Engineering topics
Herzig, Sebastian J. I.
Publications and source records attributed to Herzig, Sebastian J. I..
Kigen: Supporting Spacecraft Design through Applied Artificial Intelligence
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SysML and beyond: applications of MBSE at the NASA Jet Propulsion Laboratory
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Satellite Constellation Orbit Design to Enable a Space-Based Radio Interferometer
Two different design methods for a networked constellation of N small satellites are presented. In the first method, the (linear) Clohessy-Wilthsire equations are used as an initial design tool, followed by conversion to a two-body model. Discrepancies between the linear and nonlinear solutions are minimized in the conversion process. The second method utilizes invariant manifold theory, by perturbing a reference trajectory in different directions along the center eigenvectors. Both methods require 5N parameters to fully define a constellation. In a relative, rotating frame of the reference path, the spacecraft appear as periodic ellipses of varying sizes. Deployment, reconfiguration using propulsive maneuvers, and station keeping costs for an example mission scenario are addressed.
Satellite constellation orbit design to enable a space-based radio interferometer
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Model-based systems engineering at the Jet Propulsion Laboratory: past, present, and future
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Analyzing the Operational Behavior of the Alignment and Phasing System of the Thirty Meter Telescope using SysML
The Alignment and Phasing System (APS) of the Thirty Meter Telescope (TMT) is responsible for positioning individual segments of the primary mirror, as well as the secondary and tertiary mirrors. Given its essential role, understanding the as-speci ed behavior and verifying related requirements is vital to the correct operation of the TMT. Analyzing the behavior of APS is challenging due to the variety of interactions with other subsystems. This paper presents results from developing an integrated system model that captures the structure, behavior, and requirements in a formal modeling language to enable automated veri cation using appropriate solvers. Speci cally, demonstrated and discussed are the results of applying a Systems Modeling Language (SysMLTM) based approach in which operational modes, behavior speci cations and use case scenarios are used for the purpose of verifying requirements on timing, power, and pointing error through system-level simulation using a single, integrated model.
Towards a Reference Architecture for Model-Based Engineering Environments
A key aspect of adopting model-based systems engineering as a practice in an organization is the design and development, and adoption of corresponding processes and tools that support the model-based paradigm. In an effort to enable the unified implementation of such processes and tools, this paper introduces a reference architecture model that serves as a specification for a model-based engineering environment. Current systems engineering practices, products, processes and technologies are used as input for continuously refining the architecture model. In the paper, we introduce and report on the current status of this reference architecture model, and present the methodology applied in developing the reference architecture. We conclude that while there are a very large number of domain- or application-specific processes requiring specialized behavior, these can be reduced through abstraction to a small set of core functions that need to be supported by a realization of a model-based engineering environment. Only very few organization-domain- or application-specific aspects require specialized consideration.