An Interview with Marc Rayman, Project System Engineer at Jet Propulsion Laboratory (JPL)
Meet Dawn's Project System Engineer Marc Rayman.The following interview took place at the Jet Propulsion Laboratory (JPL) in Pasadena, California on May 22, 2006 between Marc Rayman, Project System Engineer for the Dawn Mission (JPL), and Education and Public Outreach team member John Ristvey from Mid-continent Research for Education and Learning (McREL)
JR: You work at the JPL as the Dawn Project System Engineer; what does that job title mean?
MR: Well, what I do on Dawn, which really for me is what is so fun about working here, is I get to become involved in just about every technical facet of the mission. My primary concern is: How does everything fit together to make the mission work and to get our science data back from Vesta and Ceres? So, I’m involved in the design of the spacecraft, the design of the mission—that is, what are we going to have the spacecraft do—and the design for how we’re going to execute the mission: how we’re going to command the spacecraft from Earth; how we’re going to build and test the spacecraft; how we’re going to launch it; how we’re going to collect science data at the destinations, and what we’re going to do with those data. So, for me, it’s really cool because, again, I get to participate in all aspects, which is truly very rewarding. I’m extremely interested in the big picture of space missions, and it’s extraordinarily fun for me to be able to see all of the different details and then try to pull them all together to make sure they work in concert because, obviously, it doesn’t do any good to have a spacecraft with no way to get it to the asteroids, or a concept for how to travel to the bodies we want to study but a spacecraft that isn’t capable of accomplishing such a journey. And so, what I work on is this integration of all the different pieces of the project, and that’s what I enjoy so much.
JR: I’m sure you have a talented staff of professionals who support you and support the mission on the engineering side. Since you’re involved in all aspects of the mission, will you tell us about some of the support you receive from the systems engineers you work with, and how that interaction takes place?
MR: That’s a good question. There certainly is a tremendous range of skills that people bring to the Dawn project—really to any space mission. One of the people that I work with has been designing trajectories for interplanetary spacecraft since before I was born. That’s what this gentleman does, and he’s fantastic at it! He wrote some of the essential software tools that we use for developing the trajectories, and he’s been doing similar work at JPL for more than 50 years, and that’s what he wants to do.
Now, there’s another person I work with who is truly an expert in the properties of xenon: how it behaves under high pressure and at different temperatures, and the rate at which it flows through the xenon feed system, which is the system on board the spacecraft that transports the xenon from the main tank to the ion thrusters. He knows everything that you would want to know about the behavior of certain gases under certain conditions.
Now neither one of these folks really is particularly interested in what the other does. I happen to be interested in both topics, so I think that’s a good example of bringing together these individual areas of expertise. The trajectory fellow doesn’t really need to know anything about the properties of xenon, and the xenon expert doesn’t need to know anything about inter-planetary trajectories. And, I don’t know as much as either one of them does about his own area of expertise, but those two people, plus myriad others, combining their knowledge is what makes this all work. And that’s wonderful for me because it’s an opportunity to learn more and more all the time about all these different areas and, again, to pull it all together.
JR: Tell me your role in orchestrating the teams and sub-teams to solve problems.
MR: Well, my role is, in some sense, to be like the conductor for this symphony. I have to know enough about each individual area that I can collaborate, ask the right questions, and guide the work so that it’s applicable to the specifics of the Dawn mission. To take an example at a ridiculous extreme, the trajectory analyst can give us a trajectory to get us to Venus, but we don’t want to go to Venus. We want to fly by Mars, rendezvous with Vesta, leave Vesta, and then rendezvous with Ceres; and there are many issues that come up elsewhere in the spacecraft that may constrain how we want to design that trajectory. He doesn’t know, for example, about the details of how the ion propulsion system works—the system that’s going to propel us to those bodies—so, I have to make sure that his trajectory design work is consistent with how the ion propulsion system works. And, the fellow designing one of the electrical units on the spacecraft knows a great deal about how his electronics work, but I’m responsible for making sure that the way that box performs fits in with what we want it to do in the mission. And so, the enjoyment for me is delving into each of these disciplines, bringing to it what I know about other areas of the project, and making sure that the work all fits together. It’s that ‘fitting together’ that I’m responsible for.
JR: How is your job important to the mission’s success?
MR: I would observe that everybody’s job is important for mission success. In fact, I think many people during the stand-down period of the mission late last year and early this year mistakenly viewed there to be a concern about the ion propulsion system that was somehow out of proportion to the concern about other sub-systems on the spacecraft. And, while ion propulsion may be the coolest subsystem we have, mission success requires everything to work. So, it won’t do us any good to have an ion propulsion system that functions correctly if the thermal control system on the spacecraft doesn’t behave as it’s supposed to—or attitude control, or telecommunications, or the science instruments, or the ground data system, or anything else. Everybody gets to make a contribution that’s important to the success of the mission. Whether it’s somebody who’s responsible for providing an electronic circuit, or a valve, or welding two parts of a propellant line together, or determining how large a heater should be, or calculating the trajectory for the rocket from Cape Canaveral up to low-Earth orbit, everyone of those people has to do his or her part right in order for everything to fit together and work effectively as a whole. To me, that’s one of the things that’s so amazing about space missions. People think about these fantastic pictures that you get back from deep space—and they are fantastic—I’ve loved them my whole life. But, I think it’s also impressive to think about these projects as an accomplishment of humankind.
It really does take a tremendous number of skills to make it work and, in fact, people think of this as requiring scientists and engineers. And, it does. But it requires more than scientists and engineers. Without secretaries, for example, we couldn’t get our jobs done. I travel a lot. And it really would be extremely burdensome if I had to make every one of my own flight reservations, and my hotel reservations, and get a car, and process my own reimbursement requests. That has to happen in order for me to do my job and for a lot of other people to do theirs. We have contracts that involve millions and millions of precious taxpayer dollars between NASA/JPL and private companies and universities, and money is spent in a wide variety of ways, so we need lawyers to oversee and protect those expenditures. We have business people here at JPL who are also responsible for contracts, not just understanding what the laws are, but how you go about following those laws in order to have a contract that protects taxpayers, accomplishes what we want to accomplish, and still allows the recipients of that contract money to protect their interests. It doesn’t do Orbital Sciences Corporation any good if we propose a contract that follows all the laws but hurts them so much that it’s not in their business interest. There are many, many different skills that come together, and they’re not just science and engineering. In fact, I don’t know what your personal background is, John, but we have education and public outreach. I think a highly appropriate use of the taxpayer dollars that are going into Dawn is educating and informing the public of what we’re doing. It’s their money and, in my view of this as being a noble and exciting undertaking of humankind representing our best values, it’s important to share that with the rest of the world so they know about it. And, it takes people with still another skill set to accomplish that, and we’re fortunate to have you bring such skills to this project. In fact, I am very concerned about the scientific and technical illiteracy of our country and many people’s inability to recognize or accept the difference between solidly based science and pseudoscience, so I believe the sort of work you do is a very important element of the Dawn project.
JR: Very good. I want to go back in time just a little bit here.
MR: To the ‘Dawn’ of the solar system?
JR: Not that far. Tell us about your role in the successful Deep Space 1 mission and how that experience is important for Dawn.
MR: You may have to stop me from going on too long, because Deep Space 1 provided truly some of the highlights of my entire life! I was one of just a couple of people responsible for the formulation of the New Millennium Program, which gave rise to Deep Space 1. Then, I worked on Deep Space 1 from its very earliest days, when it was just the briefest of concepts, all the way through the design, development, fabrication, testing, launch and the execution of the primary mission. And then, I stayed on through the extended mission and what we called the hyper-extended mission. I started out as the Chief Mission Engineer; after launch, I was the Deputy Mission Manager, then Mission Director and, ultimately Project Manager. So, I was able to participate in every aspect of that mission, which had many important and exciting accomplishments, including the first use of ion propulsion in an interplanetary mission.
That’s not just collecting a bunch of hardware, calling it ‘the ion propulsion system,’ bolting it on a spacecraft, and shooting it out into space. Ion propulsion is so different from chemical propulsion. We had many problems to solve or questions to answer such as, how do you incorporate this system into a spacecraft? We have built many spacecraft with chemical propulsion systems, but ion propulsion is really so different that it affects the design of the spacecraft, and it even more strongly affects the design of the mission. As you probably know, with conventional propulsion systems, you operate the propulsion system for a few minutes or maybe an hour or two during the entirety of the mission; whereas, for ion propulsion, we thrust for months or years at a time. Well, how do you design a mission that can sustain this powered flight—that can be thrusting for years at a time? And, how do you design the trajectory that delivers the spacecraft to the destination? There are quite a few subtle issues there that needed to be solved before a space science mission would rely on ion propulsion.
One of the objectives of Deep Space 1 was to test ion propulsion to protect subsequent missions from the risk of being the first ones to use such an exotic, albeit very promising, new technology. And so, my experience on Deep Space 1, both discovering and contributing to the solution of those problems, is very valuable on Dawn. And, I feel very lucky to have played an important role in doing that. It’s very gratifying to see it applied now to a mission that has such ambitious and exciting objectives as Dawn does.
JR: Tell us a little bit about how you interface with Orbital Sciences Corporation?
MR: In my view, it doesn’t matter whether the person I’m working with is employed by and resides at Orbital, or JPL, or Los Alamos National Laboratory, or UCLA, or anywhere else. In my view, we’re all part of the same Dawn team, and we all have the same goals. So, if I need to talk with somebody who is responsible for the Star Tracker, that’s a person at Orbital. Since he’s not down the hall, I usually communicate with him by the telephone or by e-mail; whereas, if it’s somebody who is responsible for the small deep space transponder, that’s someone at JPL, so I usually talk with him in person. But to me, there really aren’t any other important differences than that. I don’t think of having to send a message to Orbital. I think of having to send a message to Ken or Joe or Mike or Dom. They may happen to have their offices at Orbital, but we’re working on the same project. I travel to Orbital frequently, so I know some of those people almost as well as I know a lot of the team members at JPL. I enjoy working with them and so, I don’t really see a substantive difference between the way I work with them and the way I work with people here. And, in fact, while I still prefer to walk to someone’s office, e-mail is so common; it’s not that unusual for people in adjacent offices to send e-mails back and forth. So, the fact that the people at Orbital physically are 2200 miles away often isn’t that different from the people who are 22 feet away.
JR: Well said. Let’s go back to the Dawn mission. What do you think is the most fascinating part of the mission? All the pieces and parts?
MR: That’s easy. I think the most fascinating thing about Dawn is the opportunity to explore two completely unknown worlds. In my view, Vesta and Ceres are among the last unexplored worlds in the inner solar system. What can be more exciting than viewing a whole new world?
I love missions that go to Mars, and I think the discoveries there are tremendous. At the same time, in the context of solar system exploration, we know at a very good level what Mars looks like. We may not know a great deal about its internal structure. We may not know what’s underneath that rock over there, or the mineralogy of that structure over there, or what the fissure over there looks like close-up, and there are many exciting surprises yet to be found on that planet. But exploring a whole new world, to me, is really wonderful. That was one of the rewards for Deep Space 1 because, in our extended mission, we obtained the best views ever taken of the nucleus of a comet. I felt like we were introducing Earth to Comet Borrelly. We saw sights that no being—no human being anyway—had ever seen. And at Vesta and Ceres, there will be the opportunity to see many such sites. These are alien worlds that have never been viewed in any kind of detail. The views from the Hubble Space Telescope, while tantalizing, are not really very revealing. And, I think many people mistakenly think of asteroids that we’re going to as little chips of rock. I wrote about this in my first entry of the Dawn Journal. We’re going to worlds. Ceres has nearly 40% of the surface area of the United States. Think about how varied and beautiful the vast lands of the United States are. And, to think we’re going to a place that has a significant fraction of that area. What are we going to see there? It’s going to be fantastic! And it will be unlike anything we’ve seen before. It’s not going to be like Mercury or Venus or the moon or Mars or these little flakes of rock—Eros, Gaspra, Ida, Itokawa—that spacecraft have visited. It’s not that it’s better or worse. It’s different. It’s a new place in the cosmos. And, I think the most exciting thing, at a very visceral level, is going to be to see what those places look like.
At another level, I think the most exciting thing is going to be, what do they tell us about the dawn of the solar system? This is the reason we’re going there. We’re not sending these spacecraft out into space just because we’ve got a little over 2,000 pounds too much material here on Earth, and we want to get rid of it. It’s an exciting adventure that I think really connects with the fundamental human drive to explore. But I want to explore not just what space looks like—I want to explore scientific questions. Such questions about the origin and early evolution of the solar system I find genuinely fascinating.
JR: Outstanding. OK. we’re going to go to the ‘dark side’ now. What do you think is the riskiest part of the Dawn mission?
MR: There are many risks in the Dawn mission. Probably, if you asked me on a different day what the riskiest thing was, I’d give a different answer—in part, because my job requires me to worry about many different things, and today I might be worried about something different from what I worried about yesterday and what I’ll worry about tomorrow. But, I think, perhaps the easiest way to express the riskiest thing is simply—and I shouldn’t use the word ‘simply,’ because this is all very complex but is related to what I talked about earlier—everything has to work together. And, I think the riskiest thing is that some little problem that we either didn’t appreciate, or we didn’t even recognize, or we recognized, appreciated, and didn’t deal with adequately, or even a problem that could never really be expected to be found yet, nevertheless, manifests itself, will prevent the successful operation of everything else. Again, everything has to work for us to get all the way to Vesta and Ceres and get the science data back. And, in my view, it really is remarkable how many space missions work well.
Of course, there have been many space missions. The first one was October 4, 1957, Sputnik 1, so it was a long time ago—48 ½ years. But, despite there having been many spacecraft, there haven’t been many spacecraft that have gone far from Earth and really explored new places. I don’t know whether we really have as secure an understanding as we may think of what it really takes for those missions to be successful. All missions, all missions, encounter unexpected problems, and we try to design the spacecraft so robustly that for almost any kind of problem that could come up, we have some way of dealing with it. We either have two of every unit on board, or we have the capability of reprogramming the software, or we build things so robustly that, through whatever means, they can survive a problem. And yet, new problems always arise, and they have to be dealt with in unexpected ways. I marvel at missions that succeed and I’m not that surprised at missions that don’t succeed.
We are pushing humankind’s capability to its limits with these robotic emissaries that we’re launching into the cosmos, and sometimes they don’t work. I think it’s usually just because of some small problem. And, if not for that one problem, the mission would have been wonderfully successful. I don’t know on Dawn what one such problem might be. So, I think the riskiest thing is that there may just be a little thing that could prevent everything else, which was so well-engineered, so well thought through, from working. I hope that doesn’t happen, obviously, but I can’t say that it won’t.
JR: Will your job change post-launch? And, if so, how?
MR: My job definitely will change post-launch, but I don’t know how. The project has been so focused for the last few years, and will continue to be for at least the next handful of months, on getting to launch and planning what we will do after launch, that I don’t know what my role will be in actually executing what we do after launch.
JR: Now, nuts and bolts. Tell me a little bit about what your everyday work is like. In the office today, for instance, after the interview, what’s your typical work day?
MR: My typical work day consists of spending the whole day looking forward to getting to the things that I planned to do when I came in that morning [laughing], and often I get to them late at night or end up doing them the next day. I have many balls in the air, and some of them are ready to be caught and tossed again, and others are making a nice, long, gentle arc so I don’t need to devote attention to them right away. And so, I split my time, spending some of it looking at detailed data from the fellow generating the trajectory, and sometimes I’ll just do my own analyses on those data to try to understand various questions about the trajectory, and then guide him on what the next analysis to do is. Then, I’ll shift my attention from that to worrying about how air that’s trapped inside the spacecraft, while it’s here on the surface of Earth, leaks out as the spacecraft—while attached to the launch vehicle—ascends through the atmosphere. And, whether that air leaks out at a rate that is acceptable given when we want to activate high electrical power devices, and we don’t want to have a spark inside.
Then, I’ll go to meetings where we may discuss questions like how long to, as we say, ‘bake out’ the spacecraft: that is, seal it in a vacuum chamber and raise it to a high temperature in order to drive off contaminants before launch. How long do we need to spend doing that, based on analyses of what the unwanted chemicals on the spacecraft are and the rate at which they will be driven off various spacecraft surface? So, I spend a lot of my time in what I call ‘working meetings’ where perhaps one person who needs guidance will present a summary of the problem he or she is facing, or collectively, we need to make a decision on which of several options we’re going to choose. And then, a lot of my time is spent talking to people about their specific disciplines—as we discussed earlier—to make sure all these different pieces are fitting together and that everything is going the way it should. I think a lot of people think of a meeting as an activity in and of itself. To me, a meeting is just a forum for working out a problem. I actually enjoy working meetings. I don’t enjoy meetings in which it’s obvious nobody is paying attention to what’s going on, but I like the process of people coming together, sharing their technical perspectives, and applying that to resolve a technical problem.
JR: Tell about your leisure activities. I know you mentioned yesterday you are a photographer.
MR: I am an avid photographer. Well, I have many interests. I love dancing! Every Friday night, I go dancing. I’ve been doing that for a very long time. I met my wife in a folk dance group, and I’m very fond of that. My longest hobby has been the learning about the exploration of space, and I have an extremely large collection of space information and memorabilia. I have files on space activities of about 50 countries. I also have interests in many other areas of science. I’m especially fascinated by the connection between particle physics and cosmology (that is, the origin and evolution of the universe), and so I spend time studying that. I’m an avid outdoors person. I like backcountry skiing, backpacking, hiking. I enjoy astronomy as well. My cats are named Milky Way and Regulus. Those are a few things.
JR: You keep busy. I don’t how you fit them all in. Tell me about some of the education you have had in your career path that led you to become an engineer.
MR: I didn’t become an engineer until after I got out of school. I have a Bachelors degree in physics from Princeton University, where I focused on astrophysics and cosmology. I did my Masters in nuclear physics at the University of Colorado in Boulder and my doctorate in laser and atomic physics and experimental special relativity at the Joint Institute for Laboratory Astrophysics in Boulder—my thesis advisor just won the Nobel Prize for physics this last year.
I used to look down my nose at engineers. My interest is in the science. But I mentioned that my lifelong hobby was studying the exploration of space, and I came to realize, at some point, that I could get paid to pursue my hobby. And so I made a carefully considered decision to stop doing scientific research and transition to being an engineer. But that allows me to bridge the gap between the scientists and the engineers because now I can speak both languages. I appreciate and understand the science, and yet because of the combination of my hobby and my ability to apply what I learned in physics to engineering problems, I can work as an engineer. That has worked out very well for me.
JR: You’re an engineer; you’re a scientist; you’re a very good writer, as is evidenced by the work that you’ve done in the Dawn Journal and other things; those skills don’t always go hand in hand, as you probably know. Tell me how your job involves communication skills, the importance of those skills, and communicating with people of varying and different expertise.
MR: That’s actually what’s interesting; my job certainly does require good communication skills and one of the reasons is what we talked about earlier. That is, I have to help the people with different areas of expertise on the project fit their work into the larger Dawn mission. And I often find that I wind up—it’s almost as if I speak different languages—when I speak to the trajectory people, I speak in their lingo, their jargon. And when I speak to the mechanical engineering people, I speak in their jargon or their language. Words may have different meanings to different people, and so I need to be able to talk to people in each area in a language that they understand even if it’s not the way that an expert in another area might understand it. So, when I talk to the trajectory engineer and the mechanical engineer at the same time, the trajectory engineer will hear me using phraseology for the mechanical engineer that isn’t quite familiar to him, even though I’m talking about the trajectory because I’m putting it in a language that will allow effective communication with the mechanical engineer and vice versa. And, of course, trying to integrate all these disparate areas means that people have to have common understandings and that is done through communications. That certainly is an important part of what I do.
Then, there’s a completely different aspect of my work where I deal with communications and that is that I’m fortunate enough to work with some of the education and public outreach people in communicating to the rest of the world what it is we do. Sometimes I am embarrassed being at talks from people—that is, technical people who give presentations to the public—who have the most wonderful material to work with and yet can’t make it comprehensible and exciting. And yet, it all is comprehensible and exciting, if communicated in the right way. And so, I’m lucky to be able to work with the education and public outreach people to help the rest of the world understand what it is that we’re doing on Dawn and why that’s so cool. I hope that contributes in some way to helping the public appreciate a little more about real science, because, as I mentioned, I am distressed about many people’s poor understanding of science. Those are important uses for communication skills.
JR: Thank you. You certainly wouldn’t think of it as multi-lingual but you really are—the jargon, the lingo...
MR: In fact, the first time I became aware of that was when on Deep Space 1, we had a visitor from NASA headquarters who was in a discussion with me and with a trajectory specialist: a person who was an expert in the computation of trajectories, and that’s what he does for a living. The person from headquarters was a high-level manager and didn’t have time or the background to learn the details of that field. He was asking questions about the trajectory, which I was answering, while I was also talking with the specialist. Afterwards, the trajectory engineer, who is also a friend of mine, made some comment to me like, ‘I was really surprised at how you switched between talking at these two different levels.’ I realized that it’s very similar to someone who could translate to allow the person speaking Basque and the person speaking Icelandic to communicate.
JR: That’s good. One last question. If you had to give some advice to students, or to anyone pursuing a field of study in science, what would that be?
MR: The first piece of advice is that you have to choose a field of study that you’re interested in. I’ve had friends whose parents forced them into fields that they did not find rewarding, and the ultimate consequence of that is what you’d expect; they either wind up with jobs they don’t enjoy, or they wind up making late changes in their career. So, because, as I mentioned earlier, so many different skill areas are required to make a mission like Dawn work, I think people should follow their interests. And, if it happens to be astronomy, or condensed matter physics, or electrical engineering, or chemical engineering, or business management, or software design, or the field of education, whatever it is, pursue that and—it may be trite—but do the best you can.
I personally also think that—this actually is not quite an answer to your question but I’m going to offer it anyway—that is, I think there’s something to be said for breadth in education. I mentioned that my Bachelors degree was from Princeton University, and I took a huge amount of math and physics there and loved every one of those classes. But the reason I went to Princeton, and not one of the other schools at which I was accepted, was because I felt it was important to have a broad education. So my Bachelors degree is not a science degree—Princeton calls it an ‘AB;’ most places would call it a BA—but it’s a Bachelor of Arts degree. When I matriculated there, I promised myself that I would sample at least one new department every semester. I’m glad that I did because I don’t know of anything more exciting than the exploration of space, but there are a lot of other things that are almost as exciting, and it’s nice to be exposed to those as well.