Living on Mars Time: Scientists Suffer Perpetual Jet Lag
Morten Bo Madsen sits next to his blue LED light box as he works. The light box is supposed to help extend Madsen's day by regulating his circadian cycle. Madsen, of the University of Copenghagen, works on the robotic arm camera for the Phoenix Mars Lander mission.
Credit: University of Arizona

Morten Bo Madsen spends his work day crunching data on a laptop seated in front of a clear plastic-covered box about the size of a widescreen computer monitor that emits a startlingly bright blue light.

No, this isn't a scene from a sci-fi movie. Madsen is one of the 150 scientists and engineers working on NASA's Phoenix Mars Lander mission. The bright light keeps Madsen's internal clock in check, because Madsen, you see, is living on Mars time.

Phoenix is a $420 million mission with the aim of sampling and analyzing the dirt and subsurface ice layer in the north polar regions of Mars as it looks for signs that the red planet may have been habitable at some point in the past.

Since the spacecraft landed on Mars on May 25, mission controllers have been living on its schedule, or rather the exact opposite of it. When the spacecraft is sleeping during the Martian night, the scientists are up analyzing data; when the spacecraft rises at the beginning of the day on Mars, they retire and let Phoenix do its work.

This may not sound like too taxing a schedule, but there are a couple of catches: Mars' day is 40 minutes longer than Earth's, and the start of the Martian day is always changing with respect to Earth time, as a result of their respective orbital motions.

Living on a schedule that shifts forward by 40 minutes everyday can wreak havoc on the human body, creating an effect that is essentially like perpetual jet lag.

"It would be like traveling two time zones every three days," said physiologist Laura Barger of Harvard Medical School and Brigham and Women's Hospital in Boston.

Barger and her colleagues are studying Madsen and 18 other Phoenix team members as they try to adapt to their Martian schedule, monitoring them for signs of fatigue as well as providing tips for how to live out-of-sync with the rest of the world. The results could help guide future space travelers and Mars missions.

Studying Mars time

All humans possess an internal "circadian" clock that runs on a roughly 24-hour cycle, modulated by the daily shifts between light and dark as the Earth rotates.

"We know that light is the most important time cue to the circadian clock," because it tells the brain what time of day it is and what the body should be doing, Barger said.

Anyone who has flown between time zones knows that the abrupt shift in the time of day can throw sleeping and eating schedules out of whack. The same came happen to swing and night shift workers.

Living on Mars time can create the same issues, because "you have sort of a rotating shift with the Martian day put on top of it," as Barger describes it.

"We knew from our laboratory work when we simulate people living on a Martian day that they have misaligned circadian rhythms," she said. "They're not able to adjust. They have problems sleeping."

NASA officials and researchers were aware of the difficulties that the teams for 1997's Pathfinder mission and the 2003 Mars Exploration Rover missions had when they tried living on Mars time. Phoenix principal investigator Peter Smith spoke with one of Barger's colleagues about coming to help his scientists adjust to their demanding schedule, and NASA agreed to fund the study.

Live tests

Barger and her team are intensely monitoring and working with the Phoenix team members in Tucson, Ariz.,, who all volunteered for the study. The medical team is providing the Phoenix crew with ways to adjust to their extreme schedule (Madsen's blue light box, for example), as well as tracking the effects that living on Mars time has on them.

Each study participant wears an "actigraph" watch that monitors his or her motion (people move less when they sleep) as well as their exposure to light, that essential circadian cue. They also complete computer game-like reaction time tests before and after each shift. They use a scale on a computer to describe their mood (tired people can often be grumpy) and to test their memory while they're on duty. The Harvard team is also measuring levels of a metabolite of melatonin in samples of participants' urine.

Because melatonin responds directly to the circadian clock, measuring its levels "tells us what time the clock is on, if you will," Barger explained, letting the researchers know whether or not the Phoenix team members were adjusting to their schedule.

The light boxes given to the participants help regulate their circadian clocks, giving them the light cues they miss on their shifting schedule.

"Normally when you're just living here on Earth, you have a 24-hour light-dark cycle, and your clock gets reset every day," Barger explained. "When you are living on a Mars day, your clock would have to be lengthened every day by about a half hour. We know that bright light [particularly at the blue end of the spectrum] in the evening will help lengthen the day, so we've given them this light box."

The Harvard team is also providing Phoenix crew members with simple tips for dealing with fatigue, including drinking small cups of coffee throughout the day, instead of a Venti mocha right before their shift; taking naps if their head starts bobbing at the computer; getting a full night's sleep and staying on Mars time even on days off.

How to live on Mars time

Madsen, a scientist from the University of Copenhagen who works with the lander's robotic arm camera, says Mars time actually hasn't been too hard for him. As one of six Danes temporarily living and working together while they're in Tucson for Phoenix's three-month primary mission, he says the camaraderie has helped him deal with the continually shifting schedule.

"We try to live like a family, and get up together in the morning, have breakfast together. And we keep each other on a tight schedule," he told

Troy Hudson, a NASA Jet Propulsion Laboratory engineer with the lander's Microscopy, Electrochemistry and Conductivity Analyzer, has also had little trouble keeping on Mars time, clearly reveling in the experience.

"Personally, I rather enjoyed living on a Mars schedule, both for its, just, fundamental unusualness, and of course it has made working with the spacecraft easy," he said, though maintaining his pre-work gym routine when he was waking up at 2 a.m. was a challenge.

Hudson, who is applying to be an astronaut, said that sitting in front of one of the brilliant blue LED light boxes took some getting used to, though he grew accustomed to it within a week or two.

Madsen agreed. Even though everyone walks around with a bloodless pallor, he thinks that "it's doing its job producing something that is similar, more or less similar to daylight, which helps us staying awake."

Not everyone has found the experience as easy as Madsen and Hudson.

Night owls vs. early risers

Deborah Bass, a project scientist on the mission, says that the shift work can be harder for early risers like her than for night owls. "I like mornings. So doing this night work for me is extremely difficult," she said, adding: "I also really thrive on routine. So for me, this is also exceptionally challenging."

Madsen did note that sometimes he didn't sleep through the night and would be tired the next day at work. In these cases he would take a brief snooze in nap rooms provided to the scientists. "Just 10-20 minutes, you're just as new again," he said. Hudson has never used the nap rooms, he said, though he acknowledged that "occasionally I have felt that tired."

Bass also lived on Mars time during the MER primary missions and monitored the effects of the schedule on the MER team for NASA, and said that the Phoenix team is experiencing some of the same difficulties.

For people who live in Tucson, where mission operations are based, the stress of living on Mars time can actually be greater because staffers try to interact with their families on their days off. They may try to switch back-and-forth from Mars time, making the adjustment for their body harder. If they stayed on Mars time, they wouldn't be able to interact with their families as much. Crew members coming from other institutions and living temporarily in Tucson don't have the same pressure to interact with their families, Bass said.

Madsen and his Danish colleagues, for example, mostly email with their families, only seeing them on week-long trips back to Denmark ? switching back to Earth time is a little easier for longer periods like this, they said.

Social life suffers

Bass and other mission scientists also said that it was difficult to interact with society on the rotating Mars schedule ? the options for socializing are slim if you're getting off of work at 3 or 4 a.m. Errands and laundry can't be done in the middle of the night either.

"So even on your days off, you may not be really getting absorbed back into your normal life," Bass said. "Life is hard to maintain."

Along those lines, Madsen told a story of an encounter during an early morning hiking trip with his colleagues that shows the disconnect the scientists can feel with the outside world. Some passing hikers on the trail said, "Good morning." Madsen and his companions had to stop and think for a moment before replying "Good morning," because to them, it was almost bed-time.

On the whole, Bass said that the reaction to living on Mars time is "very individually driven." Some, like Hudson, thrived on the schedule; others, like Bass, have struggled with it (Bass says the experience has given her more appreciation for the schedule her husband works as an ER doctor).

Overall though, Bass thinks the team is doing well and credits their drive and passion for the mission, a once-in-a-career opportunity for many of them, for much of this.

"The team is extremely dedicated; the team has no intention of letting up, and they absolutely, again, they feel extremely privileged to have this opportunity to work on this Mars lander," she said.

Madsen agreed that the focus on the mission helped the team to almost ignore the Earth-bound schedule of the city around them. "We live kind of in our own world, because everything that is important to us takes place on Mars," he said.

Earth-bound again

Even those who have thrived on the Martian schedule must eventually come back down to Earth. The fatigue shown by the members of the Pathfinder and MER missions at the end of a few months shows that "the team [only] seems to be able to do this for a limited period of time," Bass said.

"I think that in the beginning, right after landing, the enthusiasm was at an absolutely fever pitch. Adrenaline was coursing through the team for quite a bit of time," as the first images came in and the components of the lander were moved for the first time, she added.

But eventually as the weeks wear on, and the mission moves forward, "there are less dramatic surprises, and less anticipation of a particular event," Hudson said. The number of applause-worthy events starts to become more spaced out.

Eventually, "one realizes that this is also one's life, that one needs to be able to sleep and eat and interact with family," Bass said.

Phoenix's primary mission comes to a close at the end of August, and the team was set to return to Earth time for any possible extended mission. They'll actually make the switch earlier than expected, on Aug. 1.

The decision to switch earlier was made because right now the team's Mars time schedule coincides with local daytime, making the switch easier, according to Phoenix robotic arm co-investigator Ray Arvidson of Washington University in St. Louis. The team has become efficient enough now to make command decisions during the day, regardless of what time it is for the Phoenix lander, he added.

Barger plans to publish results from her data collected during the two months that the Phoenix team has lived on Mars time sometime in 2009, and says they could help inform whether future missions will live on Mars time.

However, as the switch date draws near, neither Madsen nor Hudson is concerned about coming back down to Earth.

Hudson said he wouldn't mind staying on Mars time for longer, but that it will be nice to have the chance to hang out with friends who live in Tucson without first having to check and see if he'll be asleep.

Madsen agreed: "I don't think [living on Mars time] has been a big deal, but in a way it's nice to know that when you are [on Earth time], to know that you'll be on the schedule of Tucson local," he said. The switch back will be especially nice for him, he added, as he will be taking two weeks off to explore the area when his wife comes to visit, since he has mostly only seen Tucson and the mountains that surround it in the middle of the night.