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Planetary News: Cassini-Huygens (2004)

A Conversation With Bob Mitchell Cassini Program Manager On the Mission, the Rewards of Gardening, and the Pure Joy of Indian Motorcycles

Robert Mitchell was born in Springville, Pennsylvania. He graduated from the University of Arkansas, in Fayetteville, and holds masters' degrees in electrical engineering and mathematics. Since joining JPL in 1965, Bob has worked on trajectory design, mission design, and navigation for planetary exploration projects such as Mariners 5, 6, 7, and 9, and on the Viking mission. From there, he moved to the Galileo mission, serving as design manager from 1979 to 1988, during which time he led the development of numerous mission redesigns when the launch date slipped from January 1982, to eventually launching in October 1989. He also led the team that developed the innovative Venus-Earth-Earth Gravity Assist (VEEGA) trajectory to give the spacecraft the velocity boost it needed to reach Jupiter, and went on to manage JPL's mission design section from 1988 to 1993. Bob returned to Galileo to manage the science and sequence office until 1996 when he was appointed Project Manager of the mission. Two years later, he accepted the dual-role of Program Manager / Project Manager of Cassini. He is a recipient of NASA Exceptional Achievement Awards and has also earned a NASA Outstanding Leadership award.

AJSR: You have a rather unique dual-role on the Cassini mission -- serving as both Program Manager and Project Manager, would you explain how that came to be?

BM: Some programs are made up of several projects -- the Mars Program, for example -- while the Cassini Program only has one -- the Cassini Project. I suppose this is because it's a rather large project, and also because there really aren't any other projects now that are similar enough to fit well in such a program. The Program Manager role carries some extra duties, but in this case, the distinction isn't very significant, so I don't normally think of this as a dual role -- I'm just the manager.

What is a typical day for you as the Cassini Program Manager?

A typical day involves coming in at about 7 in the morning, going through the email, and returning whatever phone messages may have accumulated overnight. The email ranges all the way from routine meeting notices to issues from scientists about their budget to issues with people wanting permission to do one thing or another with the spacecraft, various tests or activities.

Schedule related topics always take up part of the day. I have a staff person who maintains the schedules and keeps them coordinated and aligned. But there are always issues where problems are applying pressure to the schedule to slip something, and of course financial issues have schedule implications. I get probably an email at least once a week -- sometimes once a day -- from one of the science teams or one of the internal engineering teams needing more money, so that's a decision. Although for where we are now, things have pretty well settled down and stabilized. The budget is pretty much intact and in place and people understand what it is, and what our flexibility is or isn't. So those kinds of communications probably come up less frequently now than they used to.

I spend a lot of time in meetings. Meetings generally are of two types -- one is where there is an issue that requires a decision and another is just general communications where the staff is together, a regular weekly scheduled meeting, or a special ad hoc meeting for communication purposes. And frequently, I will sit in on meetings if for no other purpose than staying current. I like to know what's going on. In fact, I will frequently sit in a meeting and throughout the course of the meeting never say a thing. The value of meetings like that for me is to understand what's going on, what the issues and problems are, although questions frequently come up at those meetings that I end up responding to.

So you're basically Cassini's grand central clearinghouse -- everything comes through you -- whether it's a problem of science, engineering or an issue involving money?

Yes, although at some level I try to keep myself out of it. With the different managers on the program who handle the different areas -- one is the spacecraft area, one is the mission support and services area, one is navigation, and another is the science and sequencing area -- the managers at those levels are, fortunately for me, very capable people. I try to give them as much autonomy as is practical. My involvement comes when there is something where it's not clear what we ought to do or if there are interactions between different areas, where they have some disagreements about priority or allocation of funding, then I get involved in that. But on a day-to-day basis, I generally try to stay out of it.

It sounds like you actually do a lot of listening -- ?

Well, I hope so. In terms of understanding exactly what different peoples' problems and challenges are, and the consequences of whatever course of action we might take, I have to listen, and listen well, and listen for both the spoken, as well as the unspoken word, to understand really what the issue is.

What's the most difficult or most challenging part about being Program Manager?

Probably it's allocating the science part of the budget. Our budget is less than what it would take to do a full-up, complete job, but it's still a lot of money and we're going to do an excellent mission with it. So I have established priorities for how we allocate funding. The engineering activities tend to get higher priority than do the science activities, because they are absolutely essential precursors to being able to do the science. We have communicated these priorities to the science members of the team and they generally agree that they are the right priorities and that we have allocated the funding at least approximately right.

Allocating funding for the engineering part of the mission is fairly straightforward: you evaluate what has to be done and what it takes to be certain that it's going to get done right and fund it to that level. The rest gets distributed among the science teams. So it's the science teams that tend to come up short. Understanding exactly what their needs are -- and understanding when you're getting sandbagged a little bit versus getting a completely candid and honest assessment of what's needed and distributing the funds accordingly -and making the right decisions is probably the most difficult part of my job. I worry that I might not have the right insight and one team might be being treated poorer than another team.

On the flip side, what is the most rewarding aspect of being a program manager?

Saturn Orbit Insertion (SOI) was a good moment. I felt a lot of personal pride and accomplishment in that although it obviously was very much a team effort -- it took a lot of work on the part of a lot of people to make that come off the way it did. But I think the most rewarding part probably is the day-to-day activities where things go right, especially now that we're getting science data coming down on a daily basis. Images are put up on the monitors and people look at them and say -- 'Wow! Look at that!' Just seeing the expression on peoples' faces and hearing the tone of their voice when they look at an image or some results and have a reaction -- and knowing that we -- jointly as a team -- have enabled all that, made all that happen -- that's probably the most satisfying thing.

How would you compare/contrast Cassini and Galileo, the last two of the so-called 'big missions?'

My position to be evaluating each is a little different because when Galileo was doing the full-up prime mission, I was in one of the lead office roles -- like what I described to you previously for the Cassini managers as opposed to being the top manager -- so my perspective of things was a little different.

On Galileo, we did our probe insertion and our orbit insertion all within a 4-hour period. That was also a very rewarding time. I remember in the mission support area. I wasn't there. I was over talking to some media folks. But I was watching the people in the mission support area on a monitor and saw them watching the signal from the orbiter -- which was going to tell whether the probe had worked or not, whether they had gotten a signal. It was delayed by a minute and half or two minutes beyond what we had predicted it might be and they were looking awfully concerned. It was very obvious when the signal came in.

Yes, I remember. I was there in Von Karman, covering it for OMNI magazine -- it was a magical night, wasn't it?

That was a big moment. That whole event was really something.

In terms of comparing Cassini and Galileo, one thing that comes immediately to my mind is that the teams -- the people -- were / are just really great -- strong, capable, real team players on both of them. When I was told that I was going to get the Cassini job, one of my first reactions was-'Gee, I wish I could take this Galileo team with me over there to do that' -- realizing of course that wasn't going to happen, but knowing what a good strong team it was. When I got over here and got to know the Cassini folks a little better, I realized they were just as good as the Galileo team, and in some cases, maybe a few who are even better, so we have had just an exceptional team of people on both projects.

The Galileo mission was quite similar to Cassini in the sense that it had a probe, an orbit insertion, a tour, and satellite encounters, but the pace of things on Galileo was considerably less. For one thing we had the much-reduced data volume because of the failure of the high-gain antenna and our having to use the low-gain antenna. For another thing, we had 10 satellite encounters in two years on the Galileo prime mission, so the navigation -- getting from one to the next, which we thought was a big deal at the time -- in hindsight now was relatively relaxed. On Cassini, we have 52 satellite encounters in four years, as well as 76 close passes of Saturn compared to Galileo's 11 close passes of Jupiter, so the pace is quite different.

I've heard that every minute of Cassini's calendar is booked for the entire four-year tour?

It isn't quite done to that level yet, but in another few months it will be. That's another difference between Galileo and Cassini. For all its outdated technology, by today's standards, and all its problems, Galileo was a very capable spacecraft, and in some rather obvious ways a more capable spacecraft than Cassini. We didn't have to do quite so much advanced planning on Galileo just because of those capabilities. But on Cassini, primarily because we don't have a scan platform -- and because all the instruments are bolted solid to the spacecraft meaning we have to turn the whole spacecraft to point the instruments -- means there's a lot of competition between the different science teams and the different investigators in determining who gets to control pointing of the spacecraft, who gets to observe with their instrument at any given time.

That competition for the spacecraft resources is what has driven us to lay out this timeline so far in advance, because there are all of the negotiations, all of the horse-trading and agreements that have to be made. We came to realize years ago that the only way we had any prospect of being able to pull off these sequences once we got into orbit was if we started laying this thing out well in advance. We began that process about three years ago.

Galileo and Cassini also share good old NASA redundancy, so the chances are good that no study would be lost, no minute wasted?

Yes, we fully expect that to be the case with Cassini. Just about every engineering subsystem on this spacecraft -- and the same pretty much was true on Galileo -- is redundant, so any failure we might have, we simply switch to the other, backup system. Now of course one thing with the design of Galileo was that the high-gain antenna and the tape-recorder provided redundancy for data return. After losing the high-gain antenna we relied on the tape recorder to make the mission possible. It was a reduced mission, but not by near the factor it would have been without the tape-recorder. Then the tape-recorder just about failed.

I remember that well. That was a scary moment.

Oh it really was. We figured that thing was a goner when it happened. With some very careful planning and rework and reprogramming, we were able to make the limping tape-recorder work and we got the data back. But we almost lost both parts of what was intended to be a redundant capability on Galileo.

For Cassini right now, all the subsystems are still fully redundant and it's looking good for us.

That redundancy certainly has to give you a confidence that you can't get in other kinds of missions. As we move out of the era of faster-better-cheaper how do you think exploratory missions should evolve now if we are to continue a decent pace of exploration?

I think having some smaller, quicker missions is good. That's not to say necessarily that the entire better-faster-cheaper concept was without its flaws. But to have missions that can go quick and get the return back in hand so the same people can see the mission all the way through is a plus, and to be relatively inexpensive is good. The concept with that approach is that you can, and will, lose one every once in a while, because you don't have all your eggs in that one basket -- and of course when we do lose one it's still kind of a big deal even though that was part of the concept. I think that concept's okay. There is a place for that. But I do think we need to continue to have a big mission every so often, because there are things that you can do with big missions that you just cannot do with smaller, faster, cheaper type missions.

Look at Galileo and Cassini. There's a proposal now to send a spacecraft to Jupiter to do a different kind of science survey that is in the New Frontiers class. New Frontiers is a relatively new class of projects that NASA is now developing and accepting proposals for. There were, I think, seven proposals submitted, and two accepted for further study. The intent is that next May, one will be selected from those two that will then go on to be developed and be an actual flight project. The cost cap on those is $650 million or something like that. There's a mission in that set that goes to Jupiter and does an interesting, worthwhile, scientific mission. But it is not going to be near the mission Galileo was, because Galileo was able to study the satellites, the planet itself -- its atmosphere, magnetic field, gravitational field, the entire environment around Jupiter, all of the plasmas and fields and particles, satellites, even Jupiter's ring (although we didn't do much on that). Now this Jupiter mission coming up in the New Frontiers class is primarily going to focus on the internal part of Jupiter -- the gravity field, the magnetic field, and the external magnetic environment in fairly close to Jupiter. It's a very focused and specialized kind of mission, so it's obviously worth doing. But in terms of getting a complete picture of the Jovian system, where you get both the spatial and temporal variations you need to put together a complete picture -- a simpler mission like that just can't do that.

The same can be said for Cassini. You could take some specialized area of study -- maybe the atmosphere for example -- and fly a spacecraft that would go and focus in on the atmosphere of Saturn, but if you want to understand the entire system, then it takes something like a Cassini or Galileo class mission to be able to do that.

Anything in particular you're hoping to find or looking forward to most before Cassini wraps her tour?

Well, let me qualify my answer by saying that I'm not a scientist. My background is engineering and my more recent experience is management, but that doesn't keep me from having opinions about the science of this mission. The thing that intrigues me the most about all this is Titan -- the only moon in the solar system that has an atmosphere. It's not the biggest moon and there are 3, or 4 or 5 that are comparable in size and gravity and in their ability to hold an atmosphere -- so why only Titan? And furthermore, that atmosphere is almost all nitrogen, which is what Earth's atmosphere is mostly made up of. So what's going on? What is so unique, so special about Titan? Things like what's going on dynamically, internally with the smaller satellites, the rings and the dynamics of those are all interesting, fun things I'm anxious to hear about. But if I had to pick one and say that's where my curiosity is piqued the most, it would be Titan.

I think you're not alone on that one.

I think not.

How do you spend your down time -- in other words, what do you do when you're not getting spaceships out to other planets?

Well, where I live, my house has a fairly large lot and so I do quite a bit of gardening and landscaping. I do my own yard work. I don't have a gardener. In my neighborhood, I can only think of one other house besides ours where they don't have a paid, come-and-do-it-for-you gardener. But I just find that enjoyable, relaxing, and therapeutic. And when you're all done and the roses are blooming and the grass is green and the weeds are gone, that's rewarding.

Then the other thing I do -- I probably shouldn't tell you about this one because a lot of people tend not to understand it -- but I kind of like it --

Well now you must tell --

I have a garage full of old antique motorcycles --

Antique motorcycles -- you don't have an Indian by any chance do you?

I have four Indians.

Which is your most precious?

That would have to be the 1940 in-line 4 cylinder model. So far, I have entered it in three shows and have taken three best-of-show awards with it. About half-a-dozen magazines have done articles and photo shoots on it.

Wow! A true American classic -- and famous to boot!

[Ed. Note: Before Harley-Davidson rose to the motorcycle pinnacle, an Indian, manufactured by the Indian Motorcycle Company of Springfield, Massachusetts, was the motorcycle to have.]

Who'd have imagined you were into motorcycles -- is this a holdover from your youth?

Yeah, I suppose so. I first had a motorcycle when I was a senior in high school and the bug kind of came and went and I rode off and on throughout my life. But as I got older and kind of outgrew riding, I got to where I am now -- mostly working on them, restoring them and taking them to shows. I ride them occasionally, but not very much.

Many people recognize Harleys, if only because of their sound, but those Indians, I bet they cause a certain set of people to salivate when you take them out -

Yep. For people who know about motorcycles, Indians generate a lot of attention. When I go out riding and pull into a gas station, invariably one or two or three people will come up and say something like, 'Wow I haven't seen one of those in a long time. My Dad used to have one of those -' and on and on and on. It's a good way to get a conversation going.

As conversations go, what has been your own most memorable moment on the Cassini mission so far?

I wasn't on the project yet at launch. When it launched, I was still on Galileo. SOI is very memorable because it is so recent and current and something that I kind of worried about and fretted about for quite some time. Having the whole SOI event, both what happened at Saturn as well as what happened right here, come off as well as it did was a very memorable thing.

Any last thoughts before we go?

In terms of looking forward to what's coming, I think 99 percent is yet to come. We frequently hear now in the last few weeks what great data we're getting and how it's such a successful mission, but the bulk of it is still in front of us. The data in hand so far has not been at all analyzed -- they've only gotten a very perfunctory going over. We've got 44 close flybys of Titan to come, whereas 'til now we've only had one distant one. The icy satellites -- it's anybody's guess what we're going to find on those -- they're all different, unique and not understood. The Huygens probe will be taking pictures all the way down to the surface and we are surely in for some surprises there. For people who think this has been a very exciting mission to this point, and I certainly agree with that, I will say the best is by far yet to come.