On the Road Again

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.’

    6 Responses to “On the Road Again”

  1. alex Says:
    October 21st, 2008 at 5:59 am

    Hi your article is quite good, here we can get some knowledge about mars. I really like it.

  2. Dusan Says:
    October 23rd, 2008 at 11:41 am

    Hello Ashley,

    I have watched the Mars Exploration Rovers project from the landing on Mars. It is incredible, the rovers are still alive. I can’t believe it’s almost five years. The project has been prepared really well.
    Good luck! Dusan.

  3. Mike Says:
    October 23rd, 2008 at 4:06 pm

    The rovers should be an inspiration to anyone trying to do something difficult. Theirs is an amazing story. Let’s hope we are looking forward to their sixth year of life at this time next year!

  4. David Roles Says:
    November 12th, 2008 at 8:24 am

    After seeing photo PIA10128 showing the huge buildup of dust on Spirit’s solar panels it would appear that Spirit could use a dust devil to clean them off (as has happened previously). However, since we can’t always depend on luck, has any thought been given to addressing this problem with regard to the next mission, the Mars Science Laboratory rover. I would think that if a can of compressed air with jets aimed at the solar panels were included on the rover, whenever a dust buildup accumulated, a command could be sent to blow them clean.

  5. DEAN GRAHAM Says:
    November 16th, 2008 at 7:11 pm

    Loved the Mars stuff since Viking, any reason why a wind turbine wasnt included for possible back up power generation? Good luck rovers

  6. Paul J. Says:
    January 26th, 2010 at 2:33 pm


    I appreciate your blogs. You do a good job humanizing what are intensely technical endeavors. I hope you can appreciate the value in that. The general populace is often intimidated by the overly technical aspects by which projects like those you’re involved with are generally discussed, and they feel isolated, unable to connect and feel like they’re a part. These people, however, are voters, who can influence the genesis or outcome of important projects. They are in essence “partners” who get very little attention and seem undervalued by project policy leaders. I applaud you in your effort to help bridge the gap and help those who may have an intense desire to connect, find a way to do so starting on a plane they can relate to; the human spirit. Thanks…

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