SEARCH · Engineering Papers
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.
Survey of human operator response mechanisms, and development of visual-auditory display device to increase operator response speed, frequency, and flexibility
NASA's new exploration initiative will again take humans beyond low Earth orbit, to the moon, and into deep space. The space agency is developing a new fleet of launch vehicles that will fulfill the national goals of replacing the Space Shuttle fleet, completing the International Space Station, establishing a permanent outpost on the moon, and eventually traveling to Mars. Separate crew and cargo vehicles emerged from mission architecture studies - the Ares I to carry the Orion crew exploration vehicle and its crew of4 to 6 astronauts, and the Ares V to carry the Altair lunar lander or other supplies to support future exploration missions. (Figure 1) These vehicles will be designed to be safe, affordable, sustainable, reliable, operable with the safety, reliability, flexibility, and operability to serve this nation's manned and unmanned exploration programs for the coming decades. This paper discusses recent and current progress on the Ares V and planned future activities.
In the early days of the International Space Station (ISS) program, and as the organization structure was being internationally agreed upon and documented, one of the principal tenets of the science program was to allow customer-friendly operations. One important aspect of this was to allow payload developers and principle investigators the flexibility to operate their experiments from either their home sites or distributed telescience centers. This telescience concept was developed such that investigators had several options for ISS utilization support. They could operate from their home site, the closest telescience center, or use the payload operations facilities at the Marshall Space Flight Center in Huntsville, Alabama. The Payload Operations Integration Center (POIC) processes and structures were put into place to allow these different options to its customers, while at the same time maintain its centralized authority over NASA payload operations and integration. For a long duration space program with many scientists, researchers, and universities expected to participate, it was imperative that the program structure be in place to successfully facilitate this concept of telescience support. From a payload control center perspective, payload science operations require two major elements in order to make telescience successful within the scope of the ISS program. The first element is decentralized control which allows the remote participants the freedom and flexibility to operate their payloads within their scope of authority. The second element is a strong ground infrastructure, which includes voice communications, video, telemetry, and commanding between the POIC and the payload remote site. Both of these elements are important to telescience success, and both must be balanced by the ISS program s documented requirements for POIC to maintain its authority as an integration and control center. This paper describes both elements of distributed payload operations and discusses the benefits and drawbacks.
The InSAR Scientific Computing Environment (ISCE) was first developed under the NASA Advanced Information Systems Technology as a flexible, extensible object-oriented framework for Interferometric Synthetic Aperture Radar (InSAR) processing. The ISCE framework uses Python 3 at the workflow level, controlling modules of compiled code for functional processing, and managing inputs, outputs, and other flow control services. The currently released version, called ISCE 2.1, is distributed to the research community through the Western North America InSAR Consortium under a research license. The ISCE team is working on the next generation of the code in order to prepare for the NASAISRO SAR (NISAR) mission operational processing. Innovations in this code include augmentation or conversion of the custom Python framework elements in ISCE with the Pyre framework, new workflows for interferometric and polarimetric stack processing, a more intuitive and graphically based user interface, and flow control for hybrid computing environments including CPU/GPU clusters, logging and error tracking facilities, and new more efficient computational modules that exploit graphical processor units (GPUs) when available. The ISCE 3.0 framework is designed to work in an operational environment as well as on a single user’s laptop or compute cluster, with services to discover capabilities and scale computations accordingly.
The retrofitting of advanced avionics to in-service aircraft in order to increase operational safety and flexibility, and reduce operating costs is analyzed. Research in flight management planning and airborne guidance for full-and cost-effective flight is examined. The use of CRTs and thin film electroluminescent displays in aircraft is described. The development of more accurate and reliable fuel gauges using nuclear-based techniques or volumetric measurements to evaluate fluid levels is studied. Advances in airspace systems, such as the Microwave Landing System, and Air Traffic Control Beacon System/Select Mode, the Traffic Advisory and Collision Advance System, and satellite-based communications, navigation, and surveillance are discussed.
Description of the design and testing of a recuperated, closed Brayton-cycle, electrical power conversion system designated the Brayton Cycle Demonstrator (BCD). The system uses electrical heaters as a heat source, argon as the cycle working fluid, and gas-lubricated foil-type bearings. Objectives of the test program include (1) evaluation of the overall system performance characteristics and influences on spacecraft integration, (2) familiarization of personnel with operational methods, and (3) determination of system flexibility by operating at a number of off-design conditions. Results obtained to date are discussed.
Shuttle rendezvous and proximity operations trajectory control techniques are reviewed and it is noted that they have been affected by many factors including Shuttle system design constraints such as limited forward RCS and single point radar failures. Crew training requirements and mission operations constraints such as large launch windows, flexibility, and contingency profile interrupts are also integral factors. The resulting trajectory control design primarily uses ground support for the launch and orbit adjust phases, standardized crew techniques utilizing onboard software for the relative navigation flight phase, and mission unique manual control for a flexible proximity operations phase.
Acceleration control of robotic devices can provide improvements to many space-based operations using flexible manipulators and to ground-based operations requiring better precision and efficiency than current industrial robots can provide. This paper reports on a preliminary study of acceleration measurement on robotic motion during parabolic flights on the NASA KC-135 and a parallel study of accelerations with and without gravity arising from computer simulated motions using TREETOPS software.
The Mission Operations and Data Systems Directorate (MO&DSD) has embarked on a new approach for developing and operating Ground Data Systems (GDS) for flight mission support. This approach is driven by the goals of minimizing cost and maximizing customer satisfaction. Achievement of these goals is realized through the use of a standard set of capabilities which can be modified to meet specific user needs. This approach, which is called the Renaissance architecture, stresses the engineering of integrated systems, based upon workstation/local area network (LAN)/fileserver technology and reusable hardware and software components called 'building blocks.' These building blocks are integrated with mission specific capabilities to build the GDS for each individual mission. The building block approach is key to the reduction of development costs and schedules. Also, the Renaissance approach allows the integration of GDS functions that were previously provided via separate multi-mission facilities. With the Renaissance architecture, the GDS can be developed by the MO&DSD or all, or part, of the GDS can be operated by the user at their facility. Flexibility in operation configuration allows both selection of a cost-effective operations approach and the capability for customizing operations to user needs. Thus the focus of the MO&DSD is shifted from operating systems that we have built to building systems and, optionally, operations as separate services. Renaissance is actually a continuous process. Both the building blocks and the system architecture will evolve as user needs and technology change. Providing GDS on a per user basis enables this continuous refinement of the development process and product and allows the MO&DSD to remain a customer-focused organization. This paper will present the activities and results of the MO&DSD initial efforts toward the establishment of the Renaissance approach for the development of GDS, with a particular focus on both the technical and process implications posed by Renaissance to the MO&DSD.
Recent NASA concepts for human missions to Mars, including the Evolvable Mars Campaign and Design Reference Architecture 5.0, have focused on the conduct of missions with long duration stays on the Martian surface. The decision to focus on long duration missions (typically to a single site) is driven by a desire to increase the perceived sustainability of the human Mars campaign, predicated on the assumption that sustainability is best achieved by maximizing the level of activity on the surface, providing for continuous growth in operations, and promoting pioneering of Mars. However, executing a series of long duration missions to a single site is not the only option for human exploration of Mars that has been proposed. Other architectures have been evaluated that focus on missions with short duration surface stays, with each mission visiting a separate site on the surface. This type of architecture is less efficient in that elements are not typically reused from one mission to the next but requires a far less complex surface architecture. There are potentially valid arguments to be made that a short duration, multiple site approach could result in different types of advantages when compared to the long duration, single site approach to Mars exploration, particularly for initial human missions to Mars. These arguments revolve around four areas: Achieved Value, Risk Mitigation, Developmental Affordability, and Operational Affordability & Flexibility. The question of Achieved Value relates to the prioritization of goals for Martian exploration. As discussed, goals related to pioneering and expanding human presence are often referenced as justifications for the long duration approach. However, there are other competing goals, including science and exploration. While there is not a clear consensus among planetary scientists, many have argued that the value of being able to visit multiple sites could outweigh the value of continually visiting a single site. Risk Mitigation is a major concern for initial human missions to Mars. There are a number of hazards related to operating on the Martian surface that are not well characterized. It may be desirable to conduct a series of short duration missions to better understand the nature of these risks prior to committing to a long duration mission. Developmental Affordability relates to the ability of NASA and its partners to develop and deploy the proposed architecture. Any human missions to Mars will be among the most complex endeavors ever undertaken. The capabilities that must be developed to enable any human Mars missions are extremely challenging. The total design, development, test, and evaluation (DDT&E) budget required to develop just the essential capabilities alone will be substantial. If additional surface capabilities are required to support long duration surface stays, the development effort could be unaffordable. Operational Affordability & Flexibility relates to the continued costs to execute the Mars campaign. Long duration missions, even with some amount of in-situ resource utilization, require a significant level of resupply for every mission. This requires additional launches and in-space transportation assets, increasing the operational complexity and total operational cost. This paper will explore each of the four potential advantages of short duration missions in detail. The authors will present comparisons between proposed long duration and short duration architectures through an evaluation of relevant performance, cost, and risk metrics.
This paper presents a concept for an Operational Land Observing System (OLOS) formulated to satisfy a broad spectrum of perceived user needs for a diverse discipline community. The concept formulated will allow continuous orthographic imaging across multiple spectral bands, near-global stereoscopic imaging, and next-day oblique imaging of any desired spot on earth. Imaging parameters will be adaptable to known phenomena characteristics to facilitate information extraction including optional onboard theme selection. The conceptual system will provide 6- to 12-hour quick-look capability, 48-hour turnaround on all standard imaging products, and a guaranteed data flow schedule reliability for 10 to 20 years. A fleet of successive operational satellites will be used.
The Space Station Freedom Manned Base (SSFMB) will support the operation of the many payloads that may be located within the pressurized modules or on external attachment points. The transaction management (TM) approach presented provides a set of overlapping features that will assure the effective and safe operation of the SSFMB and provide a schedule that makes potentially hazardous operations safe, allocates resources within the capability of the resource providers, and maintains an environment conducive to the operations planned. This approach provides for targets of opportunity and schedule adjustments that give the operators the flexibility to conduct a vast majority of their operations with no conscious involvement with the TM function.
The over-all component performance characteristics of a J71 experimental three-stage turbine with 97 percent design stator areas were determined over a range of speed and pressure ratio at inlet-air conditions of approximately 35 inches of mercury absolute and 700 degrees R. The turbine break internal efficiency at design operating conditions was 0.877; the maximum efficiency of 0.886 occurred at a pressure ratio of 4.0 at 120 percent of design equivalent rotor speed. In general, the turbine yielded a wide range of efficient operation, permitting flexibility in the choice of different modes of engine operation. Limiting blade loading of the third rotor was approached but not obtained over the range of conditions investigated herein. At the design operating point, the turbine equivalent weight flow was approximately 105 percent of design. Choking of the third-rotor blades occurred at design speed and an over-all pressure ratio of 4.2.
This report presents the results of a comparison analysis of candidate Strategic Conflict Management (SCM) strategies as applied to Urban Air Mobility (UAM) operations. The SCM strategies investigated included: no SCM, resource scheduling (RS), resource flow rates (FR), area-based flow rates (AR), and conflict detection and resolution (CR). The study evaluated each strategy against the same 3 levels of flight demand in a representative airspace construct for the Dallas/Fort Worth region. The study also accounted for different levels of uncertainty in operational planning and equivalent levels of trajectory following error. In the analysis, we compared the SCM strategies’ effectiveness in reducing the need for the tactical conflict management layer to act and looked at the metrics of unmitigated losses-of-separation (LOS), flight delays imposed by strategic planning, and throughput of the overall airspace. The study results indicated that the CR strategy was the most effective at reducing LOS and percentage of flights with LOS, even in the presence of trajectory error when uncertainty is accounted for in planning. Thus, if the objective is to reduce the number of actions that the tactical conflict management layer will have to take, in terms of conflicts that may need to be resolved, CR is the strategy to use. The FR strategy was found to be the worst at reducing LOS and percentage of flights with LOS. Thus, it is not very effective at reducing the actions required by a tactical conflict management layer. In the airspace tested, the demand was high enough to produce unacceptable levels of flight delay and reductions of throughput when the SCM strategies were implemented. This was especially evident at the higher levels of trajectory uncertainty and error. The need to account for expected levels of uncertainty becomes more and more important as the demand level increases and as the level of trajectory error increases. This is because the likelihood of flights with LOS increases as the density of operations increases and as the level of trajectory error increases. Accounting for uncertainty in the SCM strategies improves the strategy effectiveness with respect to LOS but increases delays and reduces throughput. Thus, there is a tradeoff between scalability and allowable levels of uncertainty. That is, we can implement an air traffic management construct that allows high levels of uncertainty, but we can expect that same system to have limits on scalability that may be evident even at small demand levels, such as those used in this study. Therefore, the results in this study indicate that an air traffic system should attempt to implement mechanisms appropriate for reducing uncertainty where possible in order to increase the chances for scalability. And this increased level of predictability of operations needs to be balanced with mechanisms for ensuring flexibility when operational conditions and plans need to change, even though those types of changes should be the exception rather than the rule under normal conditions. The study also introduced a trade space that could serve as a mechanism for selecting the appropriate SCM strategy in a trade-off between uncertainty and error, mean flight delay, and the LOS metrics (which this study equates to the potential for tactical conflict management actions). The optimal solution for a given airspace, demand level, and other factors, could likely be a combination of SCM strategies, although this study only compared the use of a single SCM strategy at a time. The CR strategy appeared to have the best opportunity for scalability by limiting the number of potential tactical actions to nearly zero.
The concepts behind operations engineering as applied to the requirements, design, development and testing of data processing systems are presented, together with the associated benefits. The objective of operations engineering is to reduce the overall life cycle costs by integrating operations experience with the development process. To achieve this goal, operations engineering seeks to reduce the development costs by that assuring operational requirements are incorporated into the design and development process as early as possible, and reduce the operational costs by decreasing operations staffing requirements and other related costs through improved system capabilities. The areas for improved system capabilities include: system recovery; data recovery; fault isolation; system operability; system flexibility; system automation; and system reporting. It is described how operations engineering is integrated with the development process, and the difficulties and misconceptions experienced in using operations engineering are discussed.
Several recent research efforts are reviewed here which have applied fuzzy logic in control of flexible-link manipulators. A flexible robot is a distributed parameter system represented by complex nonlinear dynamics, its actuator and the control parameters are non-colocated, and lastly, unstructured/unknown parameters play a significant role in model dynamics of a flexible robot operating in the real world. As a result, control of flexible robots is considered a promising area for application of intelligent control methodologies such as fuzzy logic, genetic algorithms, and neural networks.
This paper uses spatial operators to develop new spatially recursive dynamics algorithms for flexible multibody systems. The operator description of the dynamics is identical to that for rigid multibody systems. Assumed-mode models are used for the deformation of each individual body. The algorithms are based on two spatial operator factorizations of the system mass matrix. The first (Newton-Euler) factorization of the mass matrix leads to recursive algorithms for the inverse dynamics, mass matrix evaluation, and composite-body forward dynamics for the systems. The second (innovations) factorization of the mass matrix, leads to an operator expression for the mass matrix inverse and to a recursive articulated-body forward dynamics algorithm. The primary focus is on serial chains, but extensions to general topologies are also described. A comparison of computational costs shows that the articulated-body, forward dynamics algorithm is much more efficient than the composite-body algorithm for most flexible multibody systems.
Technology requirements for an integrated space transportation system capability which will allow the nation to use space efficiently, reliably, and routinely in the years between 1985 and 2000 with a significant return on invested resources will build on the currently defined space transportation system using shuttle, the IUS, and the advanced upper stage such as the solar electric propulsion system. Contributing technologies should include those which support (1) total reusability with minimal refurbishment; (2) responsiveness to high launch rate requirements when operation and energy are the predominant recurring costs; and (3) maximum flexibility in operation between earth and LEO and between LEO and GEO. Initiatives undertaken to advance the heavy lift to launch vehicles, single stage to orbit vehicles, and orbit transfer vehicles are listed.