Curiosity's camera system makes give Mars rover powerful eyes

Curiosity's cameras give it the ability to relay images both close-up and far off.

Curiosity's cameras give it the ability to relay images both close-up and far off. NASA image

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On Aug. 5, NASA successfully landed Curiosity, the Mars Science Lab rover, at Gale Crater on the planet Mars.

Its 23-month mission is to search for clues of past conditions on Mars that would have supported microbial life. In this new column I will follow Curiosity’s progress by explaining discoveries, examining the instruments used to make these discoveries, and giving a general mission status report.

Curiosity carries the most advanced set of science instruments ever landed on the planet. Some of these instruments will analyze samples of materials drilled from rock or scooped from the ground by the rover’s arm, while others will monitor the atmosphere. Curiosity also has several cameras that can take color still images and color HD video.

Let’s take a closer look at one of the camera systems, MastCam, short for Mast Camera.

This camera system consists of two cameras mounted at the top of a mast that extends about six feet above the surface. The cameras have different focal length lenses.

The high-resolution camera has a 100mm lens (telephoto) while the low-resolution camera has a 35mm lens (standard). Images from these cameras can be stitched together to create panoramas of the landscape. The cameras are also used to study rocks and soil, view frost and weather, and support driving and sampling operations. Here are two examples of how these cameras were used in the last few weeks.

Mars has two small moons named Phobos and Deimos. These moons are much smaller than the Earth’s moon, about the size of asteroids. On Earth, when our Moon passes between the Earth and the Sun we get a solar eclipse, but this event is not limited to the Earth. When Phobos or Deimos passes between Mars and the Sun, they also create solar eclipses. Because Phobos and Deimos are smaller, they only create partial solar eclipses — never a total solar eclipse where the Sun is completely covered. On Sept. 13 the MastCam cameras, using a special filter, were used to take images of the first partial eclipse, as Phobos passed between the Sun and Mars.

NASA will use these images to determine very accurate values for the orbits of the moons. Phobos orbits very close to Mars and appears to be slowly spiraling in toward Mars. These images can be used to determine the exact rates of the orbital changes, and this information can be used to better determine the structure of the moon. Deimos, on the other hand, orbits farther away and is slowly spiraling away from Mars.

On September 2 the MastCam cameras took images of a rock outcrop on the surface. The images of the rocks contained ancient streambed gravels, the first ever seen on Mars. The rounded shape of the rocks indicates that they have been transported over a long distance. The two possible methods of transport are wind and water, but the golf-ball size of the rocks rules out wind as the method. The size of this gravel indicates water moving at about three feet per second, with an ankle- to hip-deep depth. Orbital images show an alluvial fan of material washed down from the crater rim. The large number of channels in the fan indicate several flows over a long period of time, maybe as much as a thousand years. The rocks are cemented together to form what is called a conglomerate, which usually forms in wet environments. A long-flowing stream is an example of a habitable environment.

This is just the beginning. Curiosity has spent most of the time since it landed testing instruments and systems, which are all working well. We are almost ready to start exploring, and the best is yet to come.

Marty Scott is the astronomy instructor at Walla Walla University, and also builds telescopes and works with computer simulations. He can be reached at marty.scott@wallawalla.edu.

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