Tag Archives: Perseverance Valley

Aligned erosion lines of Perseverance Valley

The uncertainty of science: Last week, while I was flying to Israel, the Opportunity science team announced the discovery of strange aligned erosion lines, what they are calling stone stripes, in Perseverance Valley.

The ground texture seen in recent images from the rover resembles a smudged version of very distinctive stone stripes on some mountain slopes on Earth that result from repeated cycles of freezing and thawing of wet soil. But it might also be due to wind, downhill transport, other processes or a combination.

…On some slopes within the valley, the soil and gravel particles appear to have become organized into narrow rows or corrugations, parallel to the slope, alternating between rows with more gravel and rows with less.

The origin of the whole valley is uncertain. Rover-team scientists are analyzing various clues that suggest actions of water, wind or ice. They are also considering a range of possible explanations for the stripes, and remain uncertain about whether this texture results from processes of relatively modern Mars or a much older Mars.

For those who are regular readers of Behind the Black, you already knew about a variation of this discovery back in November 2017, from my regular rover updates. Then, they discovered aligned groves in the gravel that looked to me like slickensides, erosion patterns produced by glacial activity. The science team told me, however, that they were favoring wind, not ice, as a primary cause, though that conclusion was far from certain.

In the press release last week, they focused more on the aligned erosion patterns in the fine gravel that appear to align perpendicular to the slope. Though they think they have found a comparable Earth-based phenomenon that might explain these patterns, it appears that the science team remains just as unsure of their cause as they are for the rocks.

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Opportunity enters Perseverance Valley

Opportunity in Perseverance Valley

Just prior to the drop in communications this week because of the Sun’s position between the Earth and Mars, Opportunity was ordered down into Perseverance Valley, where it will sit until the return of full communications.

Opportunity entered Perseverance Valley on the west rim of Endeavour crater. The rover is positioned within the valley where she will spend the solar conjunction period.

Solar conjunction is when the Sun comes between Earth and Mars, which occurs about once every 26 months. During this time, there will be diminished communications to Opportunity. More on solar conjunction here: https://mars.jpl.nasa.gov/allaboutmars/nightsky/solar-conjunction/

Two weeks of commanding have been uploaded to the rover to keep her active during solar conjunction with short communications with the Mars orbiters during the period.

The image on the right, reduced to show here, was taken by the rover’s navigation camera looking back uphill at the crater’s crest and the rover’s tracks in the valley. For the scientists the tracks are important because they reveal what the surface of the valley is like, which will help them determine whether it was formed from flowing water, flowing ice, or wind.

Even more significant, this initial drive into the valley means the science team has decided that either the wheel issues in June were not serious enough to prevent them from making this downhill trip, or the science is important enough that they are willing to risk the rover to get that science.

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Opportunity takes panorama at top of Perseverance Valley

On top of Perseverance Valley

During Opportunity’s two week pause in its travels in June as engineers tried to diagnose a problem with its left-front wheel, it took a wide panorama of the surrounding terrain, including the top of Perseverance Valley, released today.

The full panorama, shown above in reduced resolution, is a bit confusing. The head of Perseverance Valley to the northeast is on the right. The view straight ahead looks west, away from the crater. The hill and raising terrain on the left is the crater rim to the south of Perseverance Valley. The panorama is not a complete 360 degree view, as it does not include a direct view to the east and into Endeavour Crater itself.

Be sure and click on the link and look at the full image. The top of the valley is really interesting to view. Was it formed by wind or water or water ice? They hope to find out.

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