Mars Pathfinder's Imaging Instrument Delivered

September 4, 1994


Mars Pathfinder's Imaging Instrument Delivered
Date: 4 Sep 1994
Organization: Jet Propulsion Laboratory


>From the "JPL Universe"
July 29, 1994

Mars Pathfinder's faster, better, cheaper imaging model delivered

By KARRE MARINO

   JPL's Mars Pathfinder project has taken delivery of the
spacecraft's imager engineering model from the University of
Arizona.

   According to John Wellman, science and instruments manager for
Pathfinder, what makes the hardware and its receipt unique is that
the imager is a prime example of the "faster, better, cheaper" way
to do business.

   Acquiring an imaging system that was low in cost but high in
quality drove the process.

   "We are trying to find low-cost ways to do good planetary
exploration, which led to our working with a university team
supported by foreign contributors and an accelerated announcement-
of-opportunity process," Wellman explained.

   "We helped NASA to put out the announcement in a hurry and
received responses quickly," he added, noting that this process
generally takes more than a year, but in light of the new "faster,
better, cheaper" mandate, Pathfinder managed it in about six
months.

   The University of Arizona's Peter Smith was selected as the
system's principal investigator, with contributions from a German
and Dutch firm, and Martin Marietta of Denver.

   The German contribution came from the Max Planck Institute near
Hanover--which offered a charged-coupled device as part of the
flight hardware--at no cost, with the provision that they would
have rights to participate in data analysis as part of the science
team.

   The Neils Bohr Institute in Copenhagen "provided magnetic
targets that are used for evaluating the collection of windblown
dust on the Martian surface," Wellman explained. The camera itself
was built by Martin Marietta.

   Wellman pointed to another major difference in the contract
between JPL and the prime contractor, the University of Arizona:
cost caps. "We set baseline requirements in the announcement, and
the contractor had to propose to do the best possible science
within the cost. A reserve was available, but they had to manage
it." Should the reserve have been depleted, he said, the
contractor would have had to descope the experiment.

   Along with delivery of the imager came camera-control software,
several data-compression algorithms and bench-checkout equipment,
which Wellman described as "electronics that simulate the lander,
allowing us to operate the camera as if it were connected to the
real Pathfinder lander. It also collects data from the camera."

   End-to-end system tests with JPL's Flight System Testbed, he
said, are currently under way.

   Wellman pointed out another remarkable facet of the venture:
"Arizona didn't receive its funds until November 1993, and the
team delivered the imager on schedule. That's impressive for new
flight instrument delivery.

   "And the quality of the hardware is so good that we could keep
it and potentially use it for spare parts."

   He praised the timely delivery as having resulted from the
university delivering exactly what it proposed. "This worked
because the project made so few changes. We didn't want to cause
ourselves any problems." Such an attitude helps the contractor
deliver, he agreed.

   An essential factor in the initial agreement was the project's
recognizing that the "interface between the spacecraft and the
camera was important," said Wellman. "We've gone further in trying
to make the interface work smoothly."

   Such a concept is new to Pathfinder, which will realize a "more
highly integrated camera control, provided by the spacecraft's
computer.

   "The camera electronics boards plug directly into the
spacecraft's integrated electronics module. That allows us to do
two things: We can use an existing commercial interface protocol
for all subsystems that talk to the central computer, and we can
share the capabilities of this more powerful computer."

   Such an approach makes possible the integration of the camera
with the central computer and the rest of the spacecraft's
subsystems in 30 minutes.

   Previous cameras, he explained, containing their own computers,
have required considerably more time to complete the integration
process.

   The imager, Wellman said, is a stereo imaging system with color
capability provided by a set of selectable filters for each of the
two camera channels. This allows the system to photograph the
Martian surface after landing.

   "The 24 color filters will help the project gain--in greater
detail than possible with the Viking lander camera--insight into
the surface's mineralogy," he said.

   The stereo capability is used to understand the shape of Mars'
surface and rock formations, and will also control the rover as it
explores the red planet.

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