Mars Reconnaissance Orbiter: Earth-Moon Calibration Image

http://www.msss.com/mro/ctx/images/2.../12/index.html

Mars Reconnaissance Orbiter
Context Camera

Earth-Moon Calibration Image

MRO CTX Release No. CTX-00002, 12 September 2005


CTX-00002a: Earth and Moon

CTX calibration image showing Earth (saturated white, as expected) and
Moon.

NASA/JPL/MSSS

CTX-00002b: Simulated and Actual CTX Views of Moon
Three views of the Moon: from Clementine UVVIS Global Mosaic; a
simulated CTX view derived from the UVVIS mosaic; and the actual CTX
view (magnified).
NASA/JPL/Malin Space Science Systems

On Thursday, 8 September 2005, the Mars Reconnaissance Orbiter (MRO)
Context Camera (CTX) was powered on and the MRO spacecracft pointed the
camera at Earth and the Moon. This occurred at the same time that MRO's
HiRISE camera was also imaging the Moon (see: PIA08005
http://photojournal.jpl.nasa.gov/catalog/PIA08005 and PIA08002
http://photojournal.jpl.nasa.gov/catalog/PIA08002 for HiRISE's view).
The two objects, Earth and Moon, were about 10 million kilometers (~6
million miles) from the MRO spacecraft at the time the data were
obtained.

The purpose of this activity was to acquire calibration images. These
images were used to verify that the CTX camera focus and sensitivity
remained unchanged following the rigors of the launch environment and
upon initial exposure and operation in the cold vacuum of deep space.

The CTX took 5 images of Earth and the Moon and 5 images of stars in
the
vicinity of Omega Centauri. The first image, above, shows Earth and the
Moon. Earth is overexposed because the exposure was set for the
brightness of the Moon (which is only about 1/5th as bright as Earth).
In other words, the CTX team expected and planned that the image of
Earth would be saturated white. The left side of the second image shows
a computer graphic representation of the portion of the Moon visible to
CTX, using as a base map the Clementine UVVIS mosaic assembled by the
U.
S. Geologcial Survey. The middle of the
second figure shows a simulation of the CTX picture derived from the
Clementine mosaic, while the right side of the figure shows the actual
CTX image, greatly magnified.

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Malin Space Science Systems built two cameras on the Mars
Reconnaissance
Orbiter the Context Camera (CTX) and the Mars Color Imager (MARCI).
MSSS
operates both cameras from its facilities in San Diego, California. The
Jet Propulsion Laboratory's operates the MRO spacecraft with its
industrial partner, Lockheed Martin Space Systems Company, from
facilities in Pasadena, California and Denver, Colorado.