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Power and Propulsion System Design for Near-Earth Object Robotic ExplorationNear-Earth Objects (NEOs) are exciting targets for exploration; they are relatively easy to reach but relatively little is known about them. With solar electric propulsion, a vast number of interesting NEOs can be reached within a few years and with extensive flexibility in launch date. An additional advantage of electric propulsion for these missions is that a spacecraft can be small, enabling a fleet of explorers launched on a single vehicle or as secondary payloads. Commercial, flight-proven Hall thruster systems have great appeal based on their performance and low cost risk, but one issue with these systems is that the power processing units (PPUs) are designed for regulated spacecraft power architectures which are not attractive for small NEO missions. In this study we consider the integrated design of power and propulsion systems that utilize the capabilities of existing PPUs in an unregulated power architecture. Models for solar array and engine performance are combined with low-thrust trajectory analyses to bound spacecraft design parameters for a large class of NEO missions, then detailed array performance models are used to examine the array output voltage and current over a bounded mission set. Operational relationships between the power and electric propulsion systems are discussed, and it is shown that both the SPT-100 and BPT-4000 PPUs can perform missions over a solar range of 0.7 AU to 1.5 AU - encompassing NEOs, Venus, and Mars - within their operable input voltage ranges. A number of design trades to control the array voltage are available, including cell string layout, array offpointing during mission operations, and power draw by the Hall thruster system.
Document ID
20150006904
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
External Source(s)
Authors
Snyder, John Steven
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Randolph, Thomas M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Landau, Damon F.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Bury, Kristen M.
(NASA Glenn Research Center Cleveland, OH, United States)
Malone, Shane P.
(NASA Glenn Research Center Cleveland, OH, United States)
Hickman, Tyler A.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
April 29, 2015
Publication Date
July 31, 2011
Subject Category
Spacecraft Propulsion And Power
Meeting Information
Meeting: AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
Location: San Diego, CA
Country: United States
Start Date: July 31, 2011
End Date: August 3, 2011
Sponsors: American Inst. of Aeronautics and Astronautics, American Society for Engineering Education, American Society of Mechanical Engineers, Society of Automotive Engineers, Inc.
Distribution Limits
Public
Copyright
Other
Keywords
Near Earth Object (NEO)
unmanned spacecraft
Planetary Science Decadal Survey

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