October 8, 1997 Press Conference - Dr. Wes Ward
"Roadrunner Flats"
This enhanced color image of the Pathfinder landing site shows the
eastern horizon. The elongated, reddish, low contrast region in the distance is
"Roadrunner Flats.".
"Barnacle Bill" Rock
This is an image from the super-pan sequence. Of importance are some of
the features around the rock nicknamed Barnacle Bill in the left foreground. The rock
shows a "streamlined tail" composed of particles deposited by wind on the
leeward (downwind) side of the rock. Also seen is a "moat" around the opposite
(windward) side of the rock where either erosion (or non-deposition) of fine sediment has
occurred. Mars Pathfinder scientist believe that the wind blowing over and around rocks
like Barnacle Bill creates an airflow pattern wherein a buffer zone is formed immediately
upwind of the rock and airflow patterns keep sediment from being deposited directly upwind
of Barnacle Bill. On the downwind side, however, the airflow is complex and a small wake
and tapered "dead air zone" form. Sediment can be deposited within this region
and the shape of the formed deposit corresponds to the airflow patterns that exist behind
the rock. Similar features have been observed at the Viking landing sitess and are thought
to form under high wind conditions during the autumn and winter seasons in the northern
hemisphere. This image mosaic was processed by the U.S. Geological Survey in support of
the NASA/JPL Mars Pathfinder Mars Mission.
"Moe" Rock
A close-up view of the rock "Moe" in the Rock Garden at the
Pathfinder landing site. Moe is a meter-size boulder that, as seen from Sojourner, has a
relatively smooth yet pitted texture upon close examination. Such a texture is seen on
Earth on rocks that have been abraded by wind in a process that is analogous to sand
blasting. This view of Moe shows two faces on the rock, one (left side of the rock) facing
north-northeast and the other (right side) facing east. These two faces are thought to
have been pitted and fluted by strong, "sand"-carrying winds from the
northeast.
"Mermaid Dune"
This pair of images shows a broad view (upper
image) and detailed close-up view (lower image) of the disturbed surface near and on
Mermaid Dune. Seen slightly right of center in the upper image are two diggings by the
rovers' wheel. The uppermost rut is in the surface away from Mermaid and is considered to
be typical of the surface at the landing site. The closer rut represents the surface at
the base of Mermaid on the upwind side. The lower image is an enlargement of the disturbed
Mermaid sediments plus those of the underlying substrate; that is, the ground upon which
the dune lies. Seen in the close-up are at least two types of sediment, one that seems to
be approximately 1.4 cm thick and forms piles with sides sloping at approximately 35
degrees, and another at least 3 cm deep composed of sediment that has a characteristic
slope of 41 degrees when piled. It is apparent in the images that there is a size range of
sediment present in the rut, sediment that ranges from a few millimeters in size down to
below the resolution of the camera.
This is
an image of the rover Sojourner at the feature called Mermaid Dune at the landing site.
Mermaid is thought to be a low, transverse dune ridge, with its long (approximately 2
meter-) axis transverse to the wind, which is thought to come from the lower left of the
image and blow toward the upper right. The rover is facing to the lower left, the
"upwind" direction. The rover's middle wheels are at the crestline of the small
dune, and the rear wheels are on the lee side of the feature. A soil mechanics experiment
was performed to dig into the dune and examine the sediments exposed.
"Stimpy" Rock
The rock "Stimpy" is seen in this
close-up image taken by the Sojourner rover's left front camera on Sol 70 (September 13).
Detailed texture on the rock, such as pits and flutes, are clearly visible.
"Twin Peaks"
This image was taken by the Sojourner rover in the area behind the
"Rock Garden" at the Pathfinder landing site and gives a view of the Martian
surface not seen from the lander. Of note here are several dune-like ridges in the
foreground. These features are less than a meter high but several meters wide. They are
thought to be created by surface winds blowing right to left (approximately northeast to
southwest). These features are called dunes, because of their asymmetry, although the
rover has not examined the sediment within them. Such sediment on Earth would be sand-size
grains less than 1 millimeter in diameter.
"Sediment Tails"
This is a representation of sediment tails noted at
the Mars Pathfinder landing site. The arrows in the figure represent the inferred downwind
direction, based on our understanding of the deposition of very fine sediment around
surface rocks. The inferred wind direction therefore, is from the northeast blowing toward
the southwest. This wind trend matched that of light and dark "streaks" of
sediment in and around Martian craters in the region that were seen by the Viking
spacecraft. The detailed map was prepared by Mars Pathfinder scientists from Arizona State
University on a base image created by MPF scientists from the NASA Ames research
facility.