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The phase retrieval algorithm developed for the James Webb Space Telescope (JWST) is applied to archival image data that was originally used to characterize the Hubble Space Telescope (HST) primary mirror edge defect. The value obtained for the spherical aberration is compared with earlier values reported by several teams comprising the Hubble Aberration Recovery Project (HARP). Several lessons learned...
Recognizing speakers from their voices is a challenging area of research with several practical applications. Presently speaker verification (SV) systems achieve a high level of accuracy under ideal conditions such as, when there is ample data to build speaker models and when speaker verification is performed in the presence of little or no interference. In general, these systems assume that the features...
Array antennas offer a wide range of opportunities in the variation of their directivity patterns through amplitude and phase control. Peak sidelobe levels may be reduced via amplitude control or weighting across the array aperture. Several authors have made significant contributions in detailing processes for synthesizing these aperture amplitude distributions for the purpose of sidelobe level control...
This paper is an extension of the current research being conducted at the US Army Aviation and Missile Research, Development and Engineering Center. The initial work for this research was presented at the 2004, 2005 and 2006 IEEE Aerospace Conferences in papers titled "Phased Arrays using Dual-Wafer Fabrication / High Integration Processes" (J.C. Rock, 2004), "Integration of Antenna...
Deep space exploration requires vehicles with appropriate autonomous capabilities. In order to accomplish their missions, spacecraft need to respond to potential hazards while seeking to expand human knowledge of deep space. This paper provides an overview of the role of autonomy for space exploration. First, we explore the range of autonomous behavior that is useful in space exploration. Second,...
In this paper we demonstrate a co-operative path-planning algorithm for multi-vehicle simultaneous localisation and mapping (SLAM) that uses information-based measures to maximize the accuracy of a feature map which is constructed from terrain observation made by each vehicle. The SLAM algorithm is distributed amongst the vehicles where each vehicle shares locally built map information via a central...
For most of the history of space exploration, human and robotic programs have been independent, and have responded to distinct requirements. The NASA Vision for Space Exploration calls for the return of humans to the Moon, and the eventual human exploration of Mars; the complexity of this range of missions will require an unprecedented use of automation and robotics in support of human crews. The...
The James Webb Space Telescope (JWST) developed by the National Aeronautics and Space Administration (NASA), represents a significant undertaking in the study of the early formation of galaxies. Dubbed "NASA's Cosmology Time Machine", JWST is scheduled to launch in 2013. One area Goddard Space Flight Center (GSFC) has responsibility for is the Integrated Science Instrument Module (ISIM)...
Knowledge about the Earth system (i.e., the physical-chemical processes that describe its evolution) is generated from global measurements of geophysical parameters taken at appropriate mission observation scenarios. Any given instrument transforms the incoming signal into an instrument-dependent output, from which the scientific observable of interest, say a chemical constituent, is eventually retrieved...
Since the Columbia accident, the National Aeronautics and Space Administration (NASA) has worked extensively to improve its "Lessons Learned" processes so that NASA can avoid repeating past decision making errors. This paper identifies the most serious pitfalls in lessons learned processes that support decisions that must be made in situations with significant risks. We focus on three steps...
The assumptions at the beginning of a trade space exploration are that the decision makers have a model of some complex engineered system that relates design variables to performance and cost metrics, they know what the inputs and outputs to the model are, and they know they will be forming a preference over some subset of the inputs and outputs. What they do not know is the relationship between the...
This paper discusses the application of evolutionary computing to a dynamic space vehicle telecommunication subsystem resource and performance simulation in a parallel processing environment. Our objective is to demonstrate the feasibility, application and advantage of using evolutionary computation techniques for the early design search and optimization of space systems. With this approach, engineers...
Government laboratories and industrial research organizations often choose to outsource research and development (R&D) services to other entities. They may do this to reduce costs, or to gain access to unique capabilities that would be difficult to assemble and maintain in-house. They may manage the process at arm's length, or may choose to be more actively involved. A virtual laboratory is a...
NASA's POLARIS information system provides rapid access to key program and project management requirements, guidance, and tools needed for planning and implementing NASA flight, technology, and infrastructure projects. Developed under leadership of the office of the Chief Engineer, NASA's POLARIS provides an agency-wide, Web-based information system that greatly enhances the support provided to program...
The need for systems engineering training is steadily increasing, as both the defense and commercial markets take on more complex "systems of systems" work. A variety of universities and commercial training vendors have assembled courses of various lengths, format, and content to meet this need. This presentation looks at the requirements for systems engineering training, and discusses techniques...
We describe progress in developing a software tool to help create, communicate, and refine concept of operations (ConOps) information. Information found in a ConOps document is central to our tool. ConOps documents are written in the end user's language, describing how the proposed system should support the users' tasks. While there are some helpful documents prescribing ConOps format, there is little...
The Boeing Company is developing an open integrated vehicle health management (IVHM) architecture; Smiths aerospace is extending and applying it. The charter of the Boeing phantom works is to provide tools and assets that enable next generation vehicles to be more reliable, efficient, capable, and autonomous. In support of those goals Integrated vehicle health management (IVHM) is receiving increased...
One of the most difficult aspects of evaluating competing software architectures is the lack of a basis of comparison. More often than not, software architecture document formats, modeling techniques, and descriptions are so different from one supplier to the next that a direct comparison is virtually impossible. Furthermore, these architecture descriptions may have varying degrees of completeness,...
Usage monitoring entails determining the actual usage of a component on the aircraft and requires accurate recognition of regimes. In this paper, a data mining approach is adopted for regime recognition. In particular, a regime recognition algorithm developed based on hidden Markov models is presented. The developed algorithm was validated using the flight card data of an Army UH-60L helicopter. The...
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