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Hybrid solar and electric lighting (HYSEL) systems constitute the latest generation of lighting systems for advanced life support, exhibiting continued potential for reducing the significant electrical power demand of current bioregenerative life support systems (BLSS). Two experimental HYSEL systems were developed: one employing xenon-metal halide (XMH) lamps and the other adopting light-emitting diodes (LEDs) as the electric-lighting components, and both using a mirror-based, fiberoptic-based solar collection system. The results showed that both the XMH and LED HYSEL systems effected reduced effective plant growing volume, indicating potential for a compact plant hardware design. The apparent electrical conversion efficiency of the LED HYSEL system exceeded that of the XMH HYSEL system by five-fold. Both the XMH and LED HYSEL systems provided reasonably acceptable spectral quality and lighting uniformity.

Significant reductions in electrical-power demand as well as in related mass and physical volume might be achieved if available extraterrestrial solar irradiance could be utilized for plant production in a Bioregenerative Life Support System (BLSS) on Mars. Working estimates of the available photosynthetic photon flux (PPF) at Chryse Planitia (22.3° N, 47.9° W), landing site for the Viking Lander 1 (VL-1) on Mars and geographically near the Mars Pathfinder's landing site, were simulated based on the year-long actual irradiance measurements and downward spectral characteristics made by VL-1 in the 1970's. The results showed that the Wm−2 to µmol m2 s−1 conversion factors for Earth and Mars are essentially equal, being approximately 4.6 µmol m−2 s−1/Wm−2. For half of the total sunshine hours at Chryse Planitia for a whole Martian year, the incident PPF level is at least 400 µmol m−2 s.