Human Factor Evaluation of LED General Luminaire Assemblies for Spacecraft Lighting

Light emitting diodes (LED) are semiconductors that convert electrical energy into light and are used by commercial markets to replace traditional fluorescent and incandescent lighting technologies. Advantages of transitioning to LED technologies in spacecraft are reduced mass, reduced occupied volume, reduced power, improved color control, longer operating life, and lower cost associated with power consumption and disposal. This research provides evidence that selected commercial LEDs used in a solid-state design are capable of meeting NASA and DOD environmental test requirements supported by additional analysis for human factors in search of adverse effects, such as fatigue, eyestrain, and headaches in astronauts. Reliability and human factors are both essential for long term missions where crew habitation relies solely on artificial light sources. In an effort to advance the technology readiness level (TRL) for human spacecraft lighting, a randomized block experimental design for evaluating human factor effects using soft white light, emitted from two different prototype LED designs and a Sylvania fluorescent general luminaire assembly (GLA) representing heritage lighting designed for the International Space Station (ISS). There was no statistical evidence to support claims that the LED technology involved in this research failed for reliability, caused fatigue, eyestrain and/or headache in humans. Based on these research findings, a down-selection was made for full implementation of a solid-state LED design that once flight released by Sierra Space, underwent a human factor confirmation trial in support of earlier results.