Wide Awake in Outer Space

But even with this information, scientists still need to answer some basic questions in order to develop countermeasures against unwanted wakefulness. For instance, what exactly controls the master clock? What intensity of light will trigger it - and which colours? Does gravity itself provide a cue? All these questions will grow in importance as humans move farther into space.

Take the exploration of Mars, for example. On Mars, daylight is primarily yellowish-brown. On Earth, it's blue-green. How will the human clock respond to the unearthly colour of Martian skies? Some research indicates that it could make a difference. Melatonin production, for example, is suppressed more by some wavelengths of light than by others.

Of more concern, perhaps, is the length of the Martian day: 24 hours and thirty-nine minutes. "That is significantly different than the period of the clock in humans,” notes Wright. It's possible, he says, that the human clock might not be able to adapt to Mars. Ongoing research addresses this question by exploring countermeasures - for example, different patterns of light exposure - that will entrain the human clock to a longer day.

Learning to manage the circadian clock is critical to exploring space. But astronauts are hardly the only ones with sleep problems.

"The space environment," says Wright, "provides us with a unique opportunity to understand something more about the functions of sleep." Part of the research involves trying to understand ways to promote wakefulness for shift workers, or people suffering jet lag, or simply for the many people who don't get enough sleep.

"It's an exciting topic,” says Wright, "because it affects everyone.” Indeed, countermeasures that Wright and his colleagues devise for astronauts in space might well provide a more restful night for those of us remaining on Earth.