One-on-One
NASA Engineer Edward Tunstel: Working on Mars Time
By Lango Deen
Feb 6, 2004, 17:38

Dr Tunstel and a model of the rover

"Like many kids," says Eddie Tunstel Ph.D., "my role models were sports figures." Growing up in Harlem, and later in Queens, N.Y., Dr. Tunstel, a senior robotics engineer at NASA's Jet Propulsion Laboratory, spent much of his time playing basketball and football. He was also into hip-hop and drawing and sketching. And he loved taking things apart and putting them back together: He liked figuring things out. Tunstel was going to be an architect, but the engineers on a panel of architects and engineers changed his mind.

But it wasn't until he got to Howard University that he actually put together his desire to do art with the notion of being an engineer. At Howard, he developed an interest in robotics and artificial intelligence: two areas of engineering and computer science that allow him to apply a combination of things that peaked his interest while growing up in New York.

As senior robotics engineer at NASA's Jet Propulsion Laboratory, Dr. Tunstel now leads the mobility and instrument-deployment device team on the Mars Exploration Rovers, Spirit and Opportunity, trying out the moves these machines make millions of miles away in outer space.

We spoke to Dr. Tunstel about art, models, systems, and robots.

USBE: Did you have role models or mentors when you were growing up?
Tunstel: Like many kids, my role models were actually sports figures. It wasn't till high school where I started to have...interest in taking things apart and figuring how things work. I used to do a lot of drawings, and up until junior high [I] wanted to be an architect.... I went to a seminar at the New York Academy of Sciences, and they had architects and engineers on the panel talking about their careers, and I was more impressed with the engineers. When I got to Howard, I said, "Let me put together this desire to do art with this notion of being an engineer." I chose mechanical engineering.

USBE: Tell us about your work.
Tunstel: My main job is to do research. And when we work on a flight project like the Mars mission, this is more of an applied job. We're actually putting something into action based on today's technology. The research part of what I do is looking towards the future and trying to improve the way we can currently do things with robotics.

[On the Mars Exploration Rovers project], my responsibility has to do with the functionality of a certain subsystem, and that is the mobility subsystem, [which] includes the wheels and the suspension that the whole vehicle rides on — the six wheels.

The whole function of the arm is to place instruments where scientists want them to be placed. That means if the scientist see a particular rock or some piece of soil they want to take measurements on with these various instruments, then the mechanical arm can be commanded. Once you give it the position...it can actually, by itself, figure out how to place a given instrument onto that spot. And it does that with three of the instruments on the hand. But there is also an additional instrument that is more like a tool rather than a science instrument. That one is more like a grinder.... It remove[s] any weathered surface that's on top of the rock, for example, that basically covers up any true material that the rock is really made of.

Every subsystem has several teams. There is the team that does the software for the subsystem and a team that does the hardware for the subsystem. So let's talk about the arms as an example. With the arms, you have a set of folks who just write the software. And separately from them, you have a set of folks who design what the arm is going to look like, how it's going to work, what motor it's going to use, and all that sort of thing.

...These folks work more or less independently, but they have to interact when the whole thing starts to come together. The way this happens is once the hardware that is the actual mechanical thing becomes available, and you have motors that are actually moving it, you definitely start to marry that piece of hardware with the software that controls it. And, generally, above all of these folks are another group of people called systems engineers.... These are the ones who make sure that the interfaces between what the people on hardware are doing and what the people writing software are doing match up appropriately.

They also design various sorts of tests that combine the hardware with the software, so that we are sure that it all works, and not only for that subsystem. They also ensure that subsystem [the hardware and the software for the arm] will interface with the rest of the vehicle.

USBE: You're working on Mars time at the moment. How is that working out?
Tunstel: Whichever landing site you're working with, you're working basically according to when the sun comes up at that place; and when it goes down, that's like night time for you. I just finished my day; every day on Mars is about 40 minutes longer than a day on earth. The way that works is every day I start work 40 minutes later than I did the previous day. So eventually, while right now I'm working overnight, in about 15 days...I'll be working during the day. I'm the lead of the mobility and instrument deployment device subsystem. [There are] six engineers doing that job across Spirit and Opportunity, and, as the lead, I start out on Spirit. We try to make sure we get everything going. In fact, today we exercised the arm for the first time, and it's working very well. Once Opportunity lands, one of our guys goes off on that mission, and eventually I come [onto] that system.

USBE: Do you have a personal robot?
Tunstel: I've been building a house robot — pieces of hardware and fragments of software — but the goal is to have something that moves around the house from room to room, brings you things. And if I get to the point where I can make it sophisticated enough, maybe I'll put a little vacuum on it. (laughs)

USBE: What would you say to a kid who wants your job?
Tunstel: Pay attention to the math and science that's been taught, because those are the fundamental pieces that you need. Ask a bunch of questions. I don't know too many of my colleagues who got to where they are without asking lots of questions. Hardly any of us knows it all. One thing that we do very well is learn from each other. Asking lots of questions and studying hard helps in looking forward to similar success.

USBE: What does the success of this mission mean to you?
Tunstel: From the NASA standpoint, it's always about the science. But for me being an engineer, the big part is to see some of the technology that we've developed actually used in environments that we've developed it for. What we'd been doing for a number of years was exercising things in laboratories and stuff like that, but this is the real deal. And now software you may have contributed to, or algorithms [which are the way certain software pieces work] that you might have helped to develop, are in action on another planet. You're seeing how well it works, and for a researcher that fuels the next 10 years for you. You say, "OK, well this is a good benchmark right here. Now I can bounce from this and improve things even further."