In human years, Spirit and Opportunity are baby boomers — in their 50s and 60s. In dog years, they are over 350 years old! The rovers “keep on keeping on” despite having to drag squeaky wheels, losing full range of motion in stiff arms, and needing to reboot the ol’ computer brains every now and then to cure memory problems.
“I’m an old boomer at 58-years-old, and I’ve had to walk with a cane for arthritic problems in the past,” says Engineering Team Chief Jake Matijevic. The rovers have similar “arthritic” problems in their joints. The motor in Spirit’s front right wheel no longer works. Opportunity’s stuck heater circuit causes shoulder and elevation joints in its robotic arm to experience temperature cycles from -94°F to +158°F (-70°C to +70°C), resulting in wear and tear.
Yet, like most boomers, the rovers are young at heart. Their longevity and success continue to set high expectations for future generations of robots–and even human explorers–who will brave extreme conditions on Mars.
Keeping Warm and Flexible
Bundled in protective thermal blankets designed for the red planet’s harsh climate, the rovers experience daily surface temperature changes of 150°F (66°C). Those extremes will make it difficult for future humans to dress appropriately for their adventures on Mars. Luckily, doctors are already looking into what humans would need to wear to survive on Mars.
Dr. Jeff Jones, a NASA Flight Surgeon from Johnson Space Center in Houston, has lived in simulated martian conditions in the Arctic for NASA’s Haughton-Mars Project, which uses the polar desert as a testing ground for future human exploration on Mars.
Jones has tested spacesuits that will protect planetary explorers from extreme temperature cycles and cancer-causing radiation that passes through the thin martian atmosphere. This past summer, Jones and the Haughton-Mars Project team donned “concept” space suits for real science experiments in the martian-like environment.
The adventurer scientists discovered suits made for Mars must be more flexible than current suits used to build the International Space Station. “Astronauts on Mars will need to be able to bend down to collect rock samples . . . and stand back up without falling,” laughs Jones.
Opportunity can relate. The rover is feeling the pain of constrictive joints and is at the brink of losing the ability to bend its arm down and reach rocks on the surface. From afar, diehard engineers are working around the rovers’ aging problems, taking preventative measures and proper care of parts that have long passed their original three-month warranties.
“Mindful of the risk of losing the motor on the shoulder joint entirely, we came up with a plan that allows us to drive occasionally with the arm ‘unstowed.’ With care, the vehicle can move with the arm kind of dangling out there in the breeze,” explains Matijevic. “I can’t remember anyone ever saying, ‘This is hopeless.'”
Astronauts and rovers are far out of doctors’ and engineers’ reach, so the best way to solve a medical or mechanical problem is to prevent it from happening. Jones prescribes old-fashioned exercise to keep bodies working. “Astronauts on the International Space Station exercise for two hours a day to keep their heart and muscles strong,” says Jones.
Mother Nature on Earth also provides anti-aging, body-cleansing agents. “I encourage everyone to eat things they don’t like — like broccoli and Brussels sprouts — to keep your body healthy with antioxidants that sweep away toxic particles in your system,” says Jones. “A challenge for astronauts is that we don’t yet have a dedicated spaceship refrigerator that will keep fruits fresh, so we’re developing antioxidant supplement formulas they can take to stay healthy on their way to Mars,” says Jones.
Mother Nature on Mars has a different system-cleansing solution for rovers. Turns out, the martian breeze has been helping the rovers age gracefully by sweeping dust off the energy-producing solar cells. Both vehicles have benefited from dust storms that have acted like heart and lung surgeries on humans, unclogging vital organs. “The dust storm cleaning events have revitalized the rovers,” says Matijevic.
Setting Expectations for Future Generations
That’s important, because the rovers depend on sun intake for their health. Like many boomers, they will be seeking the sunniest places to face winter, which is once again approaching on Mars. Having already lasted over a martian year – almost nine times longer than planned! – no one is sure just how much longer they will last.
“Once the rovers stop working, I’ll miss seeing new pictures every day, but since I don’t consider myself ancient, I hope to work on the Mars Science Laboratory mission after the rovers die,” smiles Matijevic.
And, as new generations of rovers continue driving faster and farther on Mars, future generations of astronauts–perhaps the grandchildren of today’s Baby Boomers–will begin to head farther away from Earth. On the horizon is a whole new era for a human-robotic partnership, with the young-at-heart rovers raising the bar for all who follow.