This year, NASA’s scientific rover Opportunity celebrated a milestone. It has been exploring Mars for ten years, even though it was only supposed to operate for three months.
John Callas is the project manager for Opportunity at the Jet Propulsion Laboratory in La Canada-Flintridge and has has been with the rover since the beginning in 2000.
“At that time scientists thought Martian dust would collect on the rover’s solar panels, block the sunlight needed to keep Opportunity alive and, essentially, starve it to death,” Callas said. The rover was originally designed to travel “about a kilometer on the surface of Mars, but has gone nearly 40 times further,” all while sending important scientific data back to JPL scientists.
“I mean this is really remarkable,” Callas added. “As it turns out, wind, periodically, will blow dust off the [solar] arrays. Power levels will go back up and that would give the rover a new lease on life – allowing it to survive the cold, dark, Martian winters.”
This sounds like a science fiction story, but it’s the reason why Opportunity has survived so long. To figure out how long the rover would last, the robotic joints that allow it to move around were tested over and over in a laboratory until they broke down. But, the joints have lasted much longer than even the tests that happened on the ground.
“We’re well beyond what these things were ever designed and ever tested to, so who knows how long they’ll last,” Callas said.
NASA and JPL have had a lot of practice exploring Mars, from their first rover, Pathfinder, to their fourth and current one, Curiosity. Each rover has given scientists a chance to learn how far they can push the limits of engineering.
“It all adds up to these really amazing killer missions where they do all of these new and complicated and scary things, and also build these really incredible, long lasting machines,” said LA Times science writer Amina Khan, who follows Mars rover missions closely.
But, becoming a leader in Mars exploration came with it’s challenges. Mars rotates at a different speed than Earth, making a Martian day forty minutes longer. So, scientists had trouble keeping a 9 to 5 schedule as Opportunity kept exceeding its life expectancy. For many scientists, working on Mars time was like being permanently jet lagged, your body can’t tell what time zone you’re in. “So, you are working in the middle of the night and you’re trying to sleep during the day when the landscaper’s outside with the leaf blower, cleaning your driveway,” Callas said.
JPL ended up modifying their whole rover schedule, splitting duties with researchers in other countries by sharing data online. This has become the model JPL uses with long-lasting Mars missions.
But, the discoveries made by Opportunity go far beyond wind and engineering. Opportunity has actually changed our relationship with the planet, according to Khan. Not only did the rover complete its primary mission of finding evidence of water, but it’s also been finding signs of water that we can potentially drink.
“Mars is one of those planets that could’ve been a lot like Earth pretty early in it’s history,” Khan said. “It’s kind of like a sibling that went down a different path and we kind of want to understand why that happened.”
Searching for drinkable water is key to NASA’s future goals of answering the questions: how did life begin on our planet and could it be sustained on another?
Joy Crisp, who is a planetary geologist at JPL, says the evidence of past life on a planet like Mars is locked in its ancient soil, a place Opportunity has been sifting through for years. The spry little rover has been drilling into rock formations to collect valuable data on what kind of water actually dotted the surface of the red planet.
“Reading the record in the rocks on Mars,” Crisp said, “we are getting at the question of, ‘did life ever get started anywhere else?’”
That sounds like a logical next step, because answering the question: “Are we alone?” is one of the great reasons why we explore other planets. Our dusty neighbor is still a good place to continue the search because humans have had a continuous presence on the surface of Mars, through these vehicles, since 2004.
So, what are we gearing up for next? “Looking to Mars 2020, the really big thing is to be smart about collecting some samples for potential return to Earth,” Crisp said. Bringing a sample back to Earth is a goal JPL is already figuring out how to accomplish, including how to receive a sample safely.
Searching for conclusive evidence that life once existed on Mars is exactly the kind of discovery that helps us understand our place in the Cosmos, and these rovers, John Callas said, are just the beginning.
“One could argue that this just the first decade of sustained human awareness and cognizance on the surface of Mars going forward,” Callas said.