Once Curiosity lands on Mars, NASA lead flight director David Oh and his colleagues responsible for the rover's operation will be required to live their earthly lives on Mars time. Oh's wife, Bryn, and their three children - Braden, 13, Ashlyn, 10, and Devyn, 8 -- will do so as well, by choice and in the spirit of adventure.

The idea to join in on Dad's time shift was Mom's, and son Braden has started a blog called Marstimr to chronicle their experiences. The three of them agreed to answer a few of my questions via email.

What's the difference between Mars time and Earth time? And what are some of the implications for the mission and those running it?

DAVID: Once the rover lands, it operates on a daily schedule where it works during the day and goes to sleep at night. The engineers on Earth send the rover a new set of commands every Mars morning. To get those commands ready on time for the rover every day, the engineers work on Mars time. Their clock is synchronized with the Martian clock, and moves 39 minutes every day.

BRADEN: A day on Earth is 24 hours, but a day on Mars is about 24 hours and 40 minutes. Anyone on Mars time will wake up 40 minutes later than they did the day before (we get up 8:00 day 1, 8:40 day 2, 9:20 day 3, etc.), and will consequently get an extra 40 minutes of sleep. It's more complicated than that, because the whole day shifts, but that's pretty hard to describe. By the middle of August however, we will be asleep during the day, and awake at night.

BRYN: We have chosen not to add 39 minutes to each day. We will actually add 30 minutes to each day for the first week or so until we start going to sleep after the sun is up. That will both give us the chance to start off "slowly" and figure things out, plus it will give us more time to be awake during daylight hours. Once our schedule really becomes inverted, we'll push our schedule an hour a day, "a time zone a day," to shorten the time we are working against the sun, and to right our schedule in time for school to start. It will also give David the chance to have a week on "normal" time before having to move his schedule again. One way of looking at it is that we'll be going around the world in 30 days.

What prompted the decision to go on Mars time?

DAVID: We want the family to be together on this adventure. And it is an adventure to land on Mars and go exploring.

BRADEN: The family was up for it (we thought about how much fun it would be), so we're all switching over! We will switch August 1, and switch back onto normal time in time for school (or possibly into the beginning of school).

BRYN: David will transition from Flight Director of Cruise Operations to Flight Director of Surface Operations once Curiosity has landed. ... I jumped at the chance to take our family on to Mars time when I found out David would be continuing on to Surface. Building a spacecraft and landing it on Mars is a life-changing experience. I wanted the opportunity to include our entire family, especially our children. There is a sense of adventure, of traveling into the unknown, that accompanies sending a spacecraft to Mars. We will be capturing a piece of that as our family follows the Rover's schedule on Earth.

The challenge was particularly appealing to me. How hard or easy would it be to add a time zone a day to our schedule? What would it be like working against the sun? What happens when you add multiple people, and personalities, to the problem? What does the world look like at night?

In addition, the logistics of supporting someone on Mars time is not trivial. Empirically, I had heard that the engineers who had the most success switching to Mars time on MER (Spirit and Opportunity) were those without families, especially those without children. It is difficult to set up an environment with quiet zones and quiet times that includes children, and it is difficult to prevent a parent from spending time with their awake children when the parent ought to be sleeping on Mars time. I wanted our family to continue in family life -- eating meals together, having weekends together, playing together.

I also had secretly wanted to try a 25-hour day since college.

At the Oh household, what adjustments or accommodations will you need to make in your daily routines?

BRYN: First, we cleared our entire schedule for August, and we've told all our friends. There are no commitments outside of David's work on MSL that we have to meet. We will juggle lessons and sports and doctor appointments to fit our moving schedule. It will make play dates a little tricky. I have to calculate our lunch and dinner times every day. Everything works on paper. We'll have to be flexible when it comes to reality.

BRADEN: We are putting up shades in each person's room to help with light during bedtime hours.

Will you take advantage of any special equipment or software? (I read of a watchmaker making special Mars time watches for a previous mission.)

BRADEN: We actually have a family friend who has offered to make a Mars time clock app for us, but isn't finished yet. Hopefully we'll get our hands on that before too long!

BRYN: There are a variety of ways to count time on Mars, but the Mars team at JPL uses a 24 hour Mars clock where every Martian second is just a little bit longer than an Earth second. Time for (Mars Science Laboratory) is referred to in LMST or Local Mean Solar Time, and is the time at the location of Curiosity's projected landing site.

When the MER team went on Mars time back in 2004, they had special mechanical watches created to display Mars time. Now, we can create iPhone apps. I've got a beta version of an app a friend made for me which includes MSL's time in LMST, plus Earth time in UTC and PDT.

Another very helpful and very cool piece of software is a free Java app called Mars24 out of NASA Goddard and created by Robert Schmunk. Not only can it tell me MSL's current time (use the coordinates Long: 222.60 W, Lat: -4.60 N), it will also calculate any future time I need. Plus, it has a large selection of maps to choose from and will map other vehicles and landmarks from its database. It's also fun to watch the shadow of night move across its globe.

My husband and I recently acquired Fitbits and have used them to track our daily activity and nightly sleep habits. We'll use them to track the effects of Mars time on our activity level and sleep efficiency in August.

Finally, calendaring has been quite an adventure. I started the process in Excel, listing David's start and stop times each day. I have lots of columns: Wake time and day (both in Earth time and Mars time), Sleep time and day since wake and sleep often fall on separate days, equivalent lunch and dinner times, sunrise and sunset, etc. I have a column with suggested activities based on our schedule. It gets a little more complicated in the places I have to maintain two separate schedules - one for David and one for the rest of us. That happens at the beginning and end of August. Once I was happy with the schedule in Excel, I created Sleep blocks in my Google calendar so I can see my schedule on the go.

I'm still considering what time I want to see on my "wrist watch" or house clocks. I may set my phone and some key clocks in the house to display the time zone we are in for the day instead of PDT so that our bodies gets daily cues (e.g. lunch/dinner) from the clocks.

Oh! One very low-tech device we are using is a full length mirrored closet door turned on its side plus a handful of dry erase markers. I plan on posting the upcoming wake/lunch/dinner/sleep times plus David's start and stop times. Maybe I'll add a column that tells everyone how much to set their clocks ahead by, too.

Will you be doing anything else to simulate living on Mars, like eating space rations or closing the shades to simulate the Mars night when it's daytime here?

BRADEN: Hopefully we won't have to have space rations (freeze dried food is pretty nasty), but we are putting blinds up in our rooms. Public windows will remain uncovered. Windows in bedrooms will always be covered in the hopes that it will help us sleep. The covers are removable however, so we could uncover them if we wanted to.

BRYN: We will not be doing anything special to simulate living on Mars -- no space rations, or anything. Instead, we are embracing what it's like to live in a big city at night. Our list of activities include things like: night hikes, midnight dinner at Denny's, visit Hollywood or the Santa Monica pier, teach our youngest to ride his bike in an empty parking lot, see a sunrise, figure out who actually goes to 24 Hour Fitness at 3 a.m. We're definitely interested in other people's ideas, too.

What do you expect will be the most difficult challenges?

BRADEN: Rotating our internal clock. We will have to stay up late and stay in bed even longer. Staying up late shouldn't be a problem for us boys, but staying in bed until wake up will be. It will probably be vice versa for my sister, who doesn't like to stay up at all.

BRYN: I think the hardest part will be staying motivated throughout the entire month. I hear that it's grueling to move your body clock day after day after day. I think it will be especially difficult if any of the children give up. One of my kids has a fairly rigid internal clock, and moving it one day, let alone 30 days, might prove quite a challenge.

I am also concerned about how difficult it will be to work against the sun. At least when you suffer jet lag, the sun is on your side. Studies from MER show that people get cranky on Mars time. Add to that a lack of sunlight, and we might not be the nicest or happiest people to be around.