FEATURE — Fall 2004

Ray Arvidson is the James S. McDonnell Distinguished University Professor and chair of the Department of Earth and Planetary Sciences in Arts & Sciences; the department has a prototype of the rovers now on Mars.

Overseeing Rover

On the Mars Exploration Rover Mission, Professor Ray Arvidson is the University's lead investigator, analyzing and archiving data sent from rovers Spirit and Opportunity—investigating fundamental questions of life and survival in the universe.

by Judy H. Watts

A man whose name, features, and bearing hint at his Scandinavian heritage, Ray Arvidson is an   explorer in the best tradition of Northmen who followed the seas to lands as distant as the South Pole. For Arvidson, chair of the Department of Earth and Planetary Sciences in Arts & Sciences and the James S. McDonnell Distinguished University Professor, the passion for "exploration and discovery" goes hand-in-hand with the practice and teaching of formidable science. And he, too, follows the water—in research treks on Earth, orbiter investigations of Venus, and robotic examinations of Mars that have significantly raised the scientific trajectory of interplanetary missions to come.

"In my Pathfinder Program for undergraduates, we study Earth's environmental sustainability, which depends on water," Arvidson explains. "And our Mars research involves a huge question of sustainability: What happened to the environment? Did life get started? Did it hang on? We're trying to understand past climate, the role of life, the planet's evolution. And in a future mission to Venus—which is like Earth gone wild—an orbiter will search for active volcanism to learn how that planet works. All three planets are natural laboratories for studying global climate and climate change. Everything in my research and teaching fits together, and the sustainability of life is a central theme."

The NASA Mars Exploration rovers Spirit and Opportunity function as robotic geologists--an artist's rendering portrays a rover on the surface of Mars.

Director of the Earth and Planetary Remote Sensing Laboratory in the McDonnell Center for the Space Sciences at Washington University, Arvidson has worked for more than 30 years with the National Aeronautics and Space Administration (NASA). His research focuses on planets' surfaces, which he characterizes through imaging and other observations. His remote sensing focuses on visible- to infrared-wavelength regions; from his measurements he infers textural and mineralogical information.

With superb graduate students and the "brilliant and enthusiastic" undergraduates in the Pathfinder Program in Environmental Sustainability—which he helped develop and leads—Arvidson invariably heads for places where few have gone before. Fieldwork on environmental change in the Mojave Desert, Death Valley, northern Canada and Greenland, Antarctica, and Mauna Kea in Hawaii, help us understand planetary surface processes. At the same time, the research experiences inspire stellar young scientists to continue the journey.

"Ray Arvidson is one of the most dedicated of faculty members," says Chancellor Mark S. Wrighton. "He spends a great deal of high-quality time with his students, engages them in science, and encourages them to stay involved. He has made the Department of Earth and Planetary Sciences one of the best in the country, and his contributions to science are enormous. He is a University treasure."

On January 3, 2004, Spirit was the first of two rovers to land on Mars. Spirit's landing site was within the 95-mile-wide Gusev Crater, which may have held a lake fed by an ancient river channel. The "postcard from Mars" was taken by Spirit on its fifth day by the panoramic camera; a dust-coated airbag is prominent in the foreground.

The 300-million-mile-high field trip
Of Arvidson's interplanetary science adventures, the most dramatic—to date—is the phenomenally successful Mars Exploration Rover (MER) Mission, under way on two frontiers. (NASA has extended funding for the original 90-day mission through at least September 2004.)

The prime frontier, the focus, is Mars' alien-looking, starkly beautiful craters, plains, and hills. It is a severe, rusty-hued world, with an exceedingly thin and dusty carbon-dioxide-laden atmosphere; winds that reach 80 miles an hour; raging dust storms; nighttime temperatures far below zero—and as Arvidson and his colleagues have confirmed, a watery past.

For spectators back home, the adventure began in two stages, on January 3 and 25, 2004, when NASA engineers and an interdisciplinary team of scientists successfully landed mobile robots, Spirit and Opportunity, on opposite sides of the Red Planet. "The mission is exciting for all of us," says Edward S. Macias, executive vice chancellor, dean of Arts & Sciences, and the Barbara and David Thomas Distinguished Professor in Arts & Sciences. "It is helping to show us where we are in the universe. We're grateful to Ray and his colleagues—and proud to be part of these remarkable times."

While the machines were rocketing through space, Arvidson and mission colleagues selected final landing sites based on safety and scientific promise. The choice for Spirit was within the 95-mile-wide Gusev Crater, which may have held a lake fed by an ancient river channel. Opportunity's site was Meridiani Planum, a basalt plain rich in hematite, an iron oxide that typically forms in the presence of water. The determinations—faultless on all counts—relied on data from the Mars Global Surveyor and the Odyssey orbiters, NASA projects on which Arvidson is a team scientist. (He was also a member of NASA's Viking and Magellan science groups and science coordinator for the 1998 and 1999 Solo Spirit balloon missions of University trustee Steve Fossett, M.B.A. '68.)

As deputy principal investigator for the science on the MER Mission (formally, the Athena Science Payload), Arvidson is also a distinguished visiting scientist at NASA's Jet Propulsion Laboratory (or JPL), in Pasadena, California. His collaborator of nearly 10 years, Steven Squyres, professor of astronomy at Cornell University, is principal investigator. They are responsible for science planning, data acquisition, and analysis during the massive operation, ensuring delivery of the greatest possible amount of the most meaningful science. "We used to compete for grants," says Squyres. "Now we've joined forces!"

Arvidson actually missed Spirit's arrival on Mars. "I had been doing fieldwork in Hawaii with my Pathfinder students, and it was important to finish and return with them. I was on the plane when the pilot relayed the news that the rover had safely landed. We arrived in L.A.; my students flew to St. Louis, and I drove up to JPL." He and Squyres have been working 10- to 12-hour days ever since. "We don't mind," Arvidson says. "We're right in the middle of the action!"

"In my Pathfinder Program for undergraduates, we study Earth's environmental sustainability, which depends on water," Arvidson explains. "And our Mars research involves a huge question of sustainability ... We're trying to understand past climate, the role of life, the planet's evolution. ..."

This image of Mars was taken from the NASA Hubble Space Telescope on March 10, 1997.

Send rover right over
Roughly the size of golf carts, the non-polluting science utility vehicles are far more robust than the Pathfinder (and path-setting) rover that roamed Mars for three months in 1997. The 2004 twins are equipped to search out the history of Martian water and climate, covering as many as 300 feet a day. They have six wheels; solar panels; panoramic cameras; a robotic arm wielding a rock abrasion tool, three spectrometers, and an imaging microscope; plus a Mars-to-Earth antenna that sends and receives data and another that communicates with the orbiters; heaters; magnet arrays, and more.

At the end of each Martian day, or "sol," the rovers beam data to Earth and faster-transmitting orbiters such as the European Space Agency's Mars Express—for which Arvidson is a science team member. It is then sent via Internet for archive assembly to NASA's Planetary Data System Geosciences Node, which is part of the Earth and Planetary Remote Sensing Laboratory at Washington University—as the Geosciences Node director, Arvidson is responsible for the data archives.

"Besides doing terrific science, Ray is also the best in the world at creating the mission's legacy," says Squyres. "He will take this incredibly complicated mass of data and documentation and create an archive the scientific community will use for decades!"

Discoveries, puzzles, and firsts
Foremost among the rovers' discoveries is evidence Opportunity found of a persistently wet environment that could have been hospitable to life. (At the Spirit site, chemical, mineralogical, and textural evidence is building that ice or modest amounts of liquid water once was present on the planet's surface.)

Opportunity found the rock, dubbed "Bounce," near the rover's landing site, Meridiani Planum. Scientists use the rover's minitiature thermal emission spectrometer to take measurements.

Opportunity began to live up to its name the moment it landed in tiny Eagle Crater (an "interplanetary hole in one," as Squyres has said). Planetary geologist Bradley L. Jolliff, Washington University research associate professor and a MER science team member who has conducted extensive research on moon rocks, was elated about what happened next. "We turned on the cameras and saw this beautiful outcrop of rocks [exposed bedrock the size of a street curb on the crater's inner slope] right in front of us!

"The second delightful thing," Jolliff says, "was that instead of being (volcanic) basalt, so common on Mars, these were sedimentary rocks! Eventually, their chemistry and the mineralogy told us that they had to have been formed from some kind of shallow, standing body of water."

On NASA's Web site, Ed Weiler, associate space science administrator, commented, in part: "This dramatic confirmation of standing water in Mars' history ... gives us an impetus to expand our ambitious program of exploring Mars to learn whether microbes have ever lived there, and, ultimately, whether we can."

(Opportunity has since sent pictures of rock containing cross-layers, indicating its formation in flowing waterand that the robotic photographer probably was parked on the former coastline of a salty sea.)

The rovers' countless finds include intriguing puzzles. One example: First observed near Gusev, very strange soil became detached and folded like a rug on a floor when the lander's airbag scraped it. And one mission "first" was a suite of joint measurements between Spirit and the orbiting European Space Agency's Mars Express—and the first coordinated, detailed readings of an atmosphere column and surface features.

At the second frontier, intensity and free ice cream
The other frontier is in the Space Flights Operations Facility within JPL's sprawling complex in Southern California—where irrigation has coaxed patches of lush vegetation from native desert, scrub, and chaparral. Four floors belong to the hand-picked 50-member Science Operations Working Group (SOWG)—which Squyres and Arvidson chair—and the project's JPL engineers.

Professor Ray Arvidson spends a lot of time working with students and engaging them in science. At JPL (at right), he works with Bethany Ehlmann, A.B. '04, who is starting studies at Oxford University as a Rhodes Scholar in fall 2004.

Everywhere, sedimentologists, geologists, geochemists, atmospheric scientists, geophysicists, and students share a focused intensity. It shifts somewhat when they greet one another, grab a free ice-cream bar from a hallway freezer, or read a board where some wit has asked what music is best on Mars and answered "rock music." But essentially, their minds are on Mars—and in the control room, the operations room, the downlink room, the all-hands meeting room, where they are rewriting planetary history.

In addition to including outstanding Washington University colleagues (named in this article and accompanying sidebar at article's end) in the mission, says Squyres, "Ray brought an absolutely incredible bunch of graduate and undergraduate students. He always has this swarm of incredibly smart people buzzing around him! He brought that swarm with him, and they've done a fantastic job on the whole mission!"

One of those smart people is recent graduate Bethany Ehlmann, who received a Rhodes Scholarship and is beginning studies at Oxford in September, and is one of several such scholars Arvidson has mentored. "Bethany is so good that she has taken on three different roles in the mission," says Arvidson. She works with the soils and rock physical properties group, helps plan activities for the instrument arm, and often serves as the SOWG documentarian. In that demanding capacity, Ehlmann works all night with the chair and engineers on the rover's next-day activities to be sure the agreed-upon science observations are incorporated correctly.

"It's an incredible experience to be here working with leaders in the field!" says Ehlmann. "Ray has been such a tremendous, shaping influence on me during my time at Washington U."

Perched at the lip of Eagle Crater, Opportunity looks down into its former home. The rover's panoramic camera shows one octant of a larger image. The full panoramic image, dubbed "Lion King," was taken in eight segments using six filters per segment, for a total of 558 images and more than 75 megabytes of data.

Another star is fifth-year doctoral student Frank Seelos, who is writing his dissertation with Arvidson's oversight. Seelos designs scientific activities for the physical properties group, does spectroscopic analysis, and is a downlink lead on the Pancam team where he monitors the operation of the rovers' panoramic camera system. "Participating in this mission is an unbelievable opportunity," Seelos says. "And Ray has been a fantastic boss. He can be tough—but that's a good thing. He generates a constant flow of ideas."

The entire science team is relieved that the robots' human partners no longer live on Mars time. Because sols are 37 minutes longer than days, a workday that initially started at 8 a.m. (or in Arvidson's case, 6 or 7 a.m.) eventually begins at night. As the group became increasingly efficient at uplinking the next sol's operating sequences, Pacific Time was reinstated.

Until accumulating dust, diminishing sunlight, and cold temperatures on Mars shut down the rovers' power supply, the science team's intensity, anticipation, and exhilaration will continue. As Jolliff puts it: "I have to stop and pinch myself and say: 'This isn't the desert in Southern California or out on the range in Utah—this is Mars!'"

And sooner or later, Arvidson and his colleagues may indeed find signs of past life on the planet, perhaps with the help of NASA's Mars Reconnaissance Orbiter, slated to launch in March 2005, or Phoenix, a landed scientific laboratory that will explore Mars' higher latitudes in 2007. (Arvidson will be co-investigator on both.) But whether or not such evidence materializes, data gathered so far have worlds to tell about the kind of geochemical conditions that may have preceded life on Earth, where rapid, violent climate and tectonic change eradicated the clues.

All of which helps explain why, whenever Ray Arvidson is asked whether he anticipates a letdown when the MER robots finally shut down, he responds: "NO! No, not at all!"

Judy H. Watts is a free-lance writer based in Santa Barbara, California, and a former editor of this magazine.

Planetary Pathfinders
In addition to the Mars mission team members named in the article, the following people in the Department of Earth and Planetary Sciences are part of the pioneering group out West who have contributed mightily to the mission's success.
Edward A. Guinness, senior research scientist
Larry A. Haskin, professor
Gabby Izsak, mission archivist
Margo Mueller, assistant to Ray Arvidson
Susan Slavney, archive specialist
Nathan Snider, systems analyst
Tom Stein, computer systems manager
Alian Wang, senior research scientist
Jennifer Ward, graduate student
Note: Roger Phillips, professor and director of the McDonnell Center for the Space Sciences in Arts & Sciences, is working on the mission from St. Louis.