On Mars, NASA’s Opportunity rover has run out of so much power it can’t communicate with Earth anymore — but that doesn’t mean the vehicle is dead yet. The robot is in a deep sleep, thanks to a particularly nasty dust storm that’s blocking sunlight from hitting its solar panels. NASA engineers are optimistic that the rover will be able to wake up and do science again once the storm has cleared up. But they’re still worried.
“It’s like you have a loved one in a coma in the hospital,” John Callas, the project manager for Opportunity at NASA’s Jet Propulsion Laboratory, said during a press conference. “You have the doctors telling you that, ‘Okay, you just have to give it time, and she’ll wake up.’ All the vital signs are good, so it’s just waiting it out.” He added: "By no means are we out of the woods here.”
The last time anyone heard from Opportunity was on the morning of June 10th, when it sent a radio transmission indicating that its energy production was at an all-time low. That prompted NASA to declare a “spacecraft emergency,” since Opportunity wasn’t generating enough power to continue doing its most basic functions. When NASA tried contacting Opportunity yesterday, June 12th, the rover didn’t reply. That means it’s gone into a very low power mode.
So what now? Basically NASA has to ride the storm out, just like the rover. Opportunity will likely remain quiet until the dust dissipates enough for the Sun to reemerge. When a sufficient amount of light hits Opportunity’s solar panels again, the rover can charge its internal battery and try to wake itself back up. If that works, it will then try to communicate with Earth again. “At this point, we’re in a waiting mode,” said Callas. “We’re listening every day for possible signals from the rover and be prepared to respond to that.”
It’s possible NASA could be waiting for a while, though. The dust storm has only been growing over the last couple of weeks, and it now covers nearly a quarter of Mars’ surface. Soon it could encircle the entire planet, potentially lasting for a month or more. And this storm has essentially turned day into night on the Red Planet; Opportunity may be without sunlight for quite some time.
The biggest concern for NASA is Opportunity’s temperature. Just moving around and doing tasks heats up the vehicle, but it grows colder when it’s still. And if it gets too cold, it runs the risk of breaking. Fortunately, the rover is equipped with eight heating units made out of plutonium that generate a tiny amount of thermal energy. Plus, it’s getting close to summertime at Opportunity’s location and dust storms warm up Mars. The rover’s designed to handle temperatures as low as -67 degrees Fahrenheit (-55 degrees Celsius), and NASA thinks Opportunity’s temperatures will only reach -32.8 degrees Fahrenheit (-36 degrees Celsius). “We think we can ride this out for a while,” said Callas.
Right now, any power that Opportunity generates is going straight to its internal clock. “It’s disconnected its battery from the rest of the electronics and only the clock is running in the background,” Mike Seibert, the former flight director for Opportunity, tells The Verge. That’s because the rover is going to need to know what time it is when the Sun comes back out again. Once Opportunity gets enough light on its panels, it will charge a bit, hook its battery back up to the electronics, and then try to wake itself up each day when the Sun is at its highest point in the sky, called solar noon. That’s when NASA is going to try to communicate with Opportunity as the storm clears away.
Things get tricky, though, if Opportunity can’t generate enough power to keep the clock up and running. If the rover’s sense of time is thrown off, it may wake up at the wrong time. For instance, it could try to wake up at a time when the Sun isn’t out, thinking it’s actually noon. If that happens, Opportunity will notice there’s no light and start napping again to conserve power. It will then pick another time to wake up less than a day later, hopefully when the Sun is shining. It will keep doing this until it establishes a connection with Earth. That means NASA will need to ping Opportunity frequently to coincide with one of these more random windows. In preparation, the space agency has requested more time with the Deep Space Network — an international array of communications antennas on Earth — to help establish a signal with the rover.
Overall, the team thinks they’ll be able to establish a connection with Opportunity again. It’s possible bits of dust might contaminate Opportunity’s camera lenses when the storm is over, according to Seibert. But the rover has lasted for more than 14 years on the Martian surface, and its day might not be over yet. “Mars will have to try harder next time to kill Opportunity,” says Seibert.