Engineers back on Earth are hailing the hardy Martian rover. So far, the only answer back is silence. A planet-wide dust storm over the summer silenced Opportunity and turned the barren wasteland into a hazy ball.
Two views of Mars from NASA’s Mars Reconnaissance Orbiter. On the left, Mars as it looked in May. On the right, Mars in July as the dust storm was in full swing. Credits: NASA/JPL-Caltech/MSSS
The last time Opportunity checked in with its team was on June 10, 2018. Since then, it’s been an anxious waiting game for the dust to clear out. And more importantly, for sunlight to start hitting the rover’s solar panels again. Opportunity doesn’t have a nuclear generator powering it like Curiosity. It counts on the sun to power it.
Last week, data from the Mars Color Imager aboard the Mars Reconnaissance Orbiter showed the tau estimate below 1.5 for two straight measurements. Tau is a measurement of the atmosphere’s opacity. It’s used to figure out how much dust and other particles there are in the atmosphere which could impact Opportunity’s ability to recharge its batteries.
Here’s a simulated view showing what different tau measurements would look like from Opportunity’s perspective.
The tau measurements from left to right: 1, 3, 5, 7, 9, 11. This summer’s dust storm had a tau of over 10.8. Credits: NASA/JPL-Caltech/TAMU
What’s going on today with Opportunity
Latest update (September 20): Still no return signal from Opportunity. The mission team is also increasing the number of commands they are sending Opportunity’s way to multiple times a day versus three times a week. A command of what the team describes as “sweep and beeps” is also being sent to possibly fix certain conditions within the mission clock fault.
Critical to operating while in hibernation is the rover’s onboard clock. If the rover doesn’t know what time it is, it doesn’t know when it should be attempting to communicate. The rover can use environmental clues, like an increase in sunlight, to make assumptions about the time.
The 45-day countdown also officially began as of September 12. I should note this isn’t a hard cut-off for when the team will hear back from the rover, but it is when Opportunity has the best chance to call back home. If the 45 days come and go with no response, the team will continue listening through January 2019 just in case.
It’s possible dust from the storm is covering the rover’s solar panels. If that’s the case, Opportunity is going to need a little luck to get out of this jam. A dust devil could pass by and clear the panels. A long shot, but it’s happened before.
We’re only a week into the 45-day active listening period. For a mission only planned to last just over 90 days, I won’t put it past Opportunity to shake off one more Martian obstacle thrown its way.