(Photo: AP/NASA TV)
Before we get into the "how many astronauts does it take to screw in a light bulb" jokes, let's ask first why NASA is embarking on a mission to replace all the lights on the International Space Station.
Turns out they're burned out -- not the light bulbs necessarily (well, some of them are) but the astronauts. According to an article in Scientific American, regardless of all the pills they might pop, relaxation methods they employ and "sleep hygiene" classes they take, astronauts on the ISS are only getting an average of six hours of sleep each night.
NASA medical officer and flight surgeon Smith Johnston said these hours of missed sleep "adds up." The astronauts are allotted up to 8.5 hours of sleep each night. Although the lights might not be the only problem -- Scientific American notes floating in bed and constant noise among other factors -- NASA is investing $11.4 million to change out the fluorescent bulbs to fix the problem.
In this image provided by NASA, astronauts Pam Melroy, George Zamka, bottom right,and European Space Agency's Paolo Nespoli, sleep in their sleeping bags, which are secured on the middeck of the Space Shuttle Discovery while docked with the International Space Station, Thursday, Nov. 1, 2007. (Photo: AP/NASA)
The new bulbs they'll replace them with, scientists hope, will allow the astronauts to operate on a normal circadian rhythm. Those developing the new light bulbs will capitalize on knowledge there is a specialized cell in the eye when exposed to blue light wavelengths will suppress melatonin production by the brain and therefore help one avoid sleepiness, whereas red wavelengths will do the opposite. The challenge comes with making the new light have the same "footprint of their predecessors," as Katie Worth for Scientific American put it. According to Boeing project contractor Debbie Sharp, this means it would need to have more than 100 LED bulbs in a rainbow of color cloaked by a diffuser that makes them look like a panel of white light.
Here's more on how they're expected to work:
The fixtures have three modes, each with a subtly different hue: White light is for general vision; a cooler blue-shifted light promotes alertness (useful in the morning, during mid-sleep emergencies or amidst the schedule shifts that regularly slam their 24-hour rhythms from Houston time to Moscow time); and a warmer red-shifted light triggers sleepiness (helpful at bedtime). And LEDs have the additional bonus of being lighter, cooler, more durable, less toxic and more energy-efficient than fluorescents.
Boeing and its subcontractors, who are still tinkering with the final design, expect to deliver 20 lamps in 2015—right when the station will be down to its last spare bulbs. In the meantime the National Space Biomedical Research Institute has funded the labs of neuroscientists George Brainard at Thomas Jefferson University and Steven Lockley at Harvard University to test the lamps' efficacy. Brainard is studying whether the lights indeed help people in simulated ISS sleeping quarters doze off faster. Lockley is investigating whether the lights—in combination with caffeine—help volunteers perform complex tasks during night shifts.
Elizabeth Klerman with Harvard Medical School's Division of Sleep Medicine told Scientific American she foresees similar technology being used in Earthly light bulbs in the future.
(H/T: Popular Science)