LPL
 MAGI Instrumentation Software Laboratory

SSI - Surface Stereo Imager
Image from Mars Pathfinder taken with the IMP, the SSI's ancestor.
The Surface Stereo Imager (SSI) is a multi-spectral, stereo imager based on the design of the Imager for Mars Pathfinder (IMP). The design has been upgraded to incorporate two high-resolution (1024x1024) charge coupled device (CCD) imagers identical to those used on the MER rovers.
The MAGI group is developing the hardware and software for the SSI completely in-house at LPL in close coordination with JPL and Lockheed Martin. The new CCD's in the design will also require new functionality in the electronics, primarily in terms of embedded control logic. The software for the SSI is also new, and is being integrated with functionality already defined for the Robotic Arm Camera (RAC). Although the SSI and the RAC will have separate data paths from an electronics standpoint they will share common functions for image processing and compression, and for downlink back to Earth.
A 3-D design model of the interior of the SSI camera.

A partially assembled SSI camera ready to use for preliminary optical testing. 		In addition to capturing high-resolution stereo images the SSI also incorporates multiple filters for examining surface and atmospheric features at various optical wavelengths. Soon after landing on Mars the SSI will be used to create a panoramic image of the landing site. Stereo images of the digging site for the robotic arm (RA) will be used to create digital elevation models to help guide the digging activities, and multispectral images produced using the various filters will be utilized to help identify local minerals.

The SSI software is designed as a multi-threaded sub-system capable of commanding the CCD imagers and receiving image data, moving the SSI head in both azimuth and elevation, and controlling the internal filter wheel common to both imagers. The control and interface electronics needed to operate the camera was designed by the Phoenix team at the University of Arizona. Uplink of commands and downlink of image and engineering data is handled by the spacecraft's main processor using software supplied by Lockheed Martin and JPL.

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