Life on Mars
Mars rovers Spirit and Opportunity were only meant to last 90 days, but they kept going and going and going, gaining friends all along the way.
Janet Vertesi. Seeing Like a Rover: How Robots, Teams, and Images Craft Knowledge of Mars. University of Chicago Press, 2015. 304 pp. $35.
She’s alone out here. She’s a scientist, a spy, an explorer. She wasn’t meant to live this long—long enough for the government that sent her to want to get rid of her, to cut her off and leave her to die. Sure, she’s had a rough go of it: she’s not in the best shape; she’s had to tackle circumstances she wasn’t prepared for. But she’s still sending back good intel. Her team is counting on her, pulling for her, giving her advice on where to go. None of them know how long she’ll last; the sniper could strike at any time. She’s the Mars rover Spirit.
Launched in 2003, Spirit and its twin, Opportunity, were sent to Mars to find evidence of past water on the planet’s dry, red surface. Each was designed to last for 90 days and to use its spectroscopy equipment, rock-scraping tool, and nine cameras to send information back to its human teammates on Earth. The funny thing was, no one told the rovers they only had 90 days. Spirit drove around for over five years until it got stuck in soft soil in 2009 and couldn’t survive the Martian winter, while Opportunity is still going more than 13 years after its arrival.
For more than a year Janet Vertesi, a Princeton University sociologist, sat in with Spirit and Opportunity’s earthbound teammates as they decided where to send the rovers, which photographs and measurements to take, and how to calibrate and interpret the resulting images. In Seeing Like a Rover: How Robots, Teams, and Images Craft Knowledge of Mars, Vertesi shares her behind-the-scenes experiences. And while there is plenty of drama, the book is an ethnographic work at heart, with its focus on the humans and the culture and customs they created around the two robots and their research.
As we learn in the book, more than 150 people spread across four countries make up the Mars Exploration Rover team, which includes graduate students, professors, civil servants, and hardware developers. Generally, team members fall into one of two categories: scientist or engineer. The scientists—geologists, chemists, physicists, biologists, and astronomers—interpret the evidence the rovers send back. The engineers are responsible for the rovers themselves, from the circuits and wheels to the communications systems and cameras.
Both groups need certain information from the rovers on any given day, but the number of bytes, hours, and watts available are finite. The result is a constant balancing act, one that’s worked out in the team’s daily meetings. The Science and Operations Working Group decides what the rovers will do the next day, minute by minute, walking the line between operational concerns (conserving power, not causing damage) and “squeezing out as much science as possible.” The Long-Term Planning Group looks further ahead, making sure the rovers keep to the strategic plan for as long as they remain active.
The thing is, as Vertesi reports, no one quite knows how long the rovers are going to remain active. The threat of rover death is constant and is referred to by the rover team as “the sniper” (as in “the sniper could strike at any time”). Then there’s the threat of “political death”: budget cuts, accusations of worthlessness, an order from on high to abandon the rovers and move on to other projects. The team members frequently exhort each other to “give the taxpayers their money’s worth on this sol” (the name for the 24.7-hour Martian day).
The project is a high-stress pressure cooker, and so it is important that each team member remains invested. As one team member explains, “At the end of the meeting you want people to have a sense of ownership of the plan. . . . It’s the whole empowerment thing, the team needs to feel like they’re part of the process, and they’re getting their two cents in and we’re doing the right thing.” Rather than calling the rover “she” (which generally only occurs when the team is speaking of the rovers’ past actions or current physical status), it’s “we”: “We’re at Cape Faraday,” or “We’ve got some tough terrain up ahead.”
It’s not only an emotional investment; it’s a physical one as well. For the first 90 days the team lived on Martian time, operating on sols rather than days. The engineers that plan where the rovers will photograph contort themselves into the shape of a rover, using their hands as surrogates for the cameras, trying to see with their bodies how to program a rover almost 40 million miles away. They scoot around in their chairs to mimic a rover’s path. They get so used to associating their own bodies with the rovers’ that when one scientist suddenly found she couldn’t move her right wrist while gardening, she wasn’t surprised to learn at work the next day that Spirit’s right front wheel was stuck. An engineer had shoulder surgery just when Opportunity’s instrument arm started having problems, and he broke his toe when Spirit’s wheel broke.
They chuckle about these occurrences, but the engineers and scientists clearly enjoy this physical connection with the rovers, even if they haven’t been able to touch them since they left Earth. Now they only have pictures from the rovers’ cameras. I say “only,” but those pictures are everything. Pictures are maps, showing the engineers where to drive. Pictures are magnifying glasses, allowing scientists to get a close-up look at something millions of miles away. Pictures are public-relations tools, awing audiences and drumming up support. Pictures are deciding factors in times of conflict, letting the evidence speak for itself. Pictures are the guidebook to a place we’ve never been. Those cameras are the team’s eyes on Mars, enabling them to see like a rover.
There are two types of cameras on board the rovers that match the two types of people on the team: engineering cameras and scientific cameras. The engineering cameras help with driving: monochrome, low-resolution navigation cameras (Navcams) over the wheels, and black-and-white hazard avoidance cameras (Hazcams) mounted on the front and back. The scientific cameras are the microscopic imagers on the rovers’ robotic arms that can take extreme close-ups of rocks and soils, and the stereo, full-color panoramic camera (Pancam).
The Pancam can send back gorgeous panoramas worthy of a coffee-table book, pictures that frequently come in handy for impressing the public and selling the importance of these missions to their funders. But the Pancam can do much more than take a pretty picture. Different combinations of the camera’s 13 filters reveal aspects of the landscape. Using its two stereoscopic lenses, three-dimensional images can be created that help us better understand the surface texture or help the engineers get a clearer idea of the size and scope of a particular feature. False-color images bring out features that might otherwise be invisible. Color levels from the photos are turned into graphs to better see the distribution of different types of soil. The images don’t just aid in interpreting the findings of other rover tools; they are tools themselves.
All the images are made available to the public immediately. The rover mission’s principal investigator frequently says that “people should be able to get up in the morning, get their coffee, log on to the Internet, and see what’s happening on Mars today.” And so they do: an online community of unmanned-spaceflight aficionados check the pictures every day, discuss the rovers’ movements, and make their own algorithms to create true-color images of Mars. Rover team members, for their part, read the aficionados’ postings to see how their findings are interpreted. The connection is not just scientific; for the rovers’ second birthday enthusiasts sent a birthday card as well as an “I am 2!” button for the lab’s model rover. The result is a community built on science and emotion, even if most of that interaction is never done face-to-face. It’s surprisingly easy to fall in love with these little rovers, if only through their pictures.
Spirit had birthdays after her second, but the hazards of the Martian landscape eventually doomed her. She fell through a layer of normal-looking ground into a soft bed of soil on May 1, 2009. Though the team tried for nine months to get her out, NASA eventually decided to make her a “stationary research platform” and stopped trying to move her. The team tried to orient her solar panels to keep her charged through the Martian winter, but it is likely her batteries lost too much energy. She was last heard from on March 22, 2010.
Vertesi, who by this time was no longer a part of the rover team, was invited back for the funeral. Team members spoke fondly of their spirited little robot, who was built for flat terrain but tackled hills the size of the Statue of Liberty; who didn’t give up on finding evidence of water even though her sister, Opportunity, had much better luck; who had a busted wheel and limped along but never stopped.
“If you can listen to that whole story and you can look me in the eye and say she doesn’t have a personality,” said one team member, “then you are the robot!”