On May 30, NASA first detected the swirling dust storm that would soon enshroud all of Mars. Today, that planet-wide dust storm is dying down. And soon, the skies should clear enough for the hardy Opportunity rover to recharge its batteries.
“The Sun is breaking through the haze over Perseverance Valley, and soon there will be enough sunlight present that Opportunity should be able to recharge its batteries,” John Callas, Opportunity project manager at JPL, said in a statement. “When the tau level [a measure of the amount of particulate matter in the Martian sky] dips below 1.5, we will begin a period of actively attempting to communicate with the rover by sending it commands via the antennas of NASA’s Deep Space Network. Assuming that we hear back from Opportunity, we will begin the process of discerning its status and bringing it back online.”
Let’s break down what’s happening right now and the plan moving forward.
Waiting on a beep
Since last hearing from Opportunity on June 10, the mission team has sent a command to the rover three times a week. If the rover is awake, it’ll respond with a beep. So far, only silence. But that is to be expected. While the skies are clearing over Opportunity, the dust hanging in the atmosphere is still too thick for enough sunlight to hit the rover’s solar panels.
The team continues to monitor the skies above Opportunity with the help of NASA’s Mars Reconnaissance Orbiter (MRO). Using data from MRO’s Mars Color Imager, engineers can estimate how clear the skies over the rover are. The good news is no dust storms are brewing within 1,900 miles of Opportunity according to MRO Project Scientist Rich Zurek.
If Opportunity doesn’t respond in the next 45 days (starting when the skies are clear enough to recharge the batteries), then it’s likely the dust storm (and Martian cold) triggered a fault within the rover that it can’t recover from.
But this isn’t a hard cutoff. “At that point our active phase of reaching out to Opportunity will be at an end,” says Callas. “However, in the unlikely chance that there is a large amount of dust sitting on the solar arrays that is blocking the Sun’s energy, we will continue passive listening efforts for several months.”
A dust devil could cruise by close enough to clear the dust off the solar panels. Yep, this can happen. Back in 2004, battery levels on Opportunity increased several percent in a single night when the exact opposite should happen. Here’s one Opportunity photographed back in February 2017.
Opportunity’s tough recovery
Even if Opportunity sends a beep back to Earth, mission engineers won’t know if the rover can resume normal activities. The rover wasn’t built to weather dust storms. Its primary mission was only meant for 90 days. 14 years later and the mission team is crossing their fingers their rover will radio back once more.
“In a situation like this you hope for the best but plan for all eventualities,” said Callas. “We are pulling for our tenacious rover to pull her feet from the fire one more time. And if she does, we will be there to hear her.”
First, the team has to make contact. After that, they’ll run a full diagnostic check to see how the rover is doing. Opportunity has shrugged off a lot of obstacles in its decade-plus visit to the red planet. We’ll see if it can add a planet-wide dust storm to the list.