By Liat Clark, Wired UK

A neuroscientist is working with NASA to develop special lamps that could help restore the circadian rhythm of exhausted astronauts working aboard the International Space Station (ISS).

[partner id="wireduk"]Thomas Jefferson University neuroscientist George C Brainard, who has headed up the university's Light Research Program since 1984, received approval for the lights in early 2012 and 100 of the LED models are due to be sent to NASA by mid-2015. The lights have three different color temperatures to help ease the astronauts into morning, nighttime and normal working mode.

"An astronaut here on Earth experiences a 24-hour day/night cycle just like you and I," explained Brainard in a 2008 interview with EarthSky.org. "Now when they're on the space station, they're circling the planet every 90 minutes. So they've gone from a 24-hour day to a 90-minute day."

As well as having to deal with the bright light of the sun reflected off the Earth, astronauts at ISS also have to be prepared to work all hours of the day if emergencies crop up or docking maneuvers have to be completed in the middle of a sleep cycle. NASA flight surgeon Smith Johnston says astronauts get around six hours sleep, on average, compared to the eight and a half they are allotted.

"Every one of us has probably done an all-nighter or two in our lives," Brainard said in the interview. "You feel crummy the next day, but you bounce back. And you also get your recovery sleep. [Astronauts] are not getting their recovery sleep. That's the problem. Day in, day out, they're missing the ingredients for best health and best behavioral regulation."

Brainard was one of several experts in the field that approached NASA after receiving word that the Station's old and unforgiving fluorescent lights would be replaced by LED bulbs. Whatever is used to replace the lamps would have to be tailored to an exacting 17.8cm by 66cm fit, so it's not a job that is done often and, since lighting has been shown to affect sleep, cognitive performance and mood, tailoring the lamps further could mean a more productive, happy workforce aboard the ISS.

From his studies, Brainard already knew that a certain blue light could be used to suppress melatonin levels in the body – the hormone responsible for regulating the sleep cycle. He decided to test out the affect of different light tones, including this blue tone, on astronauts in a rather novel way, building confined sleeping quarters that replicate those on the space station and asking volunteers to spend hours in the closet-sized spaces. He measured the levels of melatonin present in the candidates after they were exposed to different lamps and found that pure blue light suppresses melatonin-production more than white light, so would be useful in waking the astronauts. He is now testing how it affects alertness in relation to this.

"If an astronaut is wakened up out of sleep and there has to be a spacewalk for emergency purposes, you want that astronaut at their peak alertness," explained Brainard in the interview.

A pretty significant flaw in the work initially was that astronauts cannot work in an environment with colored lights, as they need to distinguish colors when working on the space station – cutting the white wire instead of the blue could prove disastrous when repairing the electrics. The compromise is that the all the lights fall under the white spectrum, with different subtle tones – when the astronauts wake, the light will turn brighter with cool blue tones and in the evening, warmer with heavier red tones.

The lamps need to undergo further testing to ensure they are robust enough to withstand space travel, but otherwise the team at NASA and the collaborators at the National Space Biomedical Research Institute and Boeing are ready to move forward with the plan.

Source: Wired.co.uk