If you felt a bit apprehensive about this morning’s media teleconference from NASA, you’re not the only one. The very long-lived Opportunity is facing its most dire predicament yet – a raging dust storm that has virtually turned day into night at its current location. This is, of course, cause for a great deal of concern, but it seems like, as of now, that the rover has a good chance of riding it out. It is by no means out of the woods yet, but the mission team have confidence in their plucky rover, which has already far outlived its primary mission of 90 sols – by nearly 15 years!
Dust storms are fairly common on Mars, and Opportunity has experienced them before, and survived. This current one however is much more intense, hence the major concerns on the part of the mission team. The storm was first detected forming on May 30, and has grown considerably since then. It currently covers 14-million square miles (35-million square kilometers) – about a quarter of the planet.
The rover has now apparently put it itself to sleep, as designed to do, to hopefully ride out the storm. It is in low power fault mode, where all subsystems are turned off except for the mission clock. An attempt to contact the rover yesterday failed, but that would be expected in these circumstances. The mission clock can intermittently wake the rover’s computer to check power levels, which are now thought to be below 24 volts.
Dust storms are dangerous for rovers like Opportunity and Spirit, which are powered by solar panels. The Curiosity rover however, is nuclear-powered, so is much more able to safely survive such storms. Curiosity, 1,367 miles (2,200 kilometres) away in Gale crater, is witnessing the storm also, however, with skies darkening, but not nearly as much yet as at Opportunity’s location. This storm is likely to become a global dust storm; the last ones observed were in 2001 and 2007. Some researchers had predicted a global dust storm for this year, and it looks like they might be right.
The current dust storm is much worse than the one Opportunity endured in 2007. Then, the atmosphere had a tau(opacity level) somewhere above 5.5. But now, as of last Sunday morning, the tau was at 10.8. The massive dust storm has virtually changed day into night for the time being. The storm in 2007 was larger, but less intense. While dust storms on Mars are relatively infrequent, they can form quite suddenly and persist for weeks or months. In terms of wind, however, they are not as devastating as depicted on The Martian, due to the atmosphere being so thin. It was also noted during the teleconference that there is no worry about the rover being buried under sand, since even during a storm of this magnitude, only a very thin coating of dust would result, about one layer of dust particles thick.
One good thing to note is that temperatures are a bit warmer right now than they were in 2007, as the region moves into summer, which helps to keep the rover from freezing. The latest data transmission from Opportunity showed the rover’s temperature to be about minus 20 degrees Fahrenheit (minus 29 degrees Celsius). Even though the dust blocks out sunlight, it raises the ambient temperature by absorbing heat. As explained by Scott Maxwell on Twitter, Opportunity should be able to survive this storm:
“Opportunity designed for -55C. Minimum flight allowable temp is -40C. With storm blanket + summer temps (+ eight tiny heaters inside chassis), expect steady state of -36C – so should be able to ride this out.”
According to John Callas, Opportunity project manager, on Twitter, as quoted by Emily Lakdawalla, “We’re in a waiting mode, listening every day. Going forward, our concern is temperature on the rover, because it’s inactive. Good news is that dust storm keeps things warmer, and it’s going into summer season. We believe rover should stay above min operating temps.”
Right now, many eyes are on the dust storm.
“A flotilla of NASA spacecraft at Mars are measuring the ongoing storm in greater detail than ever before. This is an unprecedented opportunity to learn more about Mars,” said Jim Watzin, head of the Mars exploration programme at NASA’s headquarters in Washington DC.
Opportunity has helped to revolutionize our knowledge about Mars, and was the first mission to find evidence for ancient salty playa lakes on the planet, showing that habitable conditions used to exist there, at least for microbes. It has explored vast stretches of rolling sand dunes and steep cliffs on the edges of massive craters. It also found the now-famous “blueberries,” hematite concretions which formed billions of years ago when there used to be a lot more water in the region than there is now. Most recently, the rover has been studying was is thought to be an ancient water-carved gully called Perseverance Valley on the edge of Endeavour crater.
It is expected, and hoped, that the storm will be over by the time the InSight spacecraft lands in November. But even if there is still some dust activity, InSight should still be able to land safely.
As of right now, the rover team is concerned but hopeful. As Callas said, “It is concerning. This team has a very strong bond with the rover, we have a very tight emotional connection with it. We anthropomorphize this rover. It’s like we have a loved one in a coma in the hospital.”
If all goes well, the rover should start to recharge again once the storm clears and power levels go back up. So let’s hope that Opportunity will awaken again from its sleep, and continue the amazing journey that it has been on all these years.