Changes in light exposure can affect sleep, digestion, cognitive performance, and mood — a phenomenon known to people who experience jet lag, night-shift work, or the seasonal blahs associated with the shorter days of winter.
Initially, NASA planned to replace the lights on the space station with LED fixtures purely because they last much longer than fluorescents and are energy efficient. But when Brainard heard about the plan, he and a handful of other experts urged the agency to modify the specifications so that the lights could be a tool for maintaining astronaut health…
The lights will have three “on” settings — one to boost alertness in the morning, one to help astronauts relax before bed, and a regular mode for midday. All of them appear white, more or less, but the morning setting is brighter and is “enriched” with cool, bluish tones, while the evening setting is heavier on warmer, reddish hues.
I could turn this into a long rant about fluorescent lighting, especially the “green” bulbs that the government is mandating, but I won’t. Suffice to say, the part of the article I like best is that the astronauts will have a choice for how much light they want. If the bluer, brighter light gives ’em a headache, switch to the lower setting. I think the LEDs would be less hazardous than the old fluorescents. Using less power is a good idea, too, especially as more science experiments come online and the solar arrays slowly degrade over time.