The CCD imager electronics for the mars pathfinder and mars surveyor cameras

The Mars pathfinder stereo camera and both cameras on the Mars surveyor lander use CCD detectors for image acquisition. The frame transfer type CCD's were produced by Loral for space applications under contract from MPAE. A detector consists of two sections of 256 lines and 512 columns each. Pixels in the image section contain an anti-blooming structure to remove excessive charge from overexposure. The storage section is covered by a metal mask. Rapid charge transfer allows operation without shutter. The CCD's are qualified for operations at very low temperatures. In the course of the development, the performance of the CCD detectors was significantly improved by a technological change in the substrate grounding. For several reasons, the design of the cameras require a separation of the CCD's from the readout electronics. The electronics were designed to operate the CCD's via a cable of up to 4 m length without performance loss. Low read noise and a resolution of 12 bits could be achieved with a very low power consumption of approximately 1.1 W.