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Off-Nominal Performance of the International Space Station Solar Array Wings Under Orbital Eclipse Lighting ScenariosThis paper documents testing and analyses to quantify International Space Station (ISS) Solar Array Wing (SAW) string electrical performance under highly off-nominal, low-temperature-low-intensity (LILT) operating conditions with nonsolar light sources. This work is relevant for assessing feasibility and risks associated with a Sequential Shunt Unit (SSU) remove and replace (R&R) Extravehicular Activity (EVA). During eclipse, SAW strings can be energized by moonlight, EVA suit helmet lights or video camera lights. To quantify SAW performance under these off-nominal conditions, solar cell performance testing was performed using full moon, solar simulator and Video Camera Luminaire (VCL) light sources. Test conditions included 25 to 110 C temperatures and 1- to 0.0001-Sun illumination intensities. Electrical performance data and calculated eclipse lighting intensities were combined to predict SAW current-voltage output for comparison with electrical hazard thresholds. Worst case predictions show there is no connector pin molten metal hazard but crew shock hazard limits are exceeded due to VCL illumination. Assessment uncertainties and limitations are discussed along with operational solutions to mitigate SAW electrical hazards from VCL illumination. Results from a preliminary assessment of SAW arcing are also discussed. The authors recommend further analyses once SSU, R&R, and EVA procedures are better defined.
Document ID
Document Type
Preprint (Draft being sent to journal)
Kerslake, Thomas W.
(NASA Glenn Research Center Cleveland, OH, United States)
Scheiman, David A.
(Ohio Aerospace Inst. Brook Park, OH, United States)
Date Acquired
September 7, 2013
Publication Date
October 1, 2005
Subject Category
Spacecraft Design, Testing And Performance
Report/Patent Number
AIAA Paper 2005-5671
Meeting Information
Third International Energy Conversion Engineering Conference American Institute of Aeronautics and Astronautics, Inc.(San Francisco, CA.)
Funding Number(s)
WBS: WBS 22-336-31-01-AB
Distribution Limits
Work of the US Gov. Public Use Permitted.

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