Photos give scientists panoramic view on Mars

The rock outcrop Kimberly is seen in this panoramic photo shot on Mars.

The rock outcrop Kimberly is seen in this panoramic photo shot on Mars. Courtesy photo

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Curiosity is currently at Kimberly, a science stop on the way to Mount Sharp. In charting the route to Mount Sharp, mission planners saw this spot as the best science stop along the way.

Kimberly is a rock outcrop with several distinctly different expressions of exposed rock. There is a striated layer that can be seen from orbit. On top of this layer is a non-striated layer, and on top of that there is a sandy layer.

There are also three buttes that mark the edges of the outcrop. Two on the north edge are called Christine and Joseph, and one on the south edge is called Remarkable.

When Curiosity arrived at Kimberly, like all good geologists she walked the site to get a complete overview of what was there. Curiosity spent a week working her way down the east side of the outcrop from north to south.

To get the overview, Curiosity used her cameras and took an enormous number of photos as she traveled down the outcrop.

One of the most helpful types of image for a site overview is the panorama. Color panoramas are made using one or both of Curiosity’s Mastcam cameras.

To create these panoramas, multiple images are taken in succession, with the camera rotated horizontally between each image. The camera can then be rotated vertically and another series of images taken.

The individual frames are then download to Earth, where they are stitched together to create a single panoramic image.

A panorama taken on sol 590 (April 3) contained 31 columns and six rows of images, so nearly 200 images were used to create this panorama.

If the series of images are taken with both Mastcam cameras, NASA technicians can create stereo, 3-D panoramas with a little bit of work.

The right camera has a 5.1-degree field of view, while the left camera has a 15-degree field of view. This means it takes a three-by-three array of right camera images to cover a single left camera image, so the technicians crop top and bottom of the left camera images to approximate the coverage of the right.

By cropping the images before they are downloaded to Earth, more images can be downloaded in the same amount of time.

When an image is taken, a tiny, low-resolution thumbnail image is downloaded first. This is a small file, so the download time is short, but it gives analysts an idea of what is in the image.

Because it takes weeks to download all the full-resolution images taken at Kimberly, Curiosity stores them until they make their way into the download queue.

The controllers on Earth can also tell Curiosity the order in which to send the images. If they need an image to make a tactical decision, they can give the image a higher priority so it will be downloaded sooner.

An example of that is a panorama taken with the right Mastcam of Mount Remarkable that was taken on sol 595 (April 8).

You can view this panorama here.

Panoramas can also be created using the black-and-white Navcam cameras. There are two sets of Navcam cameras, one set next to the outside edge of each Mastcam camera. Each of these stereo pairs has a 45-degree field of view.

As the name implies, the primary use of the Navcam cameras is to analyze the surrounding terrain and select targets for further observation by the rover’s science instruments. The black-and-white images obtained with these cameras create smaller files that are faster to download to Earth.

You can view a Navcam Kimberly image at the top of this story.

As Curiosity drove down the eastern edge of Kimberly, it completed several mid-drive stereo-imaging stops using both the Mastcam and Navcam cameras. These multiple-stop drives are quite complex to plan and have been rarely done so far.

It was done at Kimberly to help determine the process that formed the striated layer. Three-dimensional mapping from various angles will hopefully reveal subtle patterns that might distinguish between different kinds of fluvial environments that laid down those beds.

Curiosity has also used many of its sciences instruments to gather other data about Kimberly. With this data and the many images it has collected, Curiosity has done a site overview that would make an Earth-based geologist proud.

Marty Scott is the astronomy instructor at Walla Walla University. He can be reached at marty.scott@wallawalla.edu.

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