NASA has said that it expects its Opportunity rover to survive on Mars – despite being caught in the middle of the biggest dust storm ever seen on the Red Planet.
In a press conference yesterday, the agency confirmed that the 15-year-old rover had “fallen asleep” due to extremely low power levels as the storm blotted out the Sun. Now all the team can do is wait until it wakes up autonomously and sends a signal back to Earth.
“We should be able to ride out the storm,” John Callas, Opportunity project manager at NASA's Jet Propulsion Laboratory in Pasadena, California, said at the conference. “When the skies clear and the rover begins to power up, it should begin to communicate with us.”
This storm was first spotted on Mars in late May, and has since grown in size to cover an area bigger than North America and Russia combined, accounting for a quarter of the planet. It’s so big that it’s even darkening the skies above the Curiosity rover on the other side of the planet.
Dust storms like these occur when the Sun’s rays heat the atmosphere and dust is lifted off the ground. Scientists aren’t quite sure why they can become so large, but weirdly it looks like a lot of them originate from the same place, the Hellas impact basin (although this one did not).
The grains in a dust storm like this are incredibly fine, so the rover is not expected to get buried in dust or even covered to a significant degree. The big danger, though, is that the dust blocks out the Sun and reduces the amount of solar power available to the rover, meaning it can’t charge up or stay warm.
The last signal from Opportunity was received on June 10, after which its power was too low to operate, and it switched to a “low power fault mode”. In this mode, it uses all its available power to operate a mission clock, which regularly checks to see if the rover is able to communicate again. If not, it goes back to sleep.
And the problem here is that Opportunity needs to keep warm. If the temperature drops below -55°C (-67°F), the rover is not expected to survive if it can’t switch on. Mars Program Office chief scientist Rich Zurek, however, said the coldest temperature they expected was -36°C (-33°F).
“So we think we can ride this out for a while,” he said.
How long is a while? That’s not clear yet. If the storm continues to grow and encircles the entire planet, it could be a month or more before it dissipates. Fortunately, it looks like Opportunity will be able to hang on, unless temperatures drop dramatically.