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Simulation of the Mars Surface Solar Spectra for Optimized Performance of Triple-Junction Solar CellsThe unparalleled success of the Mars Exploration Rovers (MER) powered by GaInP/GaAs/Ge triple-junction solar cells has demonstrated a lifetime for the rovers that exceeded the baseline mission duration by more than a factor of five. This provides confidence in future longer-term solar powered missions on the surface of Mars. However, the solar cells used on the rovers are not optimized for the Mars surface solar spectrum, which is attenuated at shorter wavelengths due to scattering by the dusty atmosphere. The difference between the Mars surface spectrum and the AM0 spectrum increases with solar zenith angle and optical depth. The recent results of a program between JPL and Spectrolab to optimize GaInP/GaAs/Ge solar cells for Mars are presented. Initial characterization focuses on the solar spectrum at 60-degrees zenith angle at an optical depth of 0.5. The 60-degree spectrum is reduced to ~1/6 of the AM0 intensity and is further reduced in the blue portion of the spectrum. JPL has modeled the Mars surface solar spectra, modified an X-25 solar simulator, and completed testing of Mars-optimized solar cells previously developed by Spectrolab with the modified X-25 solar simulator. Spectrolab has focused on the optimization of the higher efficiency Ultra Triple-Junction (UTJ) solar cell for Mars. The attenuated blue portion of the spectrum requires the modification of the top sub-cell in the GaInP/GaAs/Ge solar cell for improved current balancing in the triple-junction cell. Initial characterization confirms the predicted increase in power and current matched operation for the Mars surface 60-degree zenith angle solar spectrum.
Document ID
20090022293
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Edmondson, Kenneth M. (Spectrolab, Inc. Sylmar, CA, United States)
Joslin, David E. (Spectrolab, Inc. Sylmar, CA, United States)
Fetzer, Chris M. (Spectrolab, Inc. Sylmar, CA, United States)
King, RIchard R. (Spectrolab, Inc. Sylmar, CA, United States)
Karam, Nasser H. (Spectrolab, Inc. Sylmar, CA, United States)
Mardesich, Nick (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Stella, Paul M. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Rapp, Donald (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Mueller, Robert (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 24, 2013
Publication Date
February 1, 2007
Publication Information
Publication: Proceedings of the 19th Space Photovoltaic Research and Technology Conference
Subject Category
Space Sciences (General)
Distribution Limits
Public
Copyright
Public Use Permitted.

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IDRelationTitle20090022280Collected WorksProceedings of the 19th Space Photovoltaic Research and Technology Conference
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