The Martians Are Here!
An interview with NASA systems engineer Nagin Cox
Nagin Cox is a Systems Engineer- Tactical Mission Lead at NASA’s Jet Propulsion Laboratory in Pasadena, CA. She helped land the Curiosity and other rover vehicles on Mars, and she helps manage the exploration and research done by the rovers from NASA’s lab on the ground.
She also gave an amazing talk on our stage this year about the difficulties of living on Mars time. The Martian day is 40 minutes longer than a day on Earth, and the rover shuts down during the Martian night to save power. So, for three months at the beginning of a mission, the engineers and scientists on Earth live in a different time zone. Forty minutes may not sound like much, but by the end of the work week, Nagin’s schedule is about three and a half hours off from her family; after two weeks, she’s seven hours off, coming home from work in the middle of the night.
We had a chance to talk with Nagin about what it’s like to work on two different planets. She also told us a little bit about how space exploration is an unexpected microcosm of global cooperation for the greater scientific good.
Tell us a bit more about what living on Martian time is like. What is the impact on the scientists who work on these projects?
There’s a very large impact on the families involved in these projects. In 2004, there was a couple working on opposite rovers: one on Spirit, one on Opportunity. The rovers had the same mission, but they landed on different parts of Mars, so local noon was different; the timing of the two rovers was almost 12 hours apart. Jeff and Cindy literally passed on the freeway, one shift ending and the other starting. Their kids did not see both parents together, awake, for three months. We also had a single parent, a father with a toddler.
Daycare doesn’t work on Mars time; what happens when you’re going to work in the middle of the Earth night? What do you say to the daycare?
People are aware of the schedule digression that the military keeps. Military families know that signing up for forward missions involves separation, shift work, etc., but that’s not a typical part of an engineer’s work and it’s not something people are prepared for. It’s not that people are unwilling, it’s just that you’re there for a limited time, so that’s something I wanted to expand upon — the impact on families who haven’t signed up for this military environment, unlike careers where you know that’s part of it. It’s not something the community around them is very able to adjust to. (On military bases, they know there are spouses and families who are without a member.)
Does NASA help families cope with things like childcare?
There’s a lot of resources put toward recognizing the impact on the families of scientists. There’s a lot of discussion about it; every mission asks itself whether it’s really necessary to do Mars time, and every mission we get better at coping with it. There’s definitely a learning curve, but now — we have sleep researchers, we ask if our tools have improved, if we can make this easier— it’s part of the mission design. It’s a trade-off, because of the efficiency Mars time gives you for operations.
How much are you currently involved with the rover on Mars?
As is typical at this stage in a mission, I’m part-time on the Curiosity rover. I come in and do shifts on Curiosity, like many of us, because we’re also involved in building the next rovers.
The next American rover will be in 2020; there’s a European rover sooner than that. There’s a mission going in 2018, called Insight, to look for Mars quakes.
It gets really crazy before launch, but we’re also involved in long-term development. There’s a project called ARM, the asteroid redirect mission, that’s for planetary defense. That mission doesn’t launch until 2021.
Tell me more about your specific position.
I’m one of the tactical mission leads. When I’m on shift, I’m the lead of the entire process.
We have three very strong roles: The downlink lead and their team determine whether all the activities on Mars the day before went correctly, what is the health of the rover at this time, etc. The uplink lead and their team are responsible for asking, What should we do tomorrow, or “nextersol,” on the Rover? Those two activities happen in parallel. Then there’s an advance planning team. They make cautious plans, saying, if things keeps going the way we expect, this is what we’ll do in three days.
I’m in charge of all three teams. The downlink team gives an initial report, then they have another hour or two to download and analyze all their data and give a full report to the uplink team. I make the calls based on those reports.
There are days when things don’t go as expected. My role dramatically expands trying to get things back on track, fighting fires, helping the team manage an unexpected occurrence.
Unexpected occurrences happen on Mars, just like they do on Earth; our mission was designed to last two years, but we’re in our fourth year, and the drill is getting a little sticky and not drilling quite as expected — experiencing predictable mechanical problems. If you’re on duty the day that happens, then you’re the one to step in, to bring in your experience and pick up the slack. I’ve been through these things before, so I’m able to say, “Okay, let’s give everyone time to figure out what they’re seeing, and I’ll put a constraint on some things for the day,” or, “I think we’ll figure this out quickly, so we’ll go ahead as planned but with extra caution.” It’s a judgment call about whether, for example, to use the robotic arm.
It is very fun, I have to say. I adore my job. I also like getting missions ready to launch, but my 14-year-old self wanted to operate missions. There’s a difference between working on something that’s going to launch, and a rover that’s actually on Mars, exploring. Those are the “pinch me” days. That’s something to enjoy every day.
Can you tell us about the different kinds of missions?
There are landed missions, and there are roaming missions, and they’re very different.
Imagine that you were driving to the Grand Canyon, and you were going to go to one spot and stay there. That’s your view, and it won’t change, so you can plan observations in advance with a good amount of certainty. That’s a landed mission.
Now imagine you had a car, and you were going to drive around the Grand Canyon, but you had no guidebook and no map. Every day is non-deterministic; you don’t know what you’re going to do the following day until you’ve experienced the current day. That’s a roaming mission.
During these missions, when we’re on Mars time, we have to learn to command the rover very quickly, so that we can get the data down from the last “sol” (or day) when the rover goes to sleep, determine the plan, and get the commands up to the rover before she wakes up for the next sol. That’s why we have to work the Martian night shift, and work very quickly; there are three teams working on each mission.
How do you decide where to land the rover, and what terrain to equip it for?
There are two major components to this.
Basically, we have these “orbiters” that have these amazing cameras. Thanks to them, we have a preview, because the data from the orbiters is very high-resolution (a little like Google Earth). They give us really good ideas of what the terrain is like. There are American, European, Indian, and other orbiters, and that data is very valuable.
In terms of where should we pick — it takes five to seven years to pick the landing sight. As soon as a mission is given the green light in terms of funding, people start thinking about the logical place to land.
We just had our first landing site workshop for a human mission, which isn’t scheduled until 2035. Scientists from around the world come and make their case.
These meetings are especially important for landers, like the quake detector mission planned for 2018. Seismologists attend those workshops and present a case for the spot they think is best, based on the mission’s objective, and over the years, they are whittled down to the finalists.
The engineers are at these meetings to help evaluate the safety of the landing sites, based on terrain and access to the solar power that helps power the rover. As the spacecraft gets built and its capabilities become clear, we may need to reevaluate the feasibility of sites. Engineers are getting better at landing — by Curiosity, we were able to let the scientists pick between the final four locations, where in previous decades the final choice was up to the engineers. (They were shocked!)
We want to land at the best place; it doesn’t matter if the person who suggests that location is from Russia, Vietnam, or the U.S. Nobody wants to send a multi-million-dollar, one-time mission to the wrong place. It’s an amazing example of international cooperation around science and engineering.
What about the instruments that go on the rovers — how do you decide what to send into space?
The process for instruments is similar to that for the landing site: ideas come from around the globe and are chosen on merit, regardless of country of origin. We have requested good ideas for an instrument to go with the 2021 asteroid redirect mission from scientists all over the world. If you can demonstrate that you can build it on time and reliably, and you can operate and fly it, then you’re in.
The opportunities to fly are very limited, so whoever’s going, people try to get their instruments on those missions, and we need to select the best options. NASA has instruments going on other countries’ missions as well.
Spain, Russia, Canada, and France all have instruments on the Curiosity rover. Sometimes it’s a trade — we’ll give you the instrument for free if you give us a ride to Mars, or help pay for the launch vehicle, etc. It’s really rewarding to work in a field that’s about what you’re doing more than the politics of where you’re from.
What a wonderful example of global cooperation.
The data from the Rovers is available worldwide. Anybody can go to the Curiosity site and look at the images that came down yesterday. We do this for all humankind.
When I wrote my TEDxBeaconStreet talk, I wanted to include all this information, because I want people to understand the many levels of planning and cooperation that go into these missions. Unfortunately, it doesn’t fit into twelve minutes, so we lost the context, but I’m glad I could provide it here.
