"We have an unknown distance yet to run; an unknown river yet to explore. What falls there are, we know not; what rocks beset the channel, we know not. Ah, well! We may conjecture many things... With some eagerness, and some anxiety, and some misgiving, we enter the canyon below, and are carried along by the swift water."
—John Wesley Powell
The Exploration of the Colorado River and Its Canyons (1875)

John Wesley Powell and his motley crew of men who set out to explore the Colorado River in 1869 admitted that they had no idea what was coming. And yet, they walked, and waded, into the adventure knowing full well that they may not return–indeed, some of them didn't. As I think back on the last decade's adventure of designing, building, testing, launching, and operating on Mars two complex and hardy robotic space vehicles called Spirit and Opportunity, I can't help but wonder if we were just as naive when we started out. None of us thought we might be risking our lives, of course, but we certainly ended up risking our health, our marriages and family relationships, our friendships, our scientific careers on some level, and sometimes, it seemed, our sanity.

Our missions were not the first to land on Mars, to rove on Mars, or to acquire images of the ruddy alien landscape. The two Viking landers (1976–1982, 1976–1980) and the Mars Pathfinder lander and its Sojourner microrover (1997) came before us and were phenomenal technical and scientific successes. Those missions beamed back tens of thousands of images that revealed the surface of Mars, for the first time, to be a rocky, dusty, and strangely familiar place. Our achievements with Spirit and Opportunity were only possible, to paraphrase Isaac Newton, because we were already propped up on the shoulders of these first giant missions of Mars exploration. We have not been the first to see the surface of Mars, but we have had the privilege of being the first to see the places we have visited in an entirely different, and ultimately more human, way.

The difference between the views of Mars from the Vikings and Pathfinder and the views from Spirit and Opportunity is the difference between “acquiring images” and “taking photographs.” Acquiring images is a technical, science-driven, resource-limited activity. Every space mission to a new place—whether human or robotic—has to carry a camera. These cameras are the eyes that have to tell the stories of new alien worlds to the people back home who couldn't go. They also have to be able to gather the required information about a place—size, shape, distance, number of rocks in the way, etc.—to allow scientists and engineers to run the mission and to make discoveries. But it's not easy to take these pictures or to send them home. Spacecraft and instruments are complex, sometimes finicky things to operate, and the time to take pictures is often a scarce commodity. Even more scarce, usually, is the bandwidth necessary to transmit good quality pictures back home from outer space. It's like drinking from a fire hydrant with a straw. After a while, you'll quench your thirst, but only after wasting a lot of water.

Those of us taking photographs with the Mars rovers, on the other hand, have had the luxury of much more time devoted to picture taking, much more bandwidth for sending pictures back to Earth, and better resolution of our cameras compared with that of any previous Mars missions. These advantages have allowed us to not just acquire images, but to take photographs.

We can be photographers—artists—while at the same time gather all of the required scientific and engineering information needed to run the missions. When I am designing a camera sequence for the Pancams—panoramic cameras—for example, I can think about the same kinds of issues that landscape photographers consider in their quest to capture the spirit and stories of the land. How can we frame this particular shot? Can we include some foreground rover parts in the image to give the view a sense of depth? What is the balance of sky and ground? Do we view the scene in natural light or with enhancing filters? And how do we interpret the view later, in the computer "darkroom" where we process the images?

I was into landscape photography when I was a kid. My parents bought me a Pentax 35 mm SLR camera, and I spent a lot of time shooting the outdoors with my friends in the high school Photography Club. I was fascinated with the interplay of light and shadow in the environment, with the way a photograph could be framed and composed, like a musical piece, to tell a story to the viewer in a certain way. I went to the library and soaked up Marcel Minnaert's book The Nature of Light and Colour in the Open Air and checked out picture books about nineteenth-century landscape photographers like Timothy O'Sullivan and William Henry Jackson, and twentieth-century ones like Edward Weston and the master Ansel Adams. When I figured out how to hook up my camera to my telescope, I was hooked. Space was the ultimate landscape. That's when I knew that I wanted to get into astronomy and space exploration.

Little did I realize back then, though, that I'd have the opportunity to take some of the most spectacular photographs of martian landscapes ever made. In a sense, the pictures in this book represent the culmination of the dreams of a little kid who started fumbling with filters and f-stops in rural Rhode Island thirty years ago. I look at where it led, and I'm in hog heaven. I was trained as a scientist, but I've come back to my roots in many ways and have become a space landscape photographer. Indeed, all of us involved with the rover cameras have become photographers. Even the rovers themselves are photographers, in a way. We're the first photographers on the red planet.

—Jim Bell

Reprinted from Postcards from Mars by Jim Bell by permission of Dutton, a member of Penguin Group (USA) Inc. Copyright � 2006 by Jim Bell. All rights reserved. This excerpt, or any parts thereof, may not be reproduced without permission.