Sixth from the sun, the planet Saturn is only now giving up secrets that Joe Burns and his colleagues have waited years to learn.

By Kenny Berkowitz ’81

Sixteen years after Joe Burns started to help plan the Cassini mission to Saturn, NASA’s orbiter has reached its destination, with new data streaming back to Earth every day. It will take years, or even decades, before it’s all analyzed, and as the first papers are being published, Burns sits quietly in his office, juggling his three jobs — engineering professor, researcher, and vice provost — and enjoying the vicarious pleasures of being a billion miles away.

“I love to travel, and this is just the greatest way to go,” says Burns, a professor of astronomy, the Irving Porter Church Professor of Engineering, and university vice provost for physical sciences and engineering. “There’s the elegant beauty of space, the excitement of exploration, the chance to see new things. It’s like traveling to another country, where you’re stimulated by seeing something unexpected and trying to understand how that society operates. From a technical standpoint, Cassini provides an opportunity to tackle scientific puzzles that may have very, very simple solutions. Because we’re surveying this system in detail for the first time, we don’t need to have the answers to the nth decimal place — we just need an order of magnitude. We merely want to understand what we’re seeing.”

With papers piled on the floor, posters of Saturn taped to the walls, and a bicycle leaning against a bookcase, Burns seems perfectly at home in his office, dressed in a T-shirt and sandals, and speaking with a simple directness that makes a lifetime in space exploration almost sound like an accident. One of five brothers, Burns grew up in the then-rural Hudson Valley, and though he was offered a scholarship to Cornell as an undergraduate, his father sent him instead to Webb Institute of Naval Architecture, located on Long Island Sound. (“When my dad learned that I’d gotten into a school that was totally free,” says Burns, “he said, ‘Son, you’re a naval architect.’ So I became a naval architect.”)

Webb was so small, with only 17 students in his graduating class, that Burns joined the intercollegiate tennis team, even though he’d never played before, and became student body president. Through Webb’s required co-op program, Burns worked as a shipyard welder, an engine room cadet on a merchant ship, and a tester of models for America’s Cup yachts. Nonetheless, by the time he graduated, he had already rethought career plans as a ship designer. By then, five years after the Soviet Union launched the first satellite into space and only months after John Glenn became the first American to orbit Earth, the best minds of a generation were turning toward space, and Burns decided to pursue a doctorate.

Coming to Cornell, Burns shifted his focus from fluid mechanics to space dynamics, completing his Ph.D. in 1966 and taking a post-doc at NASA’s Goddard Space Flight Center. Two years later, Burns came back to join the engineering faculty at Cornell, where he found himself drawn into Carl Sagan’s orbit. Over the next decade, Burns became an expert on planetary dynamics, and apart from research appointments in Berkeley, Moscow, NASA-Ames, Paris, Prague, and Tucson, he’s been in Ithaca ever since.

Working with colleagues and students, Burns has discovered numerous irregular satellites in orbit around Saturn, Uranus, and Neptune, sparking research that, since 1997, has tripled the number of known satellites in the solar system; in tribute, he’s had an asteroid, 2708 Burns, named after him. Along with teaching graduate and undergraduate classes in mechanics, applied mathematics, astronomy, and physics, he’s edited two books, Planetary Satellites and Satellites; chaired the American Astronomical Society’s divisions of planetary science and dynamical astronomy; and spent twenty years as the editor of Icarus: The International Journal of Solar System Studies.

As Burns tells it, all this came about through his friendship with various Cornell astronomers, including Sagan — “I was just a space groupie,” he says — which led to Icarus, press conferences, organizing national meetings, space policy panels, chairships, congressional hearings, and ultimately to membership on the CRAF, Galileo, and Cassini missions. But when colleagues describe him, the stories are very different: “Joe has a tremendously broad, encyclopedic knowledge of the research that’s been done in a lot of areas in planetary science,” says Phil Nicholson, professor of astronomy, who’s known Burns for more than twenty years and works as a member of Cassini’s visual and infrared mapping spectrometer (VIMS) team. “His modus operandi is identify a problem and find a graduate student who can make it the nucleus of their thesis. But almost always, it was Joe’s idea in the first place. Many of those students have gone on to become very well known and respected in the field themselves — and they all still talk to him.”

“Joe can handle a wide range of scientific questions on all sorts of matters,” says Peter Thomas, senior research associate, who was originally trained as a geologist (Cornell Ph.D. ’78) and works on the Cassini imaging team with Burns. “He’s a great example of someone who has moved beyond his formal training to become very prominent in the field. Because whatever your background, after working for a while in space, you train yourself to do other things. It’s all about exploration, and when you’re exploring unknown worlds, you learn to adapt.”

Burns’s first mission, the ill-fated Comet Rendezvous Asteroid Fly-By (CRAF), lasted about five years before it was cancelled by Congress, with some of its hardware later transferred to Cassini. On Galileo, his second mission, he analyzed spacecraft images of Jupiter and discovered two new rings, one embedded in the other and both composed of microscopic debris kicked off the planet’s smaller moons. The structures were totally unexpected, and the significance was huge: For the first time, Burns and his colleagues had determined how planetary rings can be continually reborn after they originated, billions of years ago, when the solar system was forming from a flattened disc of dust and gas.

In talking about Cassini, Burns is proud to be associated with the mission’s Cornellians: Nicholson; Thomas; Joe Veverka, professor and chair of the astronomy department; Peter Gierasch and Steve Squyres ’78, Ph.D. ’81, professors of astronomy; and Matt Tiscareno and Matt Hedman, post-doctoral associates who arrived last year. Also on the Cassini scientific team are Mark Showalter, Ph.D. ’85, a doctoral student of Burns’s, and two Engineering graduates whom Burns taught: Jeff Cuzzi ’67, the mission’s leader for studies of planetary rings, and Tony DelGenio ’73, an expert on planetary atmospheres. In describing his part in their collaboration, Burns likes to talk about the solar system’s smallest bodies — satellites, asteroids, comets, and dust — and the evolutionary effects of even the most minute, barely measurable forces, acting over eons. “If my work has a theme, it may be that the world is understandable,” he says. “Even things that at first appear unbelievable can be understood with a little creativity and enough study.”

If the example of past missions holds true, some of the most influential studies from Cassini may still be years away, after the data are all archived, analyzed, and analyzed again. Already, Burns and the imaging team have published their first papers in Nature and Science, with discoveries that have startled the scientific community. New rings have been found around Saturn; new moons have been identified in the gaps between rings; and clouds of oxygen suggest the presence of tenuous atmospheres over the rings.

“Research is a very human endeavor, with a lot of competition that demands a lot of drive,” says Burns. “For the most part, it’s friendly competition, but to some degree, we all want to be the first person to point something out. Nowadays I don’t care so much about publication, but I love to tell people, ‘Look at what we just found!’ It’s not like a steep mountain that I’ve got to climb — I’m old enough now that I don’t need to climb mountains anymore, but I still am excited to learn what’s over that next ridge.”

In its first year, Cassini has captured many tens of thousands more images than the Voyager flyby missions and is expected to send a hundred thousand more before the nominal mission ends three years from now. “In the past, we used to get a snapshot of these rings, just a few pictures that we could stare and stare at,” says Burns. “But now, we get to watch the whole movie, so that we can learn how things change. And because dynamics is what I’m about, if we can see these systems evolve, we can write the differential equations that describe those changes. And that’s fun.”

“Cassini is producing orders of magnitude more data about the rings than anyone has had before,” says Matt Hedman, whose previous training in experimental cosmology prepared him to extract weak signals even when they are contaminated with substantial noise; he is currently working with both Burns and Nicholson. “We’ve been given the opportunity to see things that have never been seen before, things that have only existed in simulations. As a relative neophyte, I’m able to ask Joe or Phil, ‘What does this mean?’ And sometimes they can explain it, and sometimes they can’t — which is especially exciting. I’m learning as I go, and I continue to be amazed at just how complex these systems are.”

“The thing that’s surprised me is just the incredible clarity of these images, and how much detail we can see of some structures that had only been theorized about,” says his officemate Matt Tiscareno, who works with Burns on identifying and unraveling the dynamical phenomenology of the rings. “It’s like being on the front line of exploration and being among the first people wading in and trying to explain all these things.”

For Tiscareno, the wavy edges of gaps in the main rings have a puzzling complexity, raising questions as to how they are generated; for Burns, the latest mystery lies in what generates the kinks of Saturn’s rings, and how to model the dynamical interactions that keep those kinks moving past his camera. Thomas’s greatest surprises have come from the first images of Iapetus, one of the larger satellites of Saturn, which is far less spherical than expected, and has a ridge that’s 20 kilometers high running precisely along its equator, “looking like a walnut, and absolutely no one would have predicted that.” Nicholson, whose VIMS instrument had no equivalent on the earlier Voyager missions, is receiving the first results of the rings’ composition and is puzzled to see that they’re “remarkably homogeneous, unvarying, looking very much like the ideal laboratory spectrum of low temperature water frost.”

There are traces of iron silicates and organics in the mix as well, and any number of possible explanations, with no clear solution in sight. But the biggest surprise for Nicholson comes from recognizing just how far this mission has come from its inception. “We’ve spent 16 years planning this mission in great detail, deciding what observations we could make,” he says. “It’s hard to come to grips with the fact that we’re actually getting brand new data arriving every day now, which is a huge change in mindset.”

For old hands like Burns and Nicholson, finally arriving at Saturn leads to more planning, not less, with increasing amounts of time spent watching others do the hands-on analytical and numerical analyses that first excited them about space exploration. “Sometimes I think it would be nice to have a week to do nothing except bury myself in the data,” says Nicholson. “Because it’s such a long mission, you’d think there would be plenty of time to do things, but there are deadlines coming up every day. And even though we’re getting data now, we’re still in the process of detailed planning for observations that will happen six months or a year from now. So much of the nitty-gritty science is being done by post-docs and graduate students, and people like Joe and I have to get our kicks from vicariously looking over their shoulders.”

The time is especially crowded for Burns, who spends about half of his day as vice provost trying to facilitate the research of other faculty members in the university and claims that his greatest accomplishment as an administrator is “staying alive. My problem is that I try to be involved in way too many things. I’m attempting to learn about, and help, the dozen research centers that report to me, but not willing to pass up this chance to explore Saturn.” He hasn’t given up teaching, or windsurfing, or dinner parties, or an occasional game of basketball. But more often than not, he’s here in his office, traveling by satellite and plotting his next move to gather as much data as he can before September, when the orbiter will shift into the equatorial plane and won’t reach the proper vantage point to study the rings again until May 2006.

After that, who knows? Cassini is planned to operate in Saturn orbit for two more years, and the project might continue for as long as four years after that, but that future isn’t known yet, and doesn’t need to be. “Planetary exploration is great, because it’s not so far out as astrophysics and extragalactic astronomy, where you can say just about anything, because nobody can ever test you,” says Burns. “Here, if you’re wrong, you know there’s going to be a spacecraft someday that will kick your butt. And that makes it especially stimulating— knowing that you have this challenge to predict some things that are only going to be truly understood by those who come after you.”