2007 Martian Dust Storm Strengthens
Published on Jul 20, 2007 at 3:28 pm.
2 Comments.
Filed under Mars.
A couple of weeks ago, I wrote about a global dust storm on Mars that was of concern to the scientists at NASA’s Jet Propulsion Laboratory. Well, the dust storm just keeps getting stronger.
The image here shows the worsening skies as seen from the Mars Exploration Rover Opportunity, located at Meridiani Planum. The condition is nearly as bad with the rover Spirit, located in Gusev Crater. The situation is so bad that, according to a JPL news release, about 99% of the direct sunlight to the rover has been blocked by the dust. At least some indirect sunlight is reaching the rovers, but still the solar panels are providing less than 20% of the electricity that they were before the dust storm hit. Worse, the solar panels for Opportunity are providing only 98% of the electrical energy that the rover is using in is sleep mode! It can keep this up for a couple weeks more, as long as things don’t get worse, but if conditions don’t improve, the rovers may be lost. The image below shows the changes on Mars over a one month time period as seen from an orbiter.
The rovers need electrical energy to stay alive. Certainly, they need electricity to operate radios, to move around, and to conduct science experiments. But, they also need electricity to heat themselves. At night it gets VERY cold on Mars, even during the dust storm. It gets cold enough to damage, perhaps critically, many of the rover’s components. To save electrical energy, for some time now JPL has not been driving the rovers, and science measurements have also been suspended. Now, steps are being taken to curtain communication, which also uses electrical energy. This is the first time that either rover has ever had communications cut to conserve energy.
While no one wants the rovers to fail, even if they were to quit functioning during the dust storm, they would have been fantastic successes. They landed on Mars in January, 2004, with a planned mission length of about 3 months. They were still functioning after those three months, so the mission was extended. Still, it was anticipated that after a year they’d be dead. Now, it is three and a half years later, and they are still going strong (or at least they were before the dust storm hit). Granted, they’ve been showing their age, and not all systems are functioning as they once did, but the rovers have not failed yet. And, even in the current situation, they are not dead yet. The dust storm is very worrisome to the folks at JPL, but they are not yet in a panic and though the situation is quite serious, they don’t seem to regard this quite yet as a crisis (though that may change if the dust storm either gets worse or doesn’t let up soon). They are optimistic that they can weather the storm, but really no one knows how long the dust storm will last or how bad it will be.
Mars is known to have these global dust storms from time to time. They get going and they cover the entire planet. And, this is not the first time that a dust storm has threatened a mission to Mars. In November 1971, the Mariner 9 spacecraft arrived at Mars. Mariner 9 was the first spacecraft to orbit another planet, and it had been launched earlier that year. However, while Mariner 9 was on the way to Mars, a massive dust storm came that blotted out the surface. These Martian dust storms sometimes last days, weeks, or even months. It became a waiting game. Which would give out first, the dust storm or the spacecraft? As it turned out, the dust settled before the spacecraft quit functioning, and Mariner 9 made major discoveries about Mars, such as that planet’s massive volcanoes, the Valles Marineris (a massive series of rifts and canyons stretching much of the way across Mars), and images suggesting possible water erosion in Mars’ distant past.
So, now we are again in a waiting game. Which fails first, the dust storm or the batteries on the rovers? I would like to see the rovers survive, particularly since they have spent the last three and a half years driving from where they landed to some very interesting surface features that would likely provide a wealth of scientific data if we could study them. But, as I said, the rovers have already lasted far beyond what was expected, so even if they fail now, they’ve had a wonderful run and have already returned more data from the surface of Mars than anyone had even remotely hoped for before they landed.
Dust storms of this magnitude are not unheard of on Mars, but they don’t occur all the time, either. The last one that was this bad was in 2001. There were a couple of these major storms in the 1970s. So, you expect them every decade or so (but irregularly spaced, it seems). We simply have been lucky with our exploration of Mars. But, clearly, if the dust storms can block out 90%, 95%, or even 99% of the sunlight, they are something to contend with, especially if they can last for weeks or months at a time. Future generations of rovers are supposedly being designed to weather storms of this magnitude (though even they may have a tough time if one of the truly monster Martian dust storms gets fired up). But, this also raises concern for NASA’s plans for a future manned mission to Mars. Manned missions need far more electrical energy than unmanned missions, and the manned missions cannot simply be put into “sleep” mode for days or weeks at a time to save electricity. This is one reason that there is talk of using nuclear energy for manned missions. Then, it would not be susceptible to Martian dust storms cutting power. But, there is another concern. All that dust gets everywhere. Martian dust is composed of very small particles, which might tend to get into any seams and joints and begin to wear away at them. The Martian dust would stick to everything, likely, and any astronauts leaving their habitat would carry the dust back with them into the habitat. That dust would then infiltrate the air handlers and be distributed around the habitat, including into the astronaut’s lungs. The tiny particles might stick in the lungs causing long term damage.
And, as of yet, we do not understand Martian climate and weather enough to be able to predict these dust storms or to predict their magnitude once they get going. So, we just have to wait them out. That would be nerve wracking for astronauts on a manned mission. It is already nerve wracking for the scientists at JPL. All we can do right now is hope that the rovers manage to weather the dust storm.
-Astroprof
Images courtesy of NASA
A Ler…-- Rastos de Luz on July 20, 2007 at 4:25 pm: 1
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Gordon R. Vaughan on July 20, 2007 at 11:40 pm: 2
Yeah, Mariner 9 was the first planetary mission I was old enough to remember. I didn’t learn until years later that there was a companion, Mariner 8, but it ended up in the Atlantic Ocean.
NASA took a tremendous public relations hit from the dust storm delays. In 1971 the Apollo program was getting cut, aerospace jobs were going fast, and NASA really needed a boost from a successful Mars mission.
Mariner 9 was in the end successful, but by the time the dust subsided, the press had lost interest. The public’s interest in space wasn’t really re-kindled until the Viking landers in 1976.
That was short-lived, however, because they supposedly failed to find signs of life (though that is now being questioned). It wasn’t really until the Voyager 1 (originally designated Mariner 11) Saturn encounter in late 1980 that people really started getting excited about space again.
STS-1 followed just a few months later. Of course, Mariner 10 had gone to Mercury and Venus some years earlier, but missions to those planets have never drawn anything like the public interest in missions to Mars and Saturn.