Intense Mars dust storm puts Opportunity rover in jeopardy
Wednesday, June 13, 2018, 11:58 AM - NASA's Opportunity rover is in jeopardy right now, as an immense dust storm now blankets its location on Mars, cutting off the rover's power supply and causing it to lose contact with Earth.
Mars Exploration Rover Opportunity has been delivering science from the surface of the Red Planet for over 14 years now - an amazing accomplishment for a robot that was only intended for an initial 90 day mission. The rover has set a number of records during this time, including distance driven on another solar system body (beating out Russia's Lunakhov 2 rover on the Moon), and it just set a new one... one that might cost it, dearly.
Right now, the vast plain Opportunity is exploring - Meridiani Planum - is blanketed in the most intense dust storm that NASA scientists have ever witnessed.
The views from Opportunity's cameras have shown the sky filling with dust over the past two weeks. The final frame, on the right, is a simulation based on the rover's data. Credit: NASA/JPL-Caltech/TAMU
The image above shows progressive views from Opportunity's mastcam, as the dust storm intensified since it was first spotted on May 30, 2018. By now, two weeks later, the dust storm is almost completely blotting out the Sun!
Losing the Sun has serious consequences for this solar powered robot.
Up until June 11, according to MER team member Keri Bean, Opportunity was still beeping back at NASA, to let them know that it was doing fine, despite the dust.
However, without enough light reaching its solar panels, Opportunity has apparently powered down, now, as the team announced in a late June 12 update:
NASA engineers attempted to contact the Opportunity rover today but did not hear back from the nearly 15-year old rover. The team is now operating under the assumption that the charge in Opportunity’s batteries has dipped below 24 volts and the rover has entered low power fault mode, a condition where all subsystems, except a mission clock, are turned off. The rover’s mission clock is programmed to wake the computer so it can check power levels.
If the rover’s computer determines that its batteries don't have enough charge, it will again put itself back to sleep. Due to an extreme amount of dust over Perseverance Valley, mission engineers believe it is unlikely the rover has enough sunlight to charge back up for at least the next several days.
Opportunity needs enough power to not only rove the planet and gather science data to send back to Earth, but also to keep its instruments and computers warm during the cold Martian nights. Temperatures on the night side of the planet can dip as low as -80°C even near the equator, where Opportunity is.
There is one benefit of all the dust, however, as Bean pointed out in a tweet on Tuesday:
The latest record Opportunity set? According to Bean, this is the highest "tau" value that has ever been recorded for a Mars dust storm! Tau is a measure of the atmosphere's opacity - that is, how difficult it is to see through it. Thus, the higher the tau value, the harder it is to see.
The previous highest tau value seen on Mars was 9, recorded by the Viking 1 lander, in 1977.
Viking 1 images of the 1977 Mars dust storm. The left image shows a tau opacity of 1. The right image shows a tau opacity of between 5 and 6. Credit: NASA/JPL-Caltech/Olivier de Goursac/The Planetary Society
As of June 12, the tau value recorded during Opportunity's dust storm was estimated at nearly 11!
A Global Storm?
According to NASA, as of June 12, satellites orbiting around Mars show that the storm impacting Opportunity has spread to cover roughly a quarter of the planet!
This animation shows the spread of the June 2018 dust storm across the surface of Mars. The locations of Opportunity and Curiosity are noted. Credits: NASA/JPL-Caltech/MSSS
Even the Curiosity rover, on the other side of the planet, in Gale Crater, is experiencing dusty conditions, based on the latest imagery from the robot's cameras.
Curiosity mastcam images - from June 7, 2018 (Sol 2074) on the left, and June 10, 2018 (Sol 2077) on the right - show the buildup of dust in the air over Gale Crater. Credit: ASA/JPL-Caltech/MSSS
While the insulating factor of the dust will likely keep Opportunity's instruments from suffering damage from the cold, and the volume of dust in the air isn't enough to bury the rover or even produce significant accumulations of dust on or around it, there is are some serious ramification of this storm.
With Opportunity now in lower power mode, if the storm goes on long enough, it may enter a situation known as a "clock fault", where the rover cannot maintain enough power to keep its clock running. If that happens, the rover essentially forgets what time it is, which is a difficult error to recover from, according to the mission team.
Also, once it has passed, the storm may leave Opportunity's solar panels covered in a layer of dust, such that the rover won't be able to gather enough power to recover.
NASA hosted a livestreamed teleconference at 1:30 p.m. EDT, on June 13, to answer questions about the rover and this dust storm. Watch via the embedded video below:
The NASA team does remain confident that Opportunity will weather this storm well, and with its current location - on the slopes of Perseverance Valley - the rover is apparently well-situation for winds to clear off its solar panels once the sky has cleared. We'll just have to wait out this growing storm, which could soon envelope the planet, to tell exactly what Opportunity's situation is, and how well it can recover.