QUESTION:
How will the quality of the images from the Martian surface compare with
what was beamed backed from the Viking mission? I imagine that with 20 extra
years of technological improvements, imaging must have made significant
advancements.

ANSWER from John Wellman:
The Mars Pathfinder mission was originally conceived to demonstrate a
low-cost way of getting to the Martian surface. The original guidelines for
the camera were to provide a simple (monoscopic) panorama of the surface.
When NASA asked for proposals to build the camera we specified that the
resolution should be comparable to the Viking lander cameras and listed
stereo coverage and color as desirable capabilities if they could be
provided within a very limited cost cap. I am pleased to say that an
ingenious team from the University of Arizona, supported by the Max Planck
Institute in Germany has delivered a camera with 1 milliradian resolution
(Viking black and white was 0.7; color, 1.4) that includes 24 filter
positions and stereo capability. Thus Pathfinder has an unprecedented
multispectral capability with 12 distinct spectral filters for geology,
eight for atmospheric studies and a closeup lens position for viewing dust
accumulations on a magnetic target (some filter positions are duplicated for
the camera's two eyes for the purpose of stereo imaging). The camera has
12-bit encoding (compared to Viking's 6-bit), so that the radiometric
accuracy is greatly enhanced. Finally, the camera software includes several
data compression algorithms to take maximum advantage of the telemetry rates
available.

Pathfinder is expected to return a complete panorama of the surface in color
and in stereo. In addition, its scientific capabilities will be used to
study the spectra of surface rocks and minerals, the optical characteristics
of the atmosphere and the magnetic properties of wind-blown dust.

As the questioner correctly asserts, this improved set of imaging
capabilities was made possible at very reasonable cost by technology
improvements, most notably, the use of a high-quality imaging charge coupled
device (CCD) detector.

--John Wellman, Mars Pathfinder Science and Instruments Manager