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Figure 1 | Figure 2 | Figure 3 | Figure 4 |
This is the first image of Mars taken by the Context Camera on NASA's Mars
Reconnaissance Orbiter. The spacecraft began orbiting the red planet on
March 10, 2006. During its 10th close approach to Mars, on March 24, it
turned its cameras to view the planet's surface. Although the images
acquired were about 10 times lower in resolution than will ultimately be
obtained when the spacecraft has finished reshaping its orbit for the
mission's primary science phase, these test images provide important
confirmation of the performance of the cameras and the spacecraft.
This first image by the Context Camera includes some chaotic terrain at
the east end of Mars' Valles Marineris, seen along the top (northern) edge
of the image. The image has a scale of about 87 meters (285 feet) per
pixel, which is 14.5 times lower resolution than will be acquired during
the primary science phase. Typical images from the Context Camera acquired
during that phase of the mission will have a resolution of 6 meters (20
feet) per pixel, and will cover an area about 30 kilometers (18.6 miles)
wide.
Note that, because these are initial, test images, there is some linear
striping in the images. This results from incomplete removal of
pixel-to-pixel variations in the Context Camera detector by the present
calibration software. One use of the test imaging is an opportunity to
fine-tune the calibrations before the primary science phase begins.
Figure 1 is a comparison of a wide-angle, red-filter image from the Mars
Orbiter Camera on NASA's Mars Global Surveyor (left) with the first Mars
image from the Context Camera. The image from the Mars Orbiter Camera was
taken the same day, but about 6.2 hours after the image from the Context
Camera, at a local solar time of 1:42 p.m. The Context Camera image was
taken at roughly 7:32 a.m., local solar time.
Figure 2 shows a color view cropped from a Mars Orbiter Camera daily global
map acquired on the same day as the first two Mars images by the Context
Camera. The map shows the planet as if every part could be imaged at some
time between 1 p.m. and 3 p.m., that is, with early afternoon
illumination. The cameras on Mars Reconnaissance Orbiter, conversely,
imaged the planet during morning hours. The Mars Orbiter Camera view was
obtained about four hours later in the day than the Context Camera data.
Inserted into the daily global map are two grayscale views from the
Context Camera. This shows that the Context Camera began imaging when it
was over the southernmost portion of the chaotic terrain at the east end
of the Valles Marineris. A second image was acquired several minutes
later, as Mars Reconnaissance Orbiter flew southward towards the west
side of the large Argyre impact basin. The tops of the two Context Camera
images were obtained about 13 minutes apart.
Figure 3 the second image obtained by the Context Camera, is much longer than the
first: 260 kilometers (162 miles) at its widest point and about 122
kilometers (76 miles) at its narrowest, some 1,590 kilometers (988 miles)
to the south. It covers an area of about 40,000 square kilometers (about
15,400 square miles). The change in width reflects a change in altitude
of the Mars Reconnaissance Orbiter as it descended southward toward the
orbit's closest point to the planet. The picture is shown here at
one-third its original scale because the file size is large.
Figure 4 contains the northernmost portion of the second Context Camera
image, reproduced at one-half its original scale (because of its large
file size). The white box outlines the location of the first image from
the orbiter's High Resolution Imaging Science Experiment (PIA08060). The
Context Camera image and the High Resolution Imaging Science Experiment
image were acquired simultaneously. As with the Context Camera, the first
image from the High Resolution Imaging Science Experiment was of a much
lower resolution than will be obtained during the primary science phase
of the Mars Reconnaissance Orbiter mission, owing to the higher altitude
during this test. This figure illustrates one of the key roles that
Context Camera will play during the mission -- acquiring context images
for the other science instruments aboard the Mars Reconnaissance Orbiter.