This article celebrates the continuing exploits of Opportunity, a rover on Mars.
I ividly remember the night it landed. After launching in July 2003, the big night finally came more than seven months later. I was standing at the planetarium’s console, watching the control room at the Jet Propulsion Lab in California and listening as the landing milestones were called out — “parachute deployed,” “airbags inflated,” “we’re bouncing around on Mars!” Then those first images came down from the rover’s front hazcams … OUTCROP! Layers of what later turned out to be salty, lake-deposited sediments on Mars were clearly visible. While orbiting spacecrafts had provided ample evidence for water erosion, this was the first definitive demonstration of sediments deposited by liquid water on Mars. As we have seen from the rovers Spirit and Curiosity, it was not the last.
The prime directive for NASA during that era of Mars exploration was “find the water.” Find the water? The evidence was everywhere Opportunity traveled! From the hematite “blueberry” concretions, to the crosscutting layers in the rock, to sulfate salts, Opportunity’s data describes a much wetter Martian past than was previously thought. Of course, we now want to know what happened to Mars that caused its liquid water to dry up, evaporate or freeze. To help understand this, NASA launched Opportunity to Mars.
How far has she traveled? Opportunity has “run” more than a marathon; the total odometry as of sol 5,144, is 28.2 miles. A sol is the Martian equivalent of an Earth day, approximately 24 hours and 38 minutes, so sol 5,144 means that Opportunity has been on Mars for 5,144 Martian days. The original engineering optimal performance standards for the mission was an estimated to be 90 sols. Opportunity has driven farther than any other vehicle on any extraterrestrial surface, including the moon. Right now, the rover is on the rim of the Endeavor crater exploring sedimentary rocks formed from clay deposition. Clay is usually formed in lake environments, with water at a neutral pH like your drinking water. Of course, the big question still eludes us. Did water flowing on Mars give rise to life as it did on Earth? Everywhere there is liquid water on Earth there is something alive in there, too.
More immediate is not the question of water, but the current threat to Opportunity’s continuing operation, a global sand storm. Opportunity relies on a solar panel for power, and because the storm is blocking the sun, that power has been reduced from 645 watt-hours to less than 22 watt-hours. Opportunity is currently in “deep sleep” mode in which the only power being drawn is by the ship’s clock, which tries to start the radio aboard. If there isn’t enough power, she returns to sleep for another sol. The process will be repeated until the clock itself runs out of power.
Opportunity joins a long, proud tradition of the Jet Propulsion Lab’s robotic explorers that have far exceeded their engineering warranties; in her case, working 58 times longer than her original 90-sol warranty. She joins the Voyagers, Vikings and Cassini, among many others, that have far exceeded their prime missions in the pursuit of knowledge in our solar system.
Opportunity, keep on truckin’!