As the planet-wide Martian dust storm clears, NASA scientists have increased their efforts to contact the nearly 15-year-old Opportunity rover, which has been silent since June 10.
Some scientists are beginning to feel apprehensive, but there’s a plan in place. The deep-space network of NASA communications satellites began a 45-day period of “active listening” on Wednesday, during which they will send signals from Earth to Mars several times a day. Radio receivers will listen passively and continue doing so until January 2019, at the earliest.
“I think we have a plan that, if the vehicle is alive, we’ll hear from it,” Steve Squyres, principal investigator of the Mars Exploration Rovers Spirit and Opportunity, told Gizmodo. “The question is whether it’s alive.”
Powerful dust storms arise on Mars every few years, but the most recent was perhaps one of the largest on record, according to a NASA release. What began as a small storm back in May soon took over the entire planet.
The nuclear-powered Curiosity rover is doing fine, but scientists were more worried about how the solar-powered Opportunity would fare, with the sun obscured by the thick dust.
It isn’t low power directly that would kill the rover. Opportunity is equipped with a warm electronics box, or WEB, which stores temperature-sensitive equipment and ensures it never drops below -40C. But nighttime temperatures on Mars can reach lower than -100C.
Every piece of electronics inside the box has been tested to -55C, Squyres explained, and the dust storm generally has a moderating effect on temperature, keeping nights warmer. Still, it’s unclear how equipment would behave in temperatures below -55C, or how nearly 15 years of heating and cooling would change the components’ ability to withstand the cold.
NASA will actively listen to the rover — meaning send signals and wait for a response — for a period of 45 days that began this week. But that doesn’t mean they’re giving up after the period is over.
“If the vehicle is actually alive, it should wake up and talk to us on its own,” said Squyres. NASA will await a potential signal until at least January, since perhaps dust has caked onto the solar panels, and a swirling dust devil passing over could clear the panels and awaken the rover. Unlikely, but maybe.
There are now conflicting emotions among scientists. Opportunity has been a wildly successful mission, enduring nearly 15 years when it was only scheduled to last for 90 says.
Squyres, who has been working on the rover mission since 1987, recalled drinks and storytelling when the similarly resilient Spirit rover died after six years of operation in 2010. But Opportunity, unlike Spirit, would be the end of his project. Still, he said, “I always felt there were two honourable ways for the mission to end. Would would be if we simply wore our rover out, and the other would be if Mars killed it.”
Opportunity has made some important observations during its time on the Red Planet. “We found the first sedimentary rocks that showed evidence of liquid water on Mars,” Kirsten Siebach, Martian geologist at Rice University, told Gizmodo.
Then, the rover took a long drive to another crater, where it was able to observe some of the oldest rocks on the planet and help shape our understanding of what Mars once looked like. It has driven 40km across the Martian surface during its operation.
Despite far outlasting expectations, losing Opportunity would be a loss for present-day science. “Opportunity is the only rover exploring the most ancient epoch of Mars history, when strong evidence indicates the planet was warmer and wetter and perhaps not unlike the Earth at that time and when life first got its start here,” Matthew Golombek, Mars Exploration Rover project scientist at the NASA Jet Propulsion Laboratory, told Gizmodo.
Opportunity was in the midst of doing more research, studying small gullies that appear to have been carved by trickles of liquid water. If Opportunity is lost, understanding how these gullies really formed will be one more problem that will go unsolved for now.
Seibach explained that entire careers were built on Opportunity data, and that it’s an asset to have multiple rovers. “If you land one mission on Earth in New York City and try to understand what all of Earth is like, you’ll have a skewed perception,” she said.
We must cross our fingers and hope that the rover reaches back out to us. But if even it doesn’t, the Opportunity mission has been a profound success. “Before we landed, I massively underestimated Mars,” said Squyres. “Mars, it turned out, is way more complicated and interesting than we envisioned.”