DigitalCameraReview.com
Camera Systems On Board Mars Rover Curiosity
by Andy Stanton -  8/7/2012

On August 6, 2012, at 1:32 EST, the Mars rover, "Curiosity," landed on Mars at a site called Gale Crater, at the foot of a 3.4 mile (5.5 kilometer) high mountain. It?s practically packed to the gills with cameras, including 12 small imagers for navigating and avoiding hazards and four specialty cameras for taking detailed pictures - the Mars Descent Imager (MARDI), two mast cameras (Mastcams), and the Mars Hand Lens Imager (MAHLI).  Each specialty camera consists of a head (which contains the lens) located outside the body of the rover, and a digital electronics assembly (DEA) located within the rover?s body.  The DEAs include a Bayer Pattern Filter CCD array, which is similar to that used in the sensors of most consumer digital cameras.

The MARDI is designed to take hundreds of color images at a rate of four frames per second during rover?s descent to the martian surface.  For about 100 seconds, from the time the heat shield is jettisoned until touch down, approximately 500 images of 1600 by 1200 pixels in size are obtained to tell the science team exactly where the rover has landed and how far away it may be from key geologic features of interest.  MARDI data is acquired in a form that will produce a high-definition video of the rover?s descent to Mars.

The two Mastcam camera heads are mounted on a bar on the rover?s remote sensing mast, approximately two meters above the ground. They are capable of acquiring natural color images and visible/near-infrared multispectral views (to help decipher mineralogy). Images can also be used to construct stereo representations of the landing site and can acquire video sequences of high definition quality.  Each camera head has a mechanical focus and autofocus capability. One camera head has a 100mm focal length f/10 lens and the other has a 34mm focal length, f/8 lens. Each camera head also has a filter wheel, so that images taken by looking through filters covering different, narrow visible and near-infrared wavelengths can be obtained. The cameras are capable of acquiring 720p high definition video (1280 by 720 pixels) at a rate of about 10 frames per second.

The Mars Hand Lens Imager (MAHLI) is mounted on the turret at the end of a robotic arm. Its purpose is to acquire close-up images of materials on the martian surface.  It has a motor that allows the position of the lenses to be adjusted, so that the camera can focus on its target.  The camera can focus at distances of 22.5 mm (0.9 inch) and infinity.  The MAHLI can acquire multiple images of the same feature at different focus positions and use this to build a best-focus image and a range map of the target.  

It has four white light LEDs and two ultraviolet LEDs to provide illumination of the targets at night or in deep shadow. The ultraviolet LEDs provide an opportunity to look for fluorescent minerals. Stereo views of selected targets can be acquired by taking two images of a target from different angles. The MAHLI has a dust cover to protect the optics from becoming coated by fine dust and dirt. The dust cover has a window through which pictures can be taken if necessary.

Images of Mars are already trickling out. Head over to Nasa's Curiosity image gallery for all of the latest photos.