Where did life exist on Mars? NASA chooses landing site for Curiosity rover
Curiosity rover, formally known as the Mars Science Laboratory, will land at the foot of an 18,000-foot mountain in Gale crater, NASA announced Friday. The mount is expected to yield unparalleled information on where and when life might have existed on Mars.
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The mount pokes above the crater rim surrounding it, suggesting that it formed after the crater did. Moreover, it shows clear signs of sedimentation – meaning that the material that formed it was carried there from somewhere else, either by wind or liquid water.Skip to next paragraph
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And that is its allure.
The 100-mile-wide crater might once have contained a Martian sea, scientists theorize.
Far away on the planes of Meridiani, the Opportunity rover sent to Mars in 2003 has pored over layers of Martian soil reshaped by water – but the craters which it has scoured are comparatively shallow, no more than 60 feet deep. At Gale, the entire mountain could bear testimony to the history and action of liquid water on Mars.
For geologists, this is a virtual pot of gold at the end of the nine-month flight. Sedimentary layers are laid down chronologically, with the oldest layers at the bottom. With perhaps 1,000 feet of layers to drill, prod, and analyze during the first martian year (687 Earth days), geologists think they have a virtual textbook before them in the Gale crater mountain.
“You start at the bottom and go to the top, and it reads like a novel. We think that Gale is going to be a great novel to learn the environmental history” of Mars, he added.
Even from images taken by the orbiting Mars Reconnaissance Orbiter, the story looks intriguing.
- The plain on which the rover will land shows traces of an ancient fluvial fan – evidence that water might once have flowed onto the plains and spread out like the fan-shaped deltas of the Nile or the Mississippi River.
- The rocks at the base of the mountain are clays – rocks typically formed in water.
- Farther up the slope are sulfates – materials also usually formed by interaction with water.
- Higher still on the mountain lie so-called cemented fractures – a landscape that looks vaguely like bubble wrap, with rocky prominences interspersed by straight-line fractures. Dr. Grotzinger said the formations appear to be shaped by water and could include basins that collected mineral-rich water in the distant past.
And beyond is the summit. Team members were careful to stress that summiting the mountain is not a goal of the mission. Scientists are not going to push the pedal and race the rover to the summit to see the sunset. Curiosity might stay in one spot for six months, if it finds something that transforms our understanding of where life could have existed on the Red Planet.
Engineers have given the rover a warranty of two Earth years – after that, any science is a bonus. The Curiosity team would like at least to get the rover to the cemented fractures by then.
But Opportunity’s “primary mission” ran out in 2004, and it’s still trundling across Mars. So there’s hope that Curiosity could be similarly long-lived.
To this end, the science team convened a “Gale Summit Team” to see if it would even be possible to navigate the rover to the top of the mountain. It is. The team found several possible ascent routes. But when Grotzinger talked about the summit, he threw out a hypothetical timeline of 10 years.
If Curiosity were to last that long, a summit run would almost certainly be a victory lap.
Says Grotzinger, Gale crater may have an “exceptionally high diversity of many different kinds of habitable environments.”