Martin Tomasko

We proposed for DISR, the Descent Imager Spectral Radiometer, for this Titan entry probe mission. The deal was, Cassini and Huygens were a joint U.S.-European mission. The Americans were going to be primarily responsible for the orbiter—they had two-thirds of the experiments on the orbiter, and two-thirds of the vote on how the orbiter payload was going to be distributed. The probe was going to be mostly the responsibility of the European Space Agency. They got two-thirds of the instruments and two-thirds of the votes deciding the payload.

I had an instrument on the probe, so I knew that was going to have a heavily European flavor, and I thought it was important for us to get some European co-investigators and get a strong European participation. Peter Smith, who was here working with me on things in those days, and I went to Europe. I remember tramping around France and Germany visiting various places and trying to draw out interest in being a collaborator on this experiment that we had in mind for this European entry probe.

Peter Smith

This was fun because we were Americans on a European mission. But we were worried that without European partners, our proposal wouldn’t be attractive to the European judges. We didn’t know any Europeans. Back in the eighties, there weren’t very many Europeans in planetary science; they were mostly in astronomy. That’s totally changed today.

We went to the Paris Observatory one fine day, up on a hill—it looks like an old palace. There’s a big dome that astronomers used back in the seventeenth century. It’s really an interesting place. There’s a small building back in the trees and a big lake next to it with fish jumping.  Totally different from American science; this was dripping with tradition and charm.

We met Michel Combes and presented our proposal to him. We said, “You guys can help us build the instrument, and in exchange you can participate in the full science of the mission. We think you should build an infrared spectrometer.”

As soon as we made that proposal, they all broke into rapid French. Marty and I couldn’t understand a word. It was too fast. Everybody talking at once—this is the French way. It turned out, for the lab to take on our project, everybody had to agree. If one person didn’t agree, they wouldn’t do it. So several scientists over there had to choose our project over the other possibilities they had. That’s why they’re taking this quite seriously.

Eventually they said, yeah, they thought this could be a good project, and they’d probably be interested in helping us write a proposal. So we said, “Great. We’ll count you in.”

Then we flew up to Germany. We drove way away from all the big cities. At that time Germany was East and West.  Within about two miles of the Wall, in the middle of a cow pasture, there was a brand-new, modern building. That was the Max Planck Institute for Aeronomy, out in the middle of nowhere.

We met this fellow that we’d heard studied comets, which at least was in the solar system. His name was Wing Ip. His response to our project: “I have no interest whatsoever.”

Oh, my gosh. What do we do now? “Is there anybody else here?"

“Well, there’s one guy who sent a camera to Halley’s comet in ’86. Try him. His name is Uwe Keller.”

So we went out to see Uwe Keller. Now, Uwe Keller, unlike Michel Combes, is bigger than I am, bald-headed, and very aggressive. He says, “Yes, we’ll do it. We’ll provide the detectors.”

“Great.” We have no knowledge of Uwe Keller, but off we went.

Now we had two Europeans. We wrote the proposal, and then I became the project manager after we won. We had Lockheed-Martin building it. I’d never managed a hundred thousand dollar project much less a twenty million dollar contract, with Marty’s help fortunately. We had a lot of learning to do as we built this instrument.

Lyn Doose

The big break came when we won the Descent Imager Spectral Radiometer experiment, which was the camera on board the Huygens probe. It was a spectrometer and a specialized camera to look at the Sun to determine the aerosol properties, and covered visible, infrared, violet and some of the ultraviolet.

Cassini was launched in ’97. I was primarily responsible for the software. It was really interesting software; it was adaptive in nature, so that if something happened in Titan’s atmosphere, the instrument would respond to it. At the same time, I wasn’t just an instrumentalist. We published papers along the way; we became experts in radiative transfer. We became one of the first groups that could really interpret photometric observations, and spectrometric observations of planets with thick atmospheres. We published a number of papers on Jupiter and Saturn based on the Pioneer results, and also on Venus, with the Pioneer-Venus results.

So we were well situated to analyze the Cassini-Huygens data when it came back, and it finally did in 2005. Things didn’t quite go the way we expected. The probe spun backwards from the way it was supposed to go. The probe oscillated a little more than we expected it to, and it went outside the tolerances. It made the data much harder to interpret than it would’ve been otherwise. But we’ve done it and actually we’re about to publish what we think is the definitive paper on Titan’s aerosols.

The highest moment is when I got up on January 14, 2005, and turned on the TV and already there were pictures from our instrument, sitting on the surface of Titan, showing these pebbles and this kind of dry riverbed. Obviously we had made it. We had landed on Titan. It was just unbelievable.

Jonathan Lunine

Cassini, of course, is a very large planetary mission. The goal is to explore Saturn and its rings, its moons—especially Titan, a large moon with an atmosphere—and the magnetic environment of Saturn. The mission came about in part because NASA was planning a mission to orbit Jupiter after the Voyager missions, and it was natural since both Voyager flyby spacecraft went on past Saturn that they would plan the same thing. The twist, though, was that the Voyager flyby of Titan turned out to be so interesting, and Titan turned out to be such an interesting place, that not only was the U.S. interested but Europe became interested.

It was a very straightforward collaboration, to get the United States to build a Saturn orbiter, and the Europeans to build a Titan entry probe that would be carried to Titan by the Saturn orbiter. The entry probe would go through Titan’s atmosphere and make measurements. That was Cassini-Huygens. By the mid-1980s, the general architecture of this mission was well-developed. There was a lot of fine-tuning of the political process so that both the European Space Agency and NASA would get going at the same time. That’s tough, because if NASA wasn’t interested, ESA couldn’t be interested, and if ESA wasn’t interested, NASA wasn’t so interested, so they had to move together.

The metaphor that vividly I remember was a balloon launching from the U of A mall, where there were like 15 or 20 manned balloons, and they were all launched. I think they don’t do that anymore at the U of A, probably for insurance purposes. You know, when a balloon takes off, it takes off. But there were these two balloons that they decided to tether together and have them take off at the same time, which was quite a stunt. Of course you can’t have one balloon get too much above the other balloon, because they’re tied together. So one balloon has to go up, then the other, and these go up in a stair-step fashion and it takes a lot longer to get to altitude before they finally cut the rope from each other and let each other go.

It was that kind of really delicate process that was required to get Cassini going in 1989-1990. A lot of us here at LPL applied for different roles; I applied for the role of Interdisciplinary Scientist, which was not someone who would build instruments, because I was mostly a theorist, but somebody who would have responsibility for a science area. I proposed for Titan’s surface, and would use instruments to understand in a holistic way what Titan’s surface was like, which was one of the big mysteries left over from Voyager.

That was my first really big proposal. It got me involved officially in Cassini. Prior to that, the mission was being studied, and ESA and NASA could involve scientists on an informal basis in the studies, but once the mission becomes official, scientists have to actually compete to get on the mission. Some well-known experts on Titan who I know didn’t get on that mission, and my career would have been totally different if I had not gotten selected.

But I did get selected, and I was later selected as well for the radar team, and I was also selected as part of the team for one of the probe instruments. So three different responsibilities. It involves a lot of travel, a lot of learning about mission planning. Just by going through that bottleneck, that narrowest point in the hourglass of getting selected for Cassini, it opened up a whole lot of things.

The launch was in ’97. It arrived at Saturn in 2004, in July, and that was just about 21 years after my first contact with the scientists planning Cassini. Now we’ve got just floods of data. The probe worked as it was supposed to. It was a real risky part of the mission but it worked. We’re getting lots of radar data; I don’t have time to work on all the data I’d like to. We’ve got several other people at LPL with major instrument responsibilities. In spite of all the attention that’s given to Mars, I’d often like to think that Cassini was an important, formative experience for this laboratory.

For the probe mission, as an Interdisciplinary Scientist, I could float around as instruments got their data back from the probe mission. I made sure I was in the porta-cabin where the imaging data came back. That was probably the most emotionally intense of those experiences, because the imaging data were received on the ground. There was a two hour period while those data packets were extracted from other kinds of data that came back from the probe in the same stream and then sent to the porta-cabin where Marty Tomasko’s camera team was located.

Once the data was on their computer, their software converted these to images, and the images were first displayed as a set of 300 thumbnails. That was the way Bashar Rizk, who was the guy in front of the computer consul, was displaying them—one second per image. So for about five minutes you looked at these 300 images, not in descent order. They were in random order, so you could see flashes of things on these thumbnails that looked like something you couldn’t recognize and then a river channel would pop up, and then something you couldn’t recognize and then a fracture would pop up. It was such a bizarre way to see these. Here were the first close-up images of Titan and the last close-up images that we’ll probably see for 20 years, all in that five minute period. That was very intense; there was a lot of screaming in that room and I was one of the people screaming.

Alfred McEwen

My major project right now is called HiRISE, the High Resolution Imaging Science Experiment on the Mars Reconnaissance Orbiter [MRO]. I’m the Principal Investigator of that. LPL is a good place to be a Principal Investigator of instruments, and whole missions, in fact, these days.

I have co-investigators at a dozen different institutions—more than that, now—scattered around the country and in Switzerland, for one. There are various elements to the operation and the software development, some of which is being done at other institutions. I have to coordinate all that, although my formula for being a successful PI is to hire good people and make yourself completely dispensable in all areas, if possible.

I had a lot of experience with the active parts of missions, but none at all with the part of building instruments. There was a fellow at Ball Aerospace named Alan Delamere, who I got to know on a proposal for a global orbiter. He builds instruments and particularly comes up with concepts for instruments.

He needed a PI, and he called me up and asked me if I wanted to do it. It was a surprise to me. I went away and thought about it for a while, but I finally decided if I didn’t do it I’d be kicking myself forever, so I had to do it.

MRO is an orbiter, in a polar orbit. It goes around Mars about thirteen times a day. This is a big spacecraft. The two previous—three previous, including the Europeans’—successful Mars orbiters have been much smaller spacecraft. This one is quite a bit bigger and more capable, in order to carry big instruments like HiRISE, which is 65 kilograms.

It also has a very large high-gain antennae, three meters in diameter, which means we can send back lots of data, which is essential for missions like HiRISE. It’s got a big solar array, so there’s lots of power. There are other instruments, there’s lots of data rate, so it’s a very capable instrument. Months ago, MRO had already returned more Mars data than all the previous Mars missions combined.

It’s a huge amount of data, and it’s very high-quality data for science. It doesn’t get the attention from the news people as the landers and rovers, because people relate to those. But for the science community, this is really the scientist’s mission.

To me, that most exciting moment was getting our very first images in-flight—pictures of the Moon and of some stars. They’re not that exciting images—we were a long ways away from the Moon—but I knew what it meant. I knew that it meant our camera was working. 

Robert Strom

We launched our second mission to Mercury, an orbiter, in 2004. So about a 31-year hiatus [since Mariner 10].  I never thought that would happen. I’m involved with the MESSENGER mission which is on its way.  I’m just hoping I live long enough to see it go into orbit. We’ve only seen 45% of the surface, so 55% is unknown territory. We’re going to go back and image that and see what’s there, so there’s a lot to find out about Mercury.  In fact, it’s the least known planet in the solar system. I want to see the rest of Mercury before I die. I do want to see that, because I’ve been waiting for over 30 years to see the other part of it.

Editor’s Note: MESSENGER completed its first flyby of Mercury on January 14, 2008. It will orbit the planet in 2011. Dr. Robert Strom recalled his first glimpse of Mercury’s far side on Arizona Illustrated on March 12, 2008: “I got tears in my eyes. That first look—after waiting so long—it was very, very emotional. This is a whole new planet. We have to look at the whole thing again.” 

William Boynton

The mission I’m associated with mostly now, the Mars Odyssey mission, was one where we finally got to send the gamma ray spectrometer back to Mars that didn’t make it because the first one [Mars Observer] blew up. In this case, they actually said that if I thought I could build a better instrument than Martin-Marietta—which was now called Lockheed-Martin—then I could go ahead and build my own design. In fact we came up with what turned out to be a much better design, and we built it ourselves, right here across the hall in this lab in Tucson.

It was a pretty elaborate project but we got a darn good instrument out of it, and made some interesting discoveries. We discovered vast quantities of ice buried just beneath the surface that nobody knew was there. Some people suspected there might be a small amount of ice just filling the pore space between the sand grains, but what we found was that it was mostly ice with just a little bit of dirt mixed in with it, rather than the other way around. That really changed people’s thinking about Mars.

We also found some interesting things going on with the atmosphere. One of the people working with me, Ann Sprague, was looking at the argon data. Argon is a rare gas that’s in the atmosphere but it doesn’t condense out at low temperatures, whereas the carbon dioxide that’s in the atmosphere does condense out at low temperatures, and that’s what makes the seasonal frost that happens in the wintertime there.

What she found is that the argon was being enriched over the poles in the wintertime, because a significant fraction of the atmosphere would move toward the winter pole, and the CO2 would condense out, and more atmosphere would come to replace it, and every time more atmosphere comes to replace it, it brings with it more argon. But the argon doesn’t condense out so we were just building up a concentration of that argon.

I looked into the data to see that, indeed, it looked like that was happening, but Ann, who’s got more background in studying atmospheres, looked at the data and she’s been processing it and found out that it’s really telling us interesting things about the motion of the atmosphere on Mars.

Originally when the instrument was proposed, it was thought it was going to be mostly a geochemical instrument mapping the elements over most of the planet. But it turned out I think probably the discovery of the ice and looking at what goes on with the argon in the atmosphere—it’s been surprising that the instruments turned out to be probably as valuable or maybe even more so in ways that we didn’t even contemplate or proposed. I think the fact that we discovered ice in the polar regions probably helped NASA decide that we really need to go with the Phoenix mission, which is going to go to this polar area.

William Boynton

I was involved in a mission called Mars Polar Lander that was supposed to land in 1999 in the south polar region of Mars. I built an instrument for that very similar to the TEGA instrument that we’re building for Phoenix—in fact it had the same name. At the time that mission was proposed, nobody knew about this ice beneath the surface, but by the time we got around to proposing for the Phoenix mission, [Mars Odyssey] had discovered this ice not much before that. It really got an awful lot of interest both from the public and from the scientific community.

I think that helped NASA make that selection, because we were proposing to fly the exact same kind of lander that crashed in 1999. NASA was clearly reluctant to fly that same lander again. But enough people studied the 1999 event that they were pretty sure they’d figured out what went wrong, and they solved that problem, and we made the case that probably no spacecraft has been looked at in more detail than this one we’re proposing because of all of the studies on why it crashed and so on and so forth. In the end NASA decided to go with the Phoenix mission. A lot of people have suggested that the discovery of the ice probably really helped NASA make that decision.

Peter Smith

In 2002, two things happened. One, we were thrashing around trying to figure out if we could use the ’01 spacecraft which had been sitting in a box at Lockheed-Martin, and if so, what could we use it for. What instruments should we include, and what would its scientific goals be? We were looking for a low-cost solution to the Scout dilemma of providing new, exciting science within a cost cap.

The Phoenix mission is shaped like a tabletop with an arm, with some instruments and a weather station—that’s it. You can’t put wheels on it, and you can’t do other daring things, because you want to keep the cost low.

At just the time we were thinking about how use the ’01 spacecraft, Boynton announced that there was ice under the soil of the polar regions. Big coincidence. To me, that was it. NASA’s theme is follow the water, and no spacecraft had ever gotten anywhere close to water. Where they had landed, there hadn’t been water for three billion years.

I thought, here’s a chance: You could just land anywhere in the polar region, and ice is under you. You don’t need wheels. Our mission is vertical. Phoenix is looking at what’s happening today. Ice is not ancient. We want to look at modern structures and modern processes. Is there any chance the ice did melt, and if so, was there biology? All of a sudden, it clicked. I’ve been awfully lucky.  Things have clicked several times for me. You’re lucky enough to have that happen once or twice in your life.

We really worked hard to win that proposal. Of course we did win, because here we are in the midst of the mission. When we wrote the proposal, one thing I insisted on against tremendous resistance was doing the operations here. That’s why we got this building [the Phoenix Science Operations Center]. I convinced the University to agree to provide us space. My feeling was the science expertise is at the universities. The students are here. We’ve got access to all kinds of resources that scientists need.

Michael Drake

I think winning the Phoenix project was perhaps the biggest excitement, in part because it’s the first time a major space mission has been controlled by a University once it’s on the surface of the planet. It clearly has had a very large impact, from a public perception point of view, on the University of Arizona—in fact the University is marketing itself world-wide around the Mars Phoenix mission, simply because we’re going to have an international press pull here. It’s a great opportunity.