Author Archive

Growing Up With the Mars Rovers

Tuesday, January 20th, 2009
Ashley Stroupe
by Ashley Stroupe
Robotics Engineer

I am not supposed to be here, working with the Mars Exploration Rovers. There wasn’t supposed to be a Mars Rover here for me to work on. I arrived at JPL less than a month before Spirit’s landing in January 2004. Long before I earned the privilege of working on such a project, the three-month mission (six if we were lucky) would be completed. Robots are intricate machines, and Mars is a harsh place. Neither Spirit nor Opportunity should be here - and, as a result, neither should I be here to talk about them. Five years on Mars - inconceivable! But somehow, Spirit, Opportunity and I are celebrating our fifth anniversaries within a few weeks of each other. We’ve grown up together, in a way.

I have been working with the rovers for almost four and a half of their five years. I’ve discovered that Spirit and Opportunity are more than just a couple of robots or tools - they are a grand vision, a shared dream. A dream so powerful and so compelling that even those who come late to it, as I did, are fully invested. I look around at the room as I write this and I see people who have been here from the beginning (or even before the beginning from Pathfinder days in 1997) and I see the newest generations - those I have helped to train and with whom I have shared the vision. This dream is large enough for all of us.

This is a partial view of a spectacular image from Spirit atop “Husband Hill.” The rover tracks were my “first” on Mars.
Full image

Most engineers build a product and give it to the user. But those of us working on the Mars program are lucky enough to continue working with the scientists and get a real sense of the great purpose of what we do. We are an integral part of contributing to our understanding of the universe around us. I often step back and realize how truly fortunate I am, working on this amazing project with these remarkable, talented people.

This team of people is a family, and the rovers are our children. And, like parents of adult children who have moved away, we worry, we try to keep them safe, we try to teach them what we know and we give them guidance. Sometimes they listen and sometimes they don’t. But together, we’ve made amazing discoveries. Once Mars was a warmer place, a wetter place, a more Earthlike place - something we could only infer indirectly before. And it’s still a beautiful place with strangely colored sunsets that remind us we’re looking at another world.

Now, experience has matured us. And aged us. We have faced a lot of challenges. Racing to find places to survive harsh Martian winters, climbing mountains and crater walls, riding out dust storms, and working around arthritic body parts (broken wheels and failing arm joints). There have been sleepless nights and new gray hairs. But as Spirit and Opportunity begin long journeys to new places, we remember our starry-eyed youth and still nothing seems entirely out of reach. Five years on Mars? That’s just the beginning.

On the Road Again

Monday, October 6th, 2008
by Ashley Stroupe
Robotics Engineer

The Mars Exploration Rovers, Spirit and Opportunity, have been exploring the geology of Mars for nearly five years - well beyond their expected lifetime of three to six months. In that time they have made amazing discoveries, most importantly finding proof that Mars was once a much wetter planet that may have been capable of supporting life. Spirit has been exploring a region around a small mountain range that seems to have once had hot water or steam, the very kind of place life might have originated on Earth. Opportunity has been investigating craters in the plains that provide views deep underground and show evidence of flowing water in the ancient past.

I am a roboticist at JPL, and just one member of the large team of people who work together to enable Spirit and Opportunity to explore. My work focuses on getting robots to do things intelligently, both by developing software for robot autonomy and by operating our two spacecraft on the surface of Mars.

Spirit and Opportunity have become like old friends to the operations team. Every day we are anxious to hear the latest news and see the snapshots taken from the new places they are visiting. Working with the rovers never gets routine as each new location brings new circumstances and new problems to solve.

The white-capped Von Braun hill in the distance is Spirit’s next destination.

The challenges of operating Spirit and Opportunity have continued to grow and change as they age, and we have had to develop new ways of driving and operating the robotic arm as capabilities decrease. We are discovering how to operate these rovers in ways for which they were never designed. The discovery process requires a lot of imagination and a lot of practice, both on Earth with our engineering rover and on Mars. It’s this kind of completely new and unanticipated problem that is the most fun for engineers like myself to solve.

Both rovers are now starting to show their old age of 4¾ years (that’s at least 300 in rover-years!), and some parts do not function quite as well as they used to. Spirit has to drive more slowly and constantly monitor her progress to make sure she is staying on the right path to compensate for a broken right front wheel that tends to dig into the soil. Opportunity has limited reach with her instrument arm due to a failed shoulder joint, and has to approach science targets in a very precise way. Despite these limitations, both rovers are now about to embark on difficult journeys which will require them to set new milestones and we will need to learn new ways of driving yet again.

After surviving a very difficult winter, Spirit is soon going to be heading south toward some interesting geological features: a hill called von Braun and a depression called Goddard. Scientists hope investigating these unique features will provide insights into the Martian past. They are looking for additional evidence of hot springs or steam vents that have been hinted at by other observations in this region. Based on comparisons to similar locations on Earth (like deep sea vents), this could be an ideal place for life. Reaching these exciting features requires a long drive through sandy terrain in a very short period of time before next winter arrives. This will mean pushing Spirit to new levels of performance.

Opportunity is getting ready to head for “Endeavour” crater, having finished up its study of “Victoria.”

Opportunity is finishing up her observations of the 800-meter Victoria crater and then will begin a 12-kilometer, two-year odyssey toward a huge crater (about 22 kilometers across) to the southeast. As this means more than doubling the total distance Opportunity has driven in her lifetime, we are excited to be developing new methods to make record distance drives safely. This will require relying on the rover’s onboard autonomy to keep her safe more than ever before as we drive each day well past what we can see.

Spirit and Opportunity’s story of continued exploration - boldly striking out after one new goal after another, far beyond their design lifetimes - is a genuinely inspiring one. It’s as if Magellan circumnavigated the Earth, then paused and said, ‘You know, that’s not good enough. Let’s go to the moon, too.’