Image credit: xkcd
Opportunity celebrated its ninth anniversary on Mars today:
PASADENA, Calif. -- NASA's Mars Exploration Rover Opportunity, one of the twin rovers that bounced to airbag-cushioned safe landings on Mars nine years ago this week, is currently examining veined rocks on the rim of an ancient crater.
Opportunity has driven 22.03 miles (35.46 kilometers) since it landed in the Meridiani Planum region of Mars on Jan. 24, 2004, PST (Jan. 25, Universal Time). Its original assignment was to keep working for three months, drive about 2,000 feet (600 meters) and provide the tools for researchers to investigate whether the area's environment had ever been wet. It landed in a backyard-size bowl, Eagle Crater. During those first three months, it transmitted back to Earth evidence that water long ago soaked the ground and flowed across the surface.
Since then, the mission's team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., has driven Opportunity across the plains of Meridiani to successively larger craters for access to material naturally exposed from deeper, older layers of Martian history.
Opportunity has operated on Mars 36 times longer than the three months planned as its prime mission.
NASA's Veteran Mars Rover Ready to Start 10th Year
Maybe the best illustration of what that means is provided by this self portrait of the rover, taken almost a year ago:
Opportunity has worked through four Martian southern hemisphere winters since it landed in in January 2004 about 14 miles (23 kilometers) northwest of its current location. Closer to the equator than its twin rover, Spirit, Opportunity has not needed to stay on a sun-facing slope during the previous winters. Now, however, Opportunity's solar panels carry a thicker coating of dust, and the team is using a strategy employed for three winters with Spirit: staying on a sun-facing slope. The sun will pass relatively low in the northern sky from the rover's perspective for several months of shortened daylight before and after the southern Mars winter solstice on March 30, 2012. Opportunity is conducting research while located on the north-facing slope of a site called "Greeley Haven."
Dusty Mars Rover's Self-Portrait
Despite choking dust and the fierce winds that deposited that dust, the little rover is continuing to explore the Martian surface. As Space.com notes, Opportunity has now logged more miles than all but one extraterrestrial vehicle:
In late September 2006, Opportunity wheeled up to Victoria Crater after 21 months on the road. It circled the rim for a few months snapping pictures and getting a close look at some layered rocks surrounding the crater. NASA then made a gutsy decision in June 2007 to take Opportunity inside the crater. It was a risk to the rover as it might not have been able to climb up again, but NASA said the science was worth it.
Opportunity climbed out successfully in August 2008 and began a gradual journey to Endeavour, an incredible 13 miles (21 km) away. It took about three years to get there, as the rover was stopping to look at interesting science targets on the way. But Opportunity successfully arrived in August 2011.
Opportunity is still doing science there today, beaming back findings such as a mineral vein deposited by water. The little rover has completed nearly a marathon's worth of mileage on Mars.
Opportunity: Longest-Running Mars Rover
A chart at that link shows the distances driven by all the vehicles we humans have sent to other planets. Only one, the Soviet Union's Lunokhod 2 Moon rover, has driven significantly more than Opportunity.
Opportunity's travels have brought it to the Matijevic Hill:
mage credit: NASA/JPL-Caltech/Cornell/Arizona State Univ.
As NASA's Mars Exploration Rover Opportunity neared the ninth anniversary of its landing on Mars, the rover was working in the 'Matijevic Hill' area seen in this view from Opportunity's panoramic camera (Pancam). Opportunity landed Jan. 24, 2004, PST (Jan. 25 UTC). The landing site was about 12 miles (19 kilometers), straight-line distance, or about 22 miles (35.5 kilometers) driving-route distance, from this location on the western rim of Endeavour Crater.
Matijevic Hill is an area within the "Cape York" segment of Endeavour's rim where clay minerals have been detected from orbit.
'Matijevic Hill' Panorama for Rover's Ninth Anniversary
The rover is now investigating that clay formation, which is interesting because clay is one of the substrates that may have aided the development of life on Earth:
[HHMI scientist Jack W.] Szostak and his colleagues were prompted to perform their experiments by the earlier work of other researchers who had found that clays could catalyze the chemical reactions needed to construct RNA from building blocks called nucleotides. They reasoned that if clays could foster the formation of vesicles, it would not be inconceivable that clay particles that had RNA on their surface could end up inside such vesicles. If that were true, the result would offer conditions amenable to the eventual evolution of living cells that could self-reproduce.
In their experiments, Szostak and his colleagues found that adding small quantities of the clay, montmorillonite, to fatty acid micelles greatly accelerated the formation of vesicles. They also discovered that many other substances with negatively-charged surfaces also catalyzed formation of vesicles.
Clays May Have Aided Formation of Primordial Cells
Whether life ever existed on Mars is a question that biologists will be fascinated to learn, because right now we only know one planet where it has managed to appear. How it can appear, and under what circumstances, will be a fascinating subject in the years ahead.
Meanwhile, though, Opportunity is pressing on, far exceeding its original design goals, and giving us far more than we bargained for.
UPDATE/Afterword: Corrected the first image caption - it's been three years, not two, since Spirit went to the great Barsoom in the sky. Also, don't forget that you can click on the images to see them at 1600x1200 pixel resolution. Full size images are available at the image credit links.