node for data acquisition that meets specific requirements for rocket motor testing including accuracy, sample rate and size/weight. Traditional data acquisition systems are calibrated in a controlled environment and guaranteed to perform bounded by their tested conditions. In a real world ISHM system, the data acquisition and signal conditioning needs to function in an uncontrolled environment. Development and testing of this sensor node focuses on a design with the ability to self check in order to extend calibration times, report internal faults and drifts and notify the overall system when the data acquisition is not performing as it should. All of this will be designed within a system that is flexible, requiring little re-design to be deployed on a wide variety of systems. Progress in this design and initial testing of prototype units will be reported.

Mengers, Timothy R.↗

NASA NTRS1984

Detailed Performance Calculations: Goddard Group, Appendix D

Two systems were described. The first used polarization to reduce scattered solar flux, the principal source of noise. The second used a narrowband detector and a different excitation wavelength. The results, which consider these systems, were presented emphasizing anticipated technology improvements because the analysis for each system required estimates of critical parameter even though each system would use existing technology. For the first, the information about the degree of polarization of the scattered solar flux was not measured but was estimated as 60 percent for viewing straight up with a solar zenith angle of 75 percent at sea level. The expected performance of this system therefore depends on the reliability of this estimate. For the second system, two estimates were required. First, the expected throughput of a Fabry-Perot interferometer operating at 309 nm, based on the performance exhibited by similar instruments working at other wavelengths, was estimated to be 3 percent. Second, the fluorescence efficiency of the proposed OH lines was estimated as 0.00004, since these quantities were not measured to date.

Source record↗

NASA NTRS2009

Altair Lander Life Support: Requirement Analysis Cycles 1 and 2

Life support systems are a critical part of human exploration beyond low earth orbit. NASA s Altair Lunar Lander has unique missions to perform and will need a unique life support system to complete them. Initial work demonstrated a feasible minimally-functional Lander design. This work was completed in Design Analysis Cycles (DAC) 1, 2, and 3 were reported in a previous paper. On October 21, 2008, the Altair project completed the Mission Concept Review (MCR), moving the project into Phase A. In Phase A activities, the project is preparing for the System Requirements Review (SRR). Altair has conducted two Requirements Analysis Cycles (RACs) to begin this work. During this time, the life support team must examine the Altair mission concepts, Constellation Program level requirements, and interfaces with other vehicles and spacesuits to derive the right set of requirements for the new vehicle. The minimum functionality design meets some of these requirements already and can be easily adapted to meet others. But Altair must identify which will be more costly in mass, power, or other resources to meet. These especially costly requirements must be analyzed carefully to be sure they are truly necessary, and are the best way of explaining and meeting the true need. If they are necessary and clear, they become important mass threats to track at the vehicle level. If they are not clear or do not seem necessary to all stakeholders, Altair must work to redefine them or push back on the requirements writers. Additionally, the life support team is evaluating new technologies to see if they are more effective than the existing baseline design at performing necessary functions in Altair s life support system.

Anderson, Molly↗

NASA NTRS2010

Altair Lander Life Support: Requirements Analysis Cycles 1 and 2

Life support systems are a critical part of human exploration beyond low earth orbit. NASA's Altair Lunar Lander has unique missions to perform and will need a unique life support system to complete them. Initial work demonstrated a feasible minimally -functional Lander design. This work was completed in Design Analysis Cycles (DAC) 1, 2, and 3 were reported in a previous paper'. On October 21, 2008, the Altair project completed the Mission Concept Review (MCR), moving the project into Phase A. In Phase A activities, the project is preparing for the System Requirements Review (SRR). Altair has conducted two Requirements Analysis Cycles (RACs) to begin this work. During this time, the life support team must examine the Altair mission concepts, Constellation Program level requirements, and interfaces with other vehicles and spacesuits to derive the right set of requirements for the new vehicle. The minimum functionality design meets some of these requirements already and can be easily adapted to meet others. But Altair must identify which will be more costly in mass, power, or other resources to meet. These especially costly requirements must be analyzed carefully to be sure they are truly necessary, and are the best way of explaining and meeting the true need. If they are necessary and clear, they become important mass threats to track at the vehicle level. If they are not clear or do not seem necessary to all stakeholders, Altair must work to redefine them or push back on the requirements writers. Additionally, the life support team is evaluating new technologies to see if they are more effective than the existing baseline design at performing necessary functions in Altair's life support system.

Anderson, Molly↗

NASA NTRS1989

Software reuse issues affecting AdaNET

The AdaNet program is reviewing its long-term goals and strategies. A significant concern is whether current AdaNet plans adequately address the major strategic issues of software reuse technology. The major reuse issues of providing AdaNet services that should be addressed as part of future AdaNet development are identified and reviewed. Before significant development proceeds, a plan should be developed to resolve the aforementioned issues. This plan should also specify a detailed approach to develop AdaNet. A three phased strategy is recommended. The first phase would consist of requirements analysis and produce an AdaNet system requirements specification. It would consider the requirements of AdaNet in terms of mission needs, commercial realities, and administrative policies affecting development, and the experience of AdaNet and other projects promoting the transfer software engineering technology. Specifically, requirements analysis would be performed to better understand the requirements for AdaNet functions. The second phase would provide a detailed design of the system. The AdaNet should be designed with emphasis on the use of existing technology readily available to the AdaNet program. A number of reuse products are available upon which AdaNet could be based. This would significantly reduce the risk and cost of providing an AdaNet system. Once a design was developed, implementation would proceed in the third phase.

Mcbride, John G.↗

NASA NTRS1989

Viscosity measurements at high temperature and high pressure: A novel technique

The extensive numerical modelling of transport phenomena was performed for the melt growth of mercury cadmium telluride. To increase the fidelity of modelling the kinematic viscosity of liquid Hg(1-x)Cd(x)Te was determined at various compositions in the range of x between 0 and 0.2 and at temperatures around and below the respective melting point. The phase diagram of Hg(1-x)Cd(x)Te shows that for this range the melting point varies from 670 C for pure HgTe to 790 C at x=0.2. The vapor pressure above the melt varies correspondingly from 15 to about 40 atm. Hence, the measurement of viscosities in this system requires a technique that allows for combinations of high temperatures and pressures. In addition, a closed isothermal system is required. The high pressure melt container must also be inert to molten Hg(1-x)Cd(x)Te to avoid possible errors from contamination of the liquid. A novel technique that largely circumvents the above experimental problems is described. Its theory is also presented.

Jin, Wei-Qing↗

NASA NTRS1992

Engine system assessment study using Martian propellants

A top-level feasibility study was conducted that identified and characterized promising chemical propulsion system designs which use two or more of the following propellant combinations: LOX/H2, LOX/CH4, and LOX/CO. The engine systems examined emphasized the usage of common subsystem/component hardware where possible. In support of this study, numerous mission scenarios were characterized that used various combinations of Earth, lunar, and Mars propellants to establish engine system requirements to assess the promising engine system design concept examined, and to determine overall exploration leverage of such systems compared to state-of-the-art cryogenic (LOX/H2) propulsion systems. Initially in the study, critical propulsion system technologies were assessed. Candidate expander and gas generator cycle LOX/H2/CO, LOX/H2/CH4, and LOX/CO/CH4 engine system designs were parametrically evaluated. From this evaluation baseline, tripropellant Mars Transfer Vehicle (MTV) LOX cooled and bipropellant Lunar Excursion Vehicle (LEV) and Mars Excursion Vehicle (MEV) engine systems were identified. Representative tankage designs for a MTV were also investigated. Re-evaluation of the missions using the baseline engine design showed that in general the slightly lower performance, smaller, lower weight gas generator cycle-based engines required less overall mission Mars and in situ propellant production (ISPP) infrastructure support compared to the larger, heavier, higher performing expander cycle engine systems.

Pelaccio, Dennis↗

NASA NTRS2017

Control Design for an Advanced Geared Turbofan Engine

This paper describes the design process for the control system of an advanced geared turbofan engine. This process is applied to a simulation that is representative of a 30,000 lbf thrust class concept engine with two main spools, ultra-high bypass ratio, and a variable area fan nozzle. Control system requirements constrain the non-linear engine model as it operates throughout its flight envelope of sea level to 40,000 ft and from 0 to 0.8 Mach. The control architecture selected for this project was developed from literature and reflects a configuration that utilizes a proportional integral controller integrated with sets of limiters that enable the engine to operate safely throughout its flight envelope. Simulation results show the overall system meets performance requirements without exceeding system operational limits.

aerothermodynamics↗

NASA NTRS2017

Control Design for an Advanced Geared Turbofan Engine

gas path dynamics↗

NASA NTRS1975

Flight Performance of Skylab Attitude and Pointing Control System

In 1967 a paper at the AIAA Guidance, Control and Flight Dynamics Conference in Huntsville, Ala. presented for the first time the prot)osed SKYLAB Attitude and Pointing Control System (APCS) The system requirements, Apollo Telescope Mount (ATM) configuration, control philosophy, and operational modes were presented and the APCS described. The Initial mission and system design requirements changed during the period of time before the SKYLAB was launched. This paper will review the Initial and final APCS requirements and goals and their relationship. The actual flight mission (and Its alterations during the flight) and known achieved APCS performance will then be presented. SKYLAB was a tremendous success in furthering man's scientific knowledge; but perhaps SKYLAB will be remembered more for the anomalies and the efforts undertaken to solve them. On May 14, 1973, the unmanned SKYLAB Orbital Workshop (OWS) was launched from Cape Kennedy. Serious hardware failures began to occur during ascent through the atmosphere and their spectre continued to haunt both the astronauts and their ground based support team. Nor were these the only surprises affecting the design and operation of the APCS. Mission requirements for pointing to various stellar targets and to nadir for earth resources experiments were added after the hardware was designed. The chance appearance of comet Kohoutek during the SKYLAB operational life-time caused NASA to add comet observation to the mission requirements and to adjust the time when the third crew would man the SKYLAB. The development of new procedures and software for the opportunity to observe this visitor to our solar system is described.

Chubb, W. B.↗