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Photos of Phobos: Standards Help Capture High Resolution Images of Martian Moon

New York, Apr 10, 2008

The High Resolution Imaging Science Experiment (HiRISE) on board the Mars Reconnaissance Orbiter has captured some of the highest quality images of Phobos, one of Mars' two moons.

Largely thought to be a captured asteroid, Phobos has been proposed as a potential initial landing site for the first manned mission to Mars. Thanks to a number of information technology and image coding standards, HiRISE can provide ultra high-resolution images for additional study and discussion by the scientists reviewing current and planned missions to the red planet.

HiRISE’s powerful 0.5 meter aperture telescope produces very large images that often exceed 30,000 by 10,000 pixels. A standard developed by Joint Technical Committee 1 (JTC 1) of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) provides a solution for the storage and distribution of these large data files. ISO/IEC 15444-1:2004, Information technology - JPEG 2000 image coding system: Core coding system, defines a set of methods to compress source data and to reconstruct compressed image files without a loss in image quality. According to the HiRISE Software Interface Specification, some of the specific advantages of the JP2 file type include excellent compression performance, multiple resolution levels from a single image data set, lossless compression, and selective image area access.

The American National Standards Institute (ANSI) serves as Secretariat of JTC 1, and the InterNational Committee for Information Technology Standards (INCITS) is the ANSI-accredited U.S. TAG Administrator.

Another JTC 1 standard helps HiRISE to communicate its JP2 file contents to various remote clients such as the National Aeronautics and Space Administration (NASA) and its Jet Propulsion Laboratory (JPL). ISO/IEC 15444-9:2005, Information technology - JPEG 2000 image coding system: Interactivity tools, APIs and protocols, defines the JPEG 2000 Interactive Protocol (JPIP), a sophisticated tool that takes advantage of the incremental rendering of the JP2 image data and results in significantly reduced data network bandwidth requirements. As a result, JPIP users here on Earth can pan and zoom throughout the complete HiRISE image without having to transmit and render the entire file.

HiRISE data and imagery is not just for use by NASA and JPL scientists; the information is freely available for anyone to download and process. Interested parties need only download the Integrated Software for Imagers and Spectrometers (ISIS), a free program provided by the U.S. Geological Survey that allows users to manipulate imagery collected by current and past NASA planetary missions.

Even amateur photographers can appreciate that photographing a moving object is a difficult task. In capturing images of Phobos, HiRISE needs to account for the moon’s motion as well as the velocity of its host, the Mars Reconnaissance Orbiter. HiRISE must also be able to stitch together the data coming from separate filters that capture red, blue-green, and near-infrared light. The ability to uniformly initiate, coordinate, and record the timing of spacecraft activities is key.

For any image observation event, HiRISE relies upon Coordinated Universal Time (UTC) parameters as defined in ISO 8601:2004, Data elements and interchange formats - Information interchange - Representation of dates and times. The Data Interchange Standards Association, Inc. is the ANSI-accredited U.S. TAG Administrator to TC 154, the ISO technical committee responsible for developing the standard.

As HiRISE continues its Martian orbit, NASA welcomes public comments on the next imaging targets. To help scientists determine where to next turn their telescope, visit the HiRISE Image Targeting Challenge website and submit a suggestion.

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