About 1000 Viking Orbiter red- and violet-filter images have been processed to provide global color coverage of Mars at a scale of 1 km/pixel. Individual image frames acquired during a single spacecraft revolution were first processed through radiometric calibration, cosmetic cleanup, geometric control, reprojection, and mosaicing. We have produced a total of 57 “single-rev” mosaics. All of the mosaics are geometrically tied to the Mars Digital Image Mosaic, a black-and-white base map with a scale of 231 m/pixel. We selected a subset of single-rev mosaics that provide the best global coverage (least atmospheric obscuration and seasonal frost); photometric normalization was applied to remove atmospheric effects and normalize the variations in illumination and viewing angles. Finally, these normalized mosaics were combined into global mosaics. Global coverage is about 98% complete in the red-filter mosaic and 95% complete in the violet-filter mosaic. Gaps were filled by interpolation. A green-filter image was synthesized from an average of the red and violet filter data to complete a 3-color set. The Viking Orbiters acquired actual green-filter images for only about half of the Martian surface. The final mosaic has been reprojected into several map projections. The orthographic view shown here is centered at 20 degrees latitude and 60 degrees longitude. The orthographic view is most like the view seen by a distant observer looking through a telescope. The color balance selected for these images was designed to be close to natural color for the bright reddish regions such as Tharsis and Arabia, but the data have been “stretched” such that the relatively dark regions appear darker and less reddish that their natural appearance. This stretching allows us to better see the color and brightness variations on Mars, which are related to the composition or physical structure of the surface materials, which include volcanic lava flows, wind- and water-deposited sedimentary rocks, and (at the poles) ice caps. The north polar cap is visible in this projection at the top of the image, the great equatorial canyon system (Valles Marineris) below center, and four huge Tharsis volcanoes (and several smaller ones) at left. Also note heavy impact cratering of the highlands (bottom and right portions of this mosaic) and the younger, less heavily cratered terrains elsewhere.
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NASA Seeks Industry Ideas for an Advanced Mars Satellite
NASA is soliciting ideas from U.S. industry for designs of a Mars orbiter for potential launch in the 2020s. The satellite would provide advanced communications and imaging, as well as robotic science exploration, in support of NASA’s Journey to Mars.
The orbiter would substantially increase bandwidth communications and maintain high-resolution imaging capability. It also may use experimental cutting-edge technologies, such as high-power solar electric propulsion or an optical communications package, which could greatly improve transmission speed and capacity over radio frequency systems.
Under the direction of NASA’s Mars Exploration Program, the agency’s Jet Propulsion Laboratory in Pasadena, California, is conducting pre-formulation planning for this possible orbiter mission. Pre-formulation plans include the procurement of industry studies for a solar-powered orbiting spacecraft. This effort seeks to take advantage of industry capabilities to improve deep space, solar electric propulsion-enabled orbiters to accommodate scientific instruments, demonstrate capability for rendezvous and capture, and advance telecommunications capabilities.
“Our success in exploring Mars, to unravel the mysteries of the Red Planet, depends on having high bandwidth communication with Earth and overhead imaging,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate in Washington. “Currently, we depend on our orbiting science missions to perform dual service in making measurements and acting as communication relays, but we can’t depend on them to last forever. This new orbiter will use cutting-edge technology to revitalize our ability to continue to explore Mars and support transformative science, including a potential sample return mission in the future.”
JPL plans to award concept study subcontracts of $400,000 per subcontract in June. The concept studies for the spacecraft will be completed over a four-month period.
In response to an earlier request from NASA, the Mars Exploration Program formed an analysis group that proposed, in a 2015 report, possible science objectives for a Mars orbiter capable of replenishing and advancing the telecommunications and reconnaissance resources available at Mars.
NASA is studying how to implement this mission concept in concert with its international partners to the greatest extent possible. Historically, there have been significant international contributions to NASA Mars missions that include the Curiosity rover, Mars Reconnaissance Orbiter spacecraft and the Mars Atmosphere and Volatile Evolution Mission orbiter, both currently orbiting the Red Planet. The agency will seek such partnerships for this potential future orbiter mission, as well.
NASA is on an ambitious journey to Mars that includes sending humans to the Red Planet, and that work remains on track. Robotic spacecraft are leading the way for the Mars Exploration Program, with current missions, in addition to the planned launch of the Insight lander in 2018, and the design and build of the Mars 2020 rover.
source : NASA – Jet Propulsion Laboratory – California Institute of Technology