The Mars Rovers Are Pretty Good Photographers

A chat with geologist John Grant, curator of a new space photo exhibition at the Smithsonian.

Images: NASA/JPL-Caltech/Cornell University

From crisp sand dunes to bleak sunsets, photos from Mars are always awesome. Now you can see them all at the Smithsonian Air and Space Museum, which recently opened an exhibition called Space and Opportunity: 10 Years Roving Across Mars.

The show highlights the best photos taken by twin rovers on the red planet, Spirit and Opportunity—notice the aluminum tire track marks of an unmanned rover, slowly treading across the planet. With shots of dust clouds, craters and meteorites, the exhibit’s a celebration of a decade’s worth of photos and an incredible development in space engineering, which is still ongoing.

What’s incredible is that Spirit and Opportunity, which were launched to Mars in 2003, were given 90 days to expire and a goal of driving 1 km. But Spirit turned over 7 km before ceasing communication in 2010 while Opportunity traveled over 38 km, checking out everything from cool sunsets to meteorites and sedimentary rocks. Combined, the rovers have taken over 300,000 shots of Mars.

They each have nine “eyes” (or cameras), including four Hazard Avoidance Cameras on the front and back, two Navigation Cameras mounted on the neck and head, two black-and-white Panoramic Cameras and one monochromatic Science Microscopic Imager, mounted on the robotic arm which takes close up of rocks and soil. Last month, the cameras uncovered a new mystery rock on the planet.

With hundreds of thousands of images collected, how do you choose which ones to include in a space art show? I was curious, so I talked with the exhibition’s curator John Grant, a geologist in the museum’s Center for Earth and Planetary Studies.

Motherboard: The photos are incredible, have they ever been shown before?

John Grant: Some have been, all have been released. They show a selection from the hundreds of thousands of photos taken by two rovers collected over past 10 years. The few in the exhibition are the clear favorites.

How were they selected?

I pulled the science team, the engineers and the scientists, to send their best choices, and then edited it down to about 50 photos. The ultimate 50 were chosen by their aesthetics, stuff that is stunning and beautiful, but also related to the story to the rover missions. They’re intriguing images that teach about the mission and Mars.

You’re a geologist. The rovers were built to be robotic geologists. How?

The instruments on board include things like a microscopic imager, cameras, and spectrometers that tell us something us about composition. I imagine it’s like someone is picking up rocks and analyzing them. But the actual rover does not pick them up. We identify rocks we think are interesting. Opportunity’s arm is the length of a human arm, we can get real close and examine them in detail.

What was the best part of the cameras used, from the Pancam to the navigational cameras, hazard avoidance cameras and the Microscopic Imager?

The PanCam has 13 filers, while the hazard avoidance cameras allow us to see various viewpoints, scales, and resolutions but also identifying the rocks we want to look at.

The photos include images of dunes, dust clouds, and meteorites. What are your favorites?

My favorites keep changing, but right now they include a backward look at the track of the Opportunity rover, it’s a very desolate view with the horizon of the sky. I grew up on Lake Champlain and it’s very reminiscent of being on a boat on that lake. Another shot, from Spirit, is a sunset view of Husband Hill, named after the astronaut who died in the Columbia shuttle. It’s familiar to a sunset on earth.

They’re like a Postcard from Mars.

Jim Bell actually published a book called that. To me, what’s so stunning is they are so beautiful while telling the story of scientific discovery. We didn’t pick these pictures just because they’re pretty, they become a story for the viewer. We bring the ones that focus that the science team chose.

What are the videos in the exhibition?

There is an animation of the landing created before the actual landing. It shows how the rovers landed, which involves parachutes and airbags. Curiosity (the latest Mars rover) landed in 2012, but it landed differently. Opportunity is taken from each drive in Endeavour Crater. It’s a video that’s intriguing. Another video is from Spirit, from the first few years.

Why are the blueberries (the spherules) so important to include?

A lot of people have heard about them and to the science team, they’re important. In the exhibit, there is a ‘berry bowl’ showing the spherules. They are concretions founded by groundwater on Mars.

How long do you think Opportunity will last up there?

I get asked that question a lot. It’s almost impossible to answer. Ten years past its expiration, it is making stunning discoveries, still.

Is Curiosity up there, too?

I am involved in Curiosity mission; I am going to a Curiosity meeting in 10 minutes, maybe we’ll do another exhibit on that. Here we have two rovers supposed to last 90 days with a goal of going 1 km. Opportunity has driven more than 38 km. In terms of the scientific and engineering feat, it’s astounding. That was the basis of having the exhibit, being involved in the mission.

What is your role in the mission?

On Spirit and Opportunity, I’m the Science Operations Working Group Chair on the days I am assigned to work. I help decide what the rover is going to do that day. I have been doing that for 10 years. I don’t do it every day, but I did it a day last week. After 10 years it has become a part of my life. My wife and my child hear about it all the time.

What’s it like deciding what to do with the rovers?

It’s like herding cats—what to focus on with all these scientists with ideas? (Laughs). No, actually, we pre-trim our own expectation, but the process of deciding what to do is oiled, we’re used to it because people understand the rover and know how to make things fit within its capabilities.

The Space and Opportunity: 10 Years Roving Across Mars exhibition runs at the Smithsonian Air and Space Museum until September 14, 2014.