Ever since humans first ventured into space we’ve been enamored with gazing back at Earth, slowly revolutionizing our perceptions of our cosmic home across more than half a century of spaceflight.
One of the biggest advances for viewing our planet from space was the creation of the International Space Station (ISS), an orbital outpost 400 kilometers overhead that has been continuously crewed since November 2000. Another was the 2010 installation of the ISS’s multiwindowed “Cupola” module that is custom-built for Earth observations. But the greatest breakthrough of all may well be the spaceflight career of NASA astronaut Don Pettit, who has spent more than a year in orbit.
Pettit is not just an astronaut. He’s also an accomplished amateur photographer and gifted tinkerer. He compulsively snapped thousands upon thousands of pictures of Earth across two long-duration stints on the ISS in 2002 and 2011, and even used spare parts on the ISS to build new photographic equipment in his quest for the perfect shot. Through the lenses of Pettit’s cameras the Earth takes on an almost alien beauty. Infrared and monochrome images of the land and sea reveal otherwise-invisible weather patterns and plant growth. Cities at night glow like starry galaxies in short exposures; in long time-lapse images they smear out beneath pinwheeling stars, undulating aurorae and flashing thunderheads to wrap the spinning planet in neonlike bands of light.
The very best of Pettit’s out-of-this-world photography is now gathered into a single, awe-inspiring coffee table book: Spaceborne, published by Press Syndication Group. Along with thoughtful reflections from Pettit himself about the view from orbit, the book also features a forward by Alan Bean, a retired Apollo-era astronaut who walked on the moon. Pettit talked to Scientific American recently about the context and craft behind his gorgeous photographs.
[An edited transcript of the interview follows.]
Why have you spent so much time taking photographs in space?
Well, most astronauts take photographs up there. Why wouldn’t you? It’s a rare privilege to go. I look at space travel as kind of like how Arctic and Antarctic exploration was, circa 1910. You look at Shackleton and Scott, Byrd and Amundsen, and they were going places where most had no clue as to what it was really like, but all these explorers took pictures and shared the experience with as many people back home as were willing to look and to listen. That’s what we’re doing in space right now—going somewhere most people can’t and bringing back photographs and videos to tell the stories. Even if there is no replacement for simply being there, I feel a moral obligation to try to explain what it’s like and to share my experience with the people who really made it possible—the taxpayers who support NASA and projects like the International Space Station. Without everybody on Planet Earth, I wouldn’t be able to go off-planet.
How did you start?
I pioneered some of the techniques for taking sharp photography of cities at night and other nighttime phenomena in 2002 and 2003, when I was on my first spaceflight as part of Expedition 6 to the space station. Our mission could’ve been as short as two and a half months, but it was extended to almost six months after STS 107 [the shuttle mission that resulted in the loss of the Columbia orbiter and its crew as well as the ultimate retirement of the space shuttles—Editor]. Having more time on station allowed my skills as an orbital photographer to blossom.
What were some of the skills and techniques you needed to develop?
Our atmosphere buffers light, so when you’re exoatmospheric there’s a very stark contrast between sunlight and darkness that autoexposure mechanisms on cameras aren’t designed to handle. To get the total dynamic range, one thing I’d do a lot was to manually shoot five exposures in rapid succession, each one f-stop apart, then combine those later on the ground. And you don’t have much room to improve composition—you can’t move five or six steps to the right to frame a shot better. You can only take pictures where the engineers decided to put windows.
Another thing to think about is orbital motion. The station orbits the Earth about every 90 minutes, which means it moves so fast that to take a sharp picture of something on the surface you have to track it—even in daytime and at the fastest shutter speeds. I needed one-second exposures for some of my nighttime photography, and you just can’t handhold and track for that long and still get a sharp picture. I used spare parts from around the station to put together a barn-door tracker, which is something amateur astronomers use to cancel out Earth’s rotation to take long exposures of stars. It’s just a platform with a telescope and camera mounted on it; you look through the telescope, manually tilt the platform by rotating a threaded bolt, and take pictures with a cable release. We were using film back then, but nowadays the cameras are better and all-digital, so the barn-door tracker isn’t needed anymore. It got torched years ago—a deorbital cremation on a Progress or an HTV [automated cargo spacecraft] reentering Earth’s atmosphere.
Which of your photographs are you most proud of?
Probably the pictures of Earth at night. The star trails and the city lights really sing to me. There’s a lot of phenomenology in the star trail pictures, because they represent collective 30-minute exposures. Stuff shows up that you can’t see in just one.
Atmospheric airglow, and red and green aurorae from atomic oxygen. Flares of sunlight bouncing off distant communications satellites, and flashes of lightning from thunderstorms. And at night you can see these strange neon colors from cities and other places on the ground. The oranges come from sodium vapor lamps—that’s most of what we have in the U.S. The blue-greens come from mercury lamps and are more common in Asian cities. Other colors can come from things like LED billboards or high-intensity xenon lights on deep-sea oil platforms and fishing boats. Older cities look completely organic, the equivalent of cattle trails becoming roads and then illuminated superhighways. There’s nothing organic about younger cities—they follow north-south/east-west grids, laid out by some master engineer.
It seems ironic that those same city lights you love photographing from orbit are keeping people on the ground from seeing the stars or watching a space station pass overhead. What do you think that says about us?
At night, each city is a beacon of humanity, projecting something into space that says something about us—all the way from opulence and light pollution and needlessly consuming energy to the simple desire of human beings to push back the night and pack more activity into times that we’d normally be dormant or throttling down. Electric lighting basically allows us to extend our lifetimes. I think that’s why we’re willing to put up with all the light pollution and the loss of the nighttime sky.
You’ve probably spent more time than almost anyone else looking at the planet from orbit. Besides nighttime city lights, what other beacons of humanity did you see up there?
Looking at the Earth from space reaffirms your preexisting ideas and beliefs. If you think human beings are a plague upon the planet and you see Earth from space, it will reaffirm your view. I worry about being labeled a heretic when I say this, but when I look at the Earth from space, particularly daytime Earth, with my eyeballs, I can barely tell that humans are there at all beyond some logging and irrigation circles. If we are talking about just a human being, floating in the space station’s Cupola and looking at Earth in daylight, you’d be hard-pressed to see much. You fly over Los Angeles and it just looks like a gray smudge—it could be human activity, or some volcanic ash flow. Of course if you look with binoculars or a telephoto lens, it’s a totally different story.
What’s heretical about that?
It’s politically incorrect, because everyone says we’re trashing the planet, and in some ways we are. To me the epiphany is that Earth is perfectly happy going on with or without us. It’s a different twist, to say that we don’t so much need to take care of the Earth as much as we need to do things that allow us to survive on Earth. I really feel we are wedded to this planet, until extinction we do part. We’re not stewards of Earth; Earth is steward of us. It’s up to us to figure out how to live on this planet without destroying the essentials for us to stay alive.
Now that you’re back on Earth, do you still take photographs? And do you think you’ll ever get the chance for more orbital photography?
I take thousands of pictures every month in spite of not being in orbit. I do wide-field, time-lapse astrophotography. I go out in my garden with a macro lens and take pictures of insects and flowers in my garden. Some are pictures documenting the family, the kids or my dog, but a lot are just artful renditions of things I find fascinating and beautiful as features on the surface of this world we call Earth.
I’m optimistic about going back to the space station, because I’m still an active NASA astronaut and in the pool for flight assignments. I keep myself trained up and in good shape, and I have skills and experience you need on orbit. NASA likes to have a mix of rookies and veterans on station, so there is a small, finite flow of experienced astronauts that get reassigned. I’ve got a whole smorgasbord of things that I still want to do with photography that have yet to be done from space, so I am hoping I get to fly again. I’d love to fly again. But you never know whether you’re going to get another chance until it happens.