Advanced Imaging

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Advanced Imaging Magazine

Updated: January 12th, 2011 10:01 AM CDT

Imaging in Space

Space shuttles and Mars missions require performance, sensitivity and ruggedness
Astronaut Garrett Reisman
© NASA
Astronaut Garrett Reisman, STS-124 mission specialist, looks over a checklist while holding a camera in the Destiny laboratory of the International Space Station while Space Shuttle Discovery is docked with the station. The astronaut is holding a Kodak DCS camera.
The Daily weather data for Mars is collected by the orbiter using the Mars Color Imager
© NASA
The Daily weather data for Mars is collected by the orbiter using the Mars Color Imager (MARCI). The data includes phenomena like dust devils, as seen in this image taken earlier this year.
The Mars Reconnaissance Orbiter
© NASA/JPL/Malin Space Science Systems
The Mars Reconnaissance Orbiter (MRO) Context Camera (CTX) is designed to obtain grayscale (black & white) images of Mars at 6 meters per pixel scale over a swath 30 kilometers wide.
terra sirenum crater on Mars
© NASA/JPL/Malin Space Science Systems
The largest numbers of gullies on Mars are on the walls of southern hemisphere craters. During southern winter, many of the gullied walls are in shadow. It has been known for many years from Mars Global Surveyor Mars Orbiter Camera images that frost forms on these shadowed slopes and that differences in the amount or nature of the frost deposits highlight the gully floors and deposits. CTX acquired this image of the terra sirenum crater where gullies were known to display frost during winter.
50-foot robotic arm
© Adimec
An Adimec camera and Kodak sensors are key components of the Orbiter Boom Sensor System (OBSS), an in-flight imaging system attached to the end of a 50-foot robotic arm that is used by shuttle astronauts to scan the underside of the orbiter for possible damage before landing. 
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By Barry Hochfelder

IN CONTEXT

The orbiter's Context Camera (CTX) is based on the Kodak KLI-5001 Image Sensor, a 5,000-pixel linear CCD device that scans the surface of the planet as the orbiter passes overhead. Providing a resolution of six meters per pixel (allowing features the size of a large pick-up truck to be detected), this camera now has mapped more than one-third of the planet's surface (that's more than one trillion data points), and is also being used to help evaluate potential landing sites for the 2009 Mars Science Laboratory rover mission, says Mike DeLuca, Marketing Manager, Imaging Sensor Solutions at Kodak.

From its 3 p.m. circular, polar orbit, the CTX will obtain grayscale (black-and-white) images of the Martian surface with a spatial resolution of about 6 meters (20 feet) per pixel over a swath that is about 30 kilometers (18.6 miles) wide. CTX is a Facility Instrument, operated by Malin Space Science Systems and the MRO MARCI science team.

As its name implies, CTX will provide context for images acquired by other instruments onboard the Mars Reconnaissance Orbiter, particularly the High Resolution Imaging Science Experiment (HiRISE) and the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). CTX provides black & white images of the planet's surface at six meters per pixel (enough to detect a large pickup truck) over a swath 30km wide, and is used to provide a context for high-resolution analysis of key locations of the planet.

The instrument consists of a 350mm focal length, 6º field of view, catadioptric Cassegrain (Maksutov-type) telescope that images onto a 5064 pixels-wide charge coupled device (CDD) line array. The CCD detects a broad band of visible light from 500 to 800 nanometers in wavelength. The instrument includes a 256MB DRAM buffer, so that it can acquire pictures that have downtrack lengths greater than 160 kilometers (99 miles). In other words, a typical CTX image can be as wide as 30km and as long as 160km, or more.

The MRO MARCI is the second such camera to be sent to Mars. The first was competively selected by NASA to fly on the Mars Climate Orbiter (MCO) in 1998. That spacecraft was lost during orbit insertion in September 1999. The MCO MARCI had two cameras—a wide-angle system to provide daily global views of the planet, and a medium-angle system to provide 40 meters per pixel views of selected areas to be examined for landing site studies. For the 2005 MRO mission, NASA decided only to re-fly the MARCI wide-angle system, and replace the 40 meters per pixel medium angle camera with the 6 meters per pixel Context Camera (CTX).



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