MER-B “Opportunity”, the little rover that could, obliterating all expectations for its longevity and roving for nearly 15 years on the surface of Mars….
The rover went silent back in June as one of Mars’ notorious planetwide dust storms kicked up. Not all of the planet was equally affected, but the spot where Opportunity is trucking around, nicknamed Perseverance Valley for how damn tough this bot has proven to be, was severely affected. It would be nearly as dark as night even in the middle of the day during the worst of the storm. Even a nuclear-powered rover like Curiosity would struggle to be useful in those conditions (it was, ironically, much less dusty in Gale Crater), but for a solar-powered rover, such darkness is disastrous. Opportunity likely completely depleted its batteries. The good news is that it’s summer in Perseverance Valley, and the dust storm acted like a thermal blanket; the rover should have stayed warm enough that its batteries will not have frozen, as likely killed the Spirit rover when it got stuck in a position where it could not receive adequate sunlight over the long winter. The bad news is . . . the rover’s been showing serious signs of age already, and it could be partially buried under dust now. It’s hard to say what condition it’s in.
Still, the storm has been abating. Soon, the tau (a measure of particulates in the atmosphere) is expected to drop below 1.5, at which point there should be enough light to charge the batteries up. It is designed to recover from a complete power loss, and once it has sufficient power in its batteries, it should be able to phone home. And to improve the odds some more, NASA is also sending regular “are you there?” signals to it, while listening for any signals via both the Deep Space Network and the orbiting assets such as Mars Odyssey 2001, Mars Reconnaissance Orbiter, MAVEN, and ESA’s Mars Express, all of which are designed to act as relays for any compatible lander on the surface of Mars.
But NASA cannot afford to listen forever. Once the tau drops below 1.5, a clock will start to tick. They will continue actively pinging the rover for 45 days. After that, a passive listening campaign will continue for another 90 days, in hopes that the upcoming dust devil season may clean off any accumulated dust on the solar panels. But if Opportunity does not respond by the end of that campaign, they may have to finally close the door on this astonishingly successful mission.
So cross your fingers that Oppy calls home! 😉