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Mars Exploration Program

Martian Diaries

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My Life on Mars Time
By Bobak Ferdowsi

Curiosity's Beep
This image shows what the beep looks like once Curiosity sends back a confirmation to Earth that she received the information of what she will do on Mars for her current sol (Martian day).

As I write this, we're in the morning of Sol 25, with our very healthy Curiosity rover sitting in Gale Crater doing a variety of opportunistic science today. We've just uploaded the daily sequences (our set of instructions for activities Curiosity must perform).

Let me begin by describing a typical day for Curiosity and me. Curiosity works during pretty normal hours (though maybe she wakes up a bit late), so typically most of the Martian day's activities take place from about 11 a.m. to 3 p.m. This is so that 1) we have daylight for driving and taking pictures, etc. and 2) so we get our most critical activities done by the afternoon, when we talk to our two orbiting assets, Mars Odyssey and Mars Reconnaissance Orbiter. The key there is that those orbiters give us much better data rates than our own smaller antenna to Earth (which is good, but takes a lot of power and time relatively speaking to get the same information back), and they get it back to us before we finalize completely what we're going to do the next sol (sol is just the word for Martian day). The result is that we know how Curiosity is doing and how well she did on yestersol's (yesterday's) activities before telling her the plan for the current sol.

Once we have a plan, teams work to flesh out the details - modeling times, power, data volume, temperatures, etc, to make sure it's a safe and doable plan, then finally proceed to deliver the sequences in a format Curiosity can understand. Around this time is where I'll show up to double-check the sequences and confirm that the activity is 'go'. Once we all concur the activity is ready, a smaller team, including myself or one of the other Flight Directors, will work with the Deep Space Network to deliver the sequences to the rover. Once onboard, Curiosity lets us know she's got it by sending out a little beep. On some days, we have longer back-and-forth conversations with the rover (called 2-way commanding) for activities where we want a ground team to evaluate the success of each step before proceeding to the next. That's not too common for most basic things, but it is often used for more complex activities and for some first-time events. Then in the afternoon, data comes down, and the cycle begins anew.

Bobak Ferdowsi
Flight director, Bobak "Mohawk Guy" Ferdowsi, has tribute to the rover's "footprint" as it spells out JPL in Morse code.

One of the more interesting aspects of all of this is that a sol (Martian day) is about 40 minutes longer than our day. That means if we line up our time of day at 9 a.m. here and 9 a.m. for Curiosity on Mars, the next day at 9 a.m. for Curiosity, it's 9:40 a.m. here, and the day after that, 10:20 a.m. So you can imagine within a couple of weeks, 9 a.m. for Curiosity is 9 p.m. here! It makes for some strange hours at work. The whole team is working "Mars time" so we all end up having crazy stories about eating dinner at 8 a.m., and finding things to do when we're off work at 4 a.m. One of our families spent the entire last month on Mars time and discovered many of the 24-hour establishments in the LA area. It also means I am sometimes trying to sleep during the day, so I wear an eye-mask and ear plugs to sleep better. I personally like going for long bike rides at night, since I have the whole road to myself.

I'm actually writing this at the end of a long day, I got in around 3 a.m., and it's now 11 a.m. here (but 11:20 a.m. for Curiosity), so I'm going to go take a nap!