While most of us here on Earth enjoy a mere 24 hours in our day, the scientists working on the Curiosity rover at NASA's Jet Propulsion Laboratory are living according to the Mars solar day — called a sol — which lasts 24 hours, 39 minutes, and 35.24409 seconds. So why exactly does the Curiosity team need to live on Mars time, and what's it like to sync your schedule to Mars' when you're still living here on Earth?
We spoke with Scott McCloskey, a systems engineer at JPL, who is working the first of three Mars shifts. The entire Curiosity team has been living on a Mars schedule since the rover landed on Mars a few weeks ago. (In fact, one engineer got his wife and kids living on Mars time as well; you can read about their experience at NPR.) McCloskey spoke with us about challenges and camaraderie that come with living on Mars time, speculates what temporal life might be like when we have colonists on Mars, and explains why he has trouble keeping track of the time:
Why do you live on Mars time?
Scott McCloskey: Basically, it's to take full advantage of the time available to plan what the rover does each day. So, basically as soon as we get the data down from the rover, people will start coming up with what drive to do on the sol and that means you have to be here whenever the rover sends back the data. So that ends up tying you to the Mars time. And then you work starting from that point through until you have to send the commands up before the next day.
How long will you live on Mars time?
I think it's going end up being somewhere between three to six months. It just depends on how long it takes the team to get more efficient about the planning process. I think with the MER rovers, once the first three months of the mission have passed, they switched to Earth time, so I think at that point in this mission people would start to think the same thing. It's a comfortable thing, so once the team is ready, then we'll transition back to Earth time.
Was it difficult to switch to Mars time?
It was very abrupt for me personally. The first day after we landed, I had to come to work at 1am in the middle of the night right after we landed. That was a little bit jarring, because I was pretty much up for a day and a half. But then you kind of get into it. It's actually really exciting to be here and working on this mission, so that overcomes a lot of the tiredness and you're just running on adrenaline. Not overdoing how cool it is helps keep you awake. So it hasn't been too bad in my opinion. And different people handle it in different ways. There's lots of caffeine and melatonin and things like that.
What were the hardest adjustments?
It definitely can make it hard to see other people. My wife will sometimes miss me if I'm working nights. But it also makes it hard to see other friends and do interesting things. When you're awake in the middle of the night, you think, "What am I going to do now? It's three in the morning." There's nothing open and there's not much to do. It does make you feel a little isolated from the rest of the world. Although, when you're here at work, there are so many other people who are also doing it, it's easy to forget that it's the middle of the night. You walk around and there's hundreds of people here. That helps a lot, to be at JPL around a bunch of people who are also living on Mars time.
Have you discovered any advantages?
It's easier to park. You avoid traffic because you're not commuting during rush hour. The parking lots aren't all full. Personally, I'm not really a morning person, so a lot of the time it just ends up being a way to sleep in, which I kind of enjoy. And you can potentially get an extra 40 minutes of sleep a day. You know that feeling where you wish you had more time every day? Now we actually get an extra 40 minutes to sleep or do whatever.
Do you know if there have been any studies on the long-term physiological effects of living on a longer day?
I haven't seen any studies, but I wouldn't be surprised if there were some effects.
I can't help but imagine how this would affect a colony living on Mars. Do you have any thoughts on that?
I think that the Martian colonists would be living on Mars time, obviously. And then there could be something where you have a team of people on Earth who are living on Mars time to follow along with the colonists and communicate with them. So this might be a sort of similar Mars time experience.
Sort of like people in the US who live on Beijing time.
Yeah, it's just a different time zone, but one that shifts. I've heard the joke — I don't know if it's a joke because it's not that funny, but it's interesting — if you were to sit on a cruise ship that slowly traveled west around the world at two-thirds a time zone a day, that would be like living on Mars time.
If you had a rover on another celestial body, would you similarly sync up to that body's day?
I think that would be likely, and you can see that with the other missions that JPL does where people end up working at pretty odd hours not just for the Mars rover but for a lot of other missions just because the orbital dynamics and the physics of the planets don't really change but your spacecraft has to do what it does at the right time. If you have to fire the rockets in the middle of the night or during Christmas, you have to be here. So it always is given priority. It's part of the job. So I would imagine if there were a rover on some other body, people would have to come up with some new, weird schedule shifts to make the best use of the opportunity. It's so rare that we get something on another planet that you want to take full advantage of it.
Are there any other missions that operate on a lengthened day?
Most missions don't have quite as intense a daily planning cycle that I'm aware of. I think the amount of stuff that we try to do on the rover each day — even though it might seem that we're not doing a whole lot, there's a lot that goes into even just driving 20 meters or taking some pictures. I think that's one of the things that causes us to have to be on Mars time.
Are there people who work an inverted Martian schedule?
Yeah, that's one of the things that makes it hard to see some of our friends is that there are people working around the clock. And so, just like if you were working at a hospital, there would be a first shift, a second shift, and a third shift. So I've been working the first shift Mars time, but I have friends who work second and third shift, and so people are here throughout the day and it all kind of rotates around. Like, I have a friend who is basically working the Martian third shift and there's not too many people on the Martian third shift. So most people are here the Martian first shift and second shift.
So the third shift is the Mars graveyard shift?
Yeah, exactly. And that's actually when the rover is executing the commands that we send it. And then the first shift starts when it's done executing the commands.
When you're working the first shift, what time of day is it for the rover?
It would be the afternoon or evening for the rover. So even though we would call it the first and second shift because that's when most of us are working, we're actually doing most of our planning work when the rover is asleep. We try to operate during the day because it's warmer and the warmer temperatures are better for the mechanisms and the cameras work better when there's light to illuminate the terrain. So the rover usually sleeps at night and that's when we're doing most of our work.
Is there anything that has particularly surprised you about living on Mars time?
Just the regular routine of life. Getting to go to restaurants that you're used to going to, maybe they're closed when you're awake. I find most of the fun stuff I do in my life is between five or six pm and two in the morning and when I have to be asleep or at work during that time frame, it sort of cuts into the work/life balance and getting to do other things.
Have you gotten anyone to stay open late to accomodate your schedule?
I don't know of any businesses that have changed their hours for us. There are a couple of places that have done a free Curiosity-themed burger and then we'll get free food at a couple of places, which is nice. But nobody changed there hours. There are a few 24-hour places around here, but you can only go to Jack-in-the-Box so many times before you tired of it.
So do you have a big Mars clock?
There's Mars clocks where we work and some of the websites the team uses have Mars time displayed on them. And there's also a computer program that people have on their laptops that also show Mars time. All the meetings are scheduled on Mars time and it makes it sort of funny to keep track of. It'll start at some random time like 1:13. Nothing happens on round numbers. And hour-long meetings end up being one hour and one minute because the Mars hour is a little longer than the Earth hour.
So what time is it for you right now?
Honestly, I lose track. People have smart phone apps to keep track of what time it is on Mars. There's an iPhone app on the App Store and an Android app. I have a Blackberry because I'm stuck in the past and there's no Mars time apps for the Blackberry and so I have a little bit of a harder time keeping track of what it is than other people.