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NASA NTRS2017

Remediation Technology Collaboration Development - A Compendium

During its multi-year period of performance, the Remediation Technology Collaboration Development (RTCD) task orders initial goals were to enhance the capability to specifically target reductions in the long-term liabilities associated with NASAs most challenging remediation sites. This was accomplished by identifying existing remediation processes and conditions, researching site-specific technologies (both past and present) while simultaneously looking for parallel situations where these technologies could be applied. In addition, the most promising of these solutions were developed from comprehensive research and bench studies into pilot studies or demonstration projects, which contributed significantly to the success of the RTCD program.

Olsen, W.↗

NASA NTRS1987

Multiple arm coordination using concurrent processing

The use of concurrent processing for robot arm coordination is considered, and a hierarchically structured set of routines for the completion of coordinated tasks is discussed. Concurrent programming controls interacting concurrent processes by providing techniques to handle the problems of mutual exclusion, synchronization, and communication. The process is demonstrated for the example of the producer-consumer problem. Software supporting a concurrent environment to control a robotic system is being developed in which parallel rather than sequential thought processes are used.

Basta, Robert A.↗

NASA NTRS1989

Prototype architecture for a VLSI level zero processing system

The prototype architecture and implementation of a high-speed level zero processing (LZP) system are discussed. Due to the new processing algorithm and VLSI technology, the prototype LZP system features compact size, low cost, high processing throughput, and easy maintainability and increased reliability. Though extensive control functions have been done by hardware, the programmability of processing tasks makes it possible to adapt the system to different data formats and processing requirements. It is noted that the LZP system can handle up to 8 virtual channels and 24 sources with combined data volume of 15 Gbytes per orbit. For greater demands, multiple LZP systems can be configured in parallel, each called a processing channel and assigned a subset of virtual channels. The telemetry data stream will be steered into different processing channels in accordance with their virtual channel IDs. This super system can cope with a virtually unlimited number of virtual channels and sources. In the near future, it is expected that new disk farms with data rate exceeding 150 Mbps will be available from commercial vendors due to the advance in disk drive technology.

Shi, Jianfei↗

NASA NTRS2020

Passive Aeroelastic Tailoring

The Passive Aeroelastic Tailoring (PAT) project was tasked with investigating novel methods to achieve passive aeroelastic tailoring on high aspect ratio wings. The goal of the project was to identify structural designs or topologies that can improve performance and/or reduce structural weight for high-aspect ratio wings. This project considered two unique approaches, which were pursued in parallel: through-thickness topology optimization and composite tow-steering.

Smith, Benjamin↗

NASA NTRS1992

Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 4: Advanced fan section aerodynamic analysis

The purpose of this study is the development of a three-dimensional Euler/Navier-Stokes flow analysis for fan section/engine geometries containing multiple blade rows and multiple spanwise flow splitters. An existing procedure developed by Dr. J. J. Adamczyk and associates and the NASA Lewis Research Center was modified to accept multiple spanwise splitter geometries and simulate engine core conditions. The procedure was also modified to allow coarse parallelization of the solution algorithm. This document is a final report outlining the development and techniques used in the procedure. The numerical solution is based upon a finite volume technique with a four stage Runge-Kutta time marching procedure. Numerical dissipation is used to gain solution stability but is reduced in viscous dominated flow regions. Local time stepping and implicit residual smoothing are used to increase the rate of convergence. Multiple blade row solutions are based upon the average-passage system of equations. The numerical solutions are performed on an H-type grid system, with meshes being generated by the system (TIGG3D) developed earlier under this contract. The grid generation scheme meets the average-passage requirement of maintaining a common axisymmetric mesh for each blade row grid. The analysis was run on several geometry configurations ranging from one to five blade rows and from one to four radial flow splitters. Pure internal flow solutions were obtained as well as solutions with flow about the cowl/nacelle and various engine core flow conditions. The efficiency of the solution procedure was shown to be the same as the original analysis.

Crook, Andrew J.↗

NASA NTRS2012

Optical Signature Analysis of Tumbling Rocket Bodies via Laboratory Measurements

The NASA Orbital Debris Program Office has acquired telescopic lightcurve data on massive intact objects, specifically spent rocket bodies, in order to ascertain tumble rates in support of the Active Debris Removal (ADR) task to help remediate the LEO environment. Rotation rates are needed to plan and develop proximity operations for potential future ADR operations. To better characterize and model optical data acquired from ground-based telescopes, the Optical Measurements Center (OMC) at NASA/JSC emulates illumination conditions in space using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. The OMC employs a 75-watt Xenon arc lamp as a solar simulator, an SBIG CCD camera with standard Johnson/Bessel filters, and a robotic arm to simulate an object's position and rotation. The light source is mounted on a rotary arm, allowing access any phase angle between 0 -- 360 degrees. The OMC does not attempt to replicate the rotation rates, but focuses on how an object is rotating as seen from multiple phase angles. The two targets studied are scaled (1:48), SL-8 Cosmos 3M second stages. The first target is painted in the standard government "gray" scheme and the second target is primary white, as used for commercial missions. This paper summarizes results of the two scaled rocket bodies, each rotated about two primary axes: (a) a spin-stabilized rotation and (b) an end-over-end rotation. The two rotation states are being investigated as a basis for possible spin states of rocket bodies, beginning with simple spin states about the two primary axes. The data will be used to create a database of potential spin states for future works to convolve with more complex spin states. The optical signatures will be presented for specific phase angles for each rocket body and shown in conjunction with acquired optical data from multiple telescope sources.

Cowardin, H.↗

NASA NTRS2022

Balancing Predictive and Reactive Science Planning for Mars 2020 Perseverance

The design of the science planning process for a space science mission needs to find a balance between operational and resource constraints and scientific decision-making. Science planning has previously been characterized as either predictive or reactive. Predictive science planning is needed when constraints drive science activities to be planned far in advance. For example, a combination of long one-way light time plus high-stakes science decisions drove the Cassini-Huygens mission to Saturn to have an extremely predictive planning process. On the other extreme, reactive science planning is needed when constraints drive science activities to be planned based on the results of the previous plan. For example, the Mars Exploration Rover mission interacted with the surface of Mars, and so the planning team needed to know the state of the rover at the end of each planning cycle before starting the next cycle. Operational and resource constraints that require management on intermediate timescales has led to the development of a science planning process between these two extremes. For example, the Mars Science Laboratory is a technically complex rover and has a parallel predictive process that allows the operations team to manage engineering constraints several days in advance while maintaining the reactive tactical planning process similar to that of MER. The Mars 2020 Perseverance rover is a technically complex rover in the MSL style, but has an added layer of science complexity: it is tasked with collecting a returnable cache of scientifically valuable samples of Mars within prime mission. Thus, the science planning process also needs to accommodate high-stakes longer-term science decisions in the style of Cassini. In order to balance the push-pull of these constraints, we have developed a science campaign-focused operational paradigm for Mars 2020 Perseverance that allows for both predictive planning to accommodate technological complexity and high-stakes science decisions as well as reactive planning to accommodate the realities of interacting with the martian surface. This paradigm influenced the design of operational processes and operational tools.

Spanovich, Nicole↗

NASA NTRS1977

Controlled flexibility in technical editing - The levels-of-edit concept at JPL

The levels-of-edit concept, which can be used to specify the amount of editorial effort involved in the preparation of a manuscript for publication, is discussed. Nine types of editing are identified and described. These include coordination edit (preparing estimates, gathering cost data, monitoring production processes), policy edit, integrity edit (making sure that parts of a publication match in a physical or numerical sense), screening edit (ensuring that the quality of camera-ready copy is sufficient for external publication), copy clarification edit, format edit, mechanical style edit, language edit, and substantive edit (reviewing the manuscript for content coherence, emphasis, subordination and parallelism). These functions are grouped into five levels of edit. An edit-level number is assigned to each manuscript, providing a quantitative and qualitative indicator of the editing to be done which is clearly understood by authors, managers, and editors alike. In addition, clear boundaries are drawn between normal and extraordinary editing tasks. Individual organizations will group various edits in different ways to reflect their needs and priorities; the essential element of the system is unambiguous definition and coding of the types and amount of work to be done.

Buehler, M. F.↗

NASA NTRS1999

Real Time Optima Tracking Using Harvesting Models of the Genetic Algorithm

Tracking optima in real time propulsion control, particularly for non-stationary optimization problems is a challenging task. Several approaches have been put forward for such a study including the numerical method called the genetic algorithm. In brief, this approach is built upon Darwinian-style competition between numerical alternatives displayed in the form of binary strings, or by analogy to 'pseudogenes'. Breeding of improved solution is an often cited parallel to natural selection in.evolutionary or soft computing. In this report we present our results of applying a novel model of a genetic algorithm for tracking optima in propulsion engineering and in real time control. We specialize the algorithm to mission profiling and planning optimizations, both to select reduced propulsion needs through trajectory planning and to explore time or fuel conservation strategies.

Baskaran, Subbiah↗

NASA NTRS1999

Launch Vehicle Design Process Description and Training Formulation

A primary NASA priority is to reduce the cost and improve the effectiveness of launching payloads into space. As a consequence, significant improvements are being sought in the effectiveness, cost, and schedule of the launch vehicle design process. In order to provide a basis for understanding and improving the current design process, a model has been developed for this complex, interactive process, as reported in the references. This model requires further expansion in some specific design functions. Also, a training course for less-experienced engineers is needed to provide understanding of the process, to provide guidance for its effective implementation, and to provide a basis for major improvements in launch vehicle design process technology. The objective of this activity is to expand the description of the design process to include all pertinent design functions, and to develop a detailed outline of a training course on the design process for launch vehicles for use in educating engineers whose experience with the process has been minimal. Building on a previously-developed partial design process description, parallel sections have been written for the Avionics Design Function, the Materials Design Function, and the Manufacturing Design Function. Upon inclusion of these results, the total process description will be released as a NASA TP. The design function sections herein include descriptions of the design function responsibilities, interfaces, interactive processes, decisions (gates), and tasks. Associated figures include design function planes, gates, and tasks, along with other pertinent graphics. Also included is an expanded discussion of how the design process is divided, or compartmentalized, into manageable parts to achieve efficient and effective design. A detailed outline for an intensive two-day course on the launch vehicle design process has been developed herein, and is available for further expansion. The course is in an interactive lecture/workshop format to engage the participants in active learning. The course addresses the breadth and depth of the process, requirements, phases, participants, multidisciplinary aspects, tasks, critical elements,as well as providing guidance from previous lessons learned. The participants are led to develop their own understanding of the current process and how it can be improved. Included are course objectives and a session-by-session outline of course content. Also included is an initial identification of visual aid requirements.

Atherton, James↗

NASA NTRS1994

VLSI neuroprocessors

Electronic and optoelectronic hardware implementations of highly parallel computing architectures address several ill-defined and/or computation-intensive problems not easily solved by conventional computing techniques. The concurrent processing architectures developed are derived from a variety of advanced computing paradigms including neural network models, fuzzy logic, and cellular automata. Hardware implementation technologies range from state-of-the-art digital/analog custom-VLSI to advanced optoelectronic devices such as computer-generated holograms and e-beam fabricated Dammann gratings. JPL's concurrent processing devices group has developed a broad technology base in hardware implementable parallel algorithms, low-power and high-speed VLSI designs and building block VLSI chips, leading to application-specific high-performance embeddable processors. Application areas include high throughput map-data classification using feedforward neural networks, terrain based tactical movement planner using cellular automata, resource optimization (weapon-target assignment) using a multidimensional feedback network with lateral inhibition, and classification of rocks using an inner-product scheme on thematic mapper data. In addition to addressing specific functional needs of DOD and NASA, the JPL-developed concurrent processing device technology is also being customized for a variety of commercial applications (in collaboration with industrial partners), and is being transferred to U.S. industries. This viewgraph p resentation focuses on two application-specific processors which solve the computation intensive tasks of resource allocation (weapon-target assignment) and terrain based tactical movement planning using two extremely different topologies. Resource allocation is implemented as an asynchronous analog competitive assignment architecture inspired by the Hopfield network. Hardware realization leads to a two to four order of magnitude speed-up over conventional techniques and enables multiple assignments, (many to many), not achievable with standard statistical approaches. Tactical movement planning (finding the best path from A to B) is accomplished with a digital two-dimensional concurrent processor array. By exploiting the natural parallel decomposition of the problem in silicon, a four order of magnitude speed-up over optimized software approaches has been demonstrated.

Kemeny, Sabrina E.↗

NASA NTRS2001

Bit-serial neuroprocessor architecture

A neuroprocessor architecture employs a combination of bit-serial and serial-parallel techniques for implementing the neurons of the neuroprocessor. The neuroprocessor architecture includes a neural module containing a pool of neurons, a global controller, a sigmoid activation ROM look-up-table, a plurality of neuron state registers, and a synaptic weight RAM. The neuroprocessor reduces the number of neurons required to perform the task by time multiplexing groups of neurons from a fixed pool of neurons to achieve the successive hidden layers of a recurrent network topology.

Tawel, Raoul↗

NASA NTRS2009

Going South: Lessons from an Historic Project Failure

NASA's successful conduct of the Apollo Program greatly enhanced the prestige of the United States and remains broadly accepted as America's gift to all Mankind. NASA's accomplishments continue to amaze the world. With the Vision for Space Exploration (VSE) Americans once again tasked NASA to carry out a project that is expected to provide inspiration and economic stimulus to the United States and to the world. In preparation NASA has thoroughly examined space program precedents. There is, however, another precedent which has not been examined in this context but whose scope and environment in many ways parallel the VSE. This project was initiated by a team that had, ten years before, successfully completed an effort that, at a cost of $151 billion (2008 values), had pushed the envelope of technology, brought economic growth, established their country as the world leader in engineering, and been broadly accepted as their country s gift to Mankind. The new project was again inspired by popular desire to enhance national prestige and make yet another major contribution to Humanity. The new effort was predicted to require eight years and $156 billion (2008 values). However, after eight years and expenditures of 80% beyond the baseline, the project collapsed amid bankruptcy, political scandal, and criminal prosecution. This paper applies current aerospace project metrics, such as earned value analysis, to review the strategic decisions in this historic failure and describe its ultimate collapse. Key mistakes are identified, and lessons are drawn which may prove useful in guiding the VSE.

Scott, John H.↗

NASA NTRS2009

Going South: Analysis of an Historic Project Engineering Failure

NASA's successful conduct of the Apollo Program greatly enhanced the prestige of the United States and remains broadly accepted as America's gift to all Mankind. NASA's accomplishments continue to amaze the world. With the Vision for Space Exploration (VSE) Americans once again tasked NASA to carry out a project that is expected to provide inspiration and economic stimulus to the United States and to the world. In preparation NASA has thoroughly examined space program precedents. There is, however, another precedent which has not been examined in this context but whose scope and environment in many ways parallel the VSE. This project was initiated by a team that had, ten years before, successfully completed an effort that, at a cost of $173 billion (in 2008 dollars), had pushed the envelope of technology, brought economic growth, established their country as the world leader in engineering, and been broadly accepted as that country's gift to all Mankind. The new project was again inspired by popular desire to enhance national prestige and make yet another major contribution to Humanity. This effort was predicted to require eight years and $156 billion (2008 dollars). However, after nine years and expenditures of 96% beyond the baseline, the project collapsed amid bankruptcy, political scandal, and criminal prosecution. This paper applies current project management metrics, such as earned value analysis, to review the strategic decisions in this historic failure and describe its ultimate collapse. Key mistakes are identified, and lessons are drawn which may prove useful in guiding the VSE.

Scott, John H.↗

NASA NTRS1996

Parallelization of Rocket Engine System Software (Press)

The main goal is to assess parallelization requirements for the Rocket Engine Numeric Simulator (RENS) project which, aside from gathering information on liquid-propelled rocket engines and setting forth requirements, involve a large FORTRAN based package at NASA Lewis Research Center and TDK software developed by SUBR/UWF. The ultimate aim is to develop, test, integrate, and suitably deploy a family of software packages on various aspects and facets of rocket engines using liquid-propellants. At present, all project efforts by the funding agency, NASA Lewis Research Center, and the HBCU participants are disseminated over the internet using world wide web home pages. Considering obviously expensive methods of actual field trails, the benefits of software simulators are potentially enormous. When realized, these benefits will be analogous to those provided by numerous CAD/CAM packages and flight-training simulators. According to the overall task assignments, Hampton University's role is to collect all available software, place them in a common format, assess and evaluate, define interfaces, and provide integration. Most importantly, the HU's mission is to see to it that the real-time performance is assured. This involves source code translations, porting, and distribution. The porting will be done in two phases: First, place all software on Cray XMP platform using FORTRAN. After testing and evaluation on the Cray X-MP, the code will be translated to C + + and ported to the parallel nCUBE platform. At present, we are evaluating another option of distributed processing over local area networks using Sun NFS, Ethernet, TCP/IP. Considering the heterogeneous nature of the present software (e.g., first started as an expert system using LISP machines) which now involve FORTRAN code, the effort is expected to be quite challenging.

Cezzar, Ruknet↗

NASA NTRS1988

Space spider crane

A space spider crane for the movement, placement, and or assembly of various components on or in the vicinity of a space structure is described. As permanent space structures are utilized by the space program, a means will be required to transport cargo and perform various repair tasks. A space spider crane comprising a small central body with attached manipulators and legs fulfills this requirement. The manipulators may be equipped with constant pressure gripping end effectors or tools to accomplish various repair tasks. The legs are also equipped with constant pressure gripping end effectors to grip the space structure. Control of the space spider crane may be achieved either by computer software or a remotely situated human operator, who maintains visual contact via television cameras mounted on the space spider crane. One possible walking program consists of a parallel motion walking program whereby the small central body alternatively leans forward and backward relative to end effectors.

Macconochie, Ian O.↗

NASA NTRS1992

Network issues for large mass storage requirements

File Servers and Supercomputing environments need high performance networks to balance the I/O requirements seen in today's demanding computing scenarios. UltraNet is one solution which permits both high aggregate transfer rates and high task-to-task transfer rates as demonstrated in actual tests. UltraNet provides this capability as both a Server-to-Server and Server-to-Client access network giving the supercomputing center the following advantages highest performance Transport Level connections (to 40 MBytes/sec effective rates); matches the throughput of the emerging high performance disk technologies, such as RAID, parallel head transfer devices and software striping; supports standard network and file system applications using SOCKET's based application program interface such as FTP, rcp, rdump, etc.; supports access to the Network File System (NFS) and LARGE aggregate bandwidth for large NFS usage; provides access to a distributed, hierarchical data server capability using DISCOS UniTree product; supports file server solutions available from multiple vendors, including Cray, Convex, Alliant, FPS, IBM, and others.

Perdue, James↗

NASA NTRS1992

Developing a control system for ARES 2

A great deal of analysis and testing is conducted at the NASA Langley Research Center to support the development of safe and reliable helicopter rotor systems. This work is performed by the Rotorcraft Aeroelasticity Group located in the Transonic Dynamics Tunnel (TDT) facility. Over the past two decades a wide variety of tests have been successfully conducted in the TDT and their results have contributed significantly to the understanding of aeromechanical phenomena in rotor systems. This has led to improved tools for analysis and design, and ultimately to the development, of improved rotor systems. The TDT facility is ideally suited for these tests due to its unique ability to use a heavy gas as a working medium. This allows the model to be scaled such that the results obtained may be readily extrapolated to full scale. Until recently, the rotor system to be tested has been mounted on a fixed balance which is attached to the longeron which is attached to the stand through a single pitching degree of freedom. The testbed used is known as the Aeroelastic Rotor Experimental System (ARES 1). In order to extend the experimental capabilities to investigate the full rotor/body dynamic coupling present in a rotorcraft, a very ambitious project has been undertaken to design and construct a six degree of freedom system that can be controlled so as to emulate the inertial characteristics of a prescribed model fuselage. The electronic and mechanical hardware for this system has already been designed and constructed. This system is known ar ARES II. The rotor and its drive system are mounted on the balance which is attached to the longeron via six hydraulic actuators. This six degree of freedom parallel linkage is referred to in the literature as a Stuart Platform. By properly adjusting the length of the hydraulic actuators it is possible to position and orient the balance relative to the longeron. The longeron is attached to the stand via a pitch degree of freedom to allow testing over various forward flight regimes. One major task remaining to complete this testbed is the design and synthesis of a control system. To do this properly requires an understanding of the kinematics and dynamics of the system and robust control design. A brief description of the development of a control design is given.

Fitzsimons, Philip M.↗