[escepticos] [ASTRO] Mars Global Surveyor To Attempt Imaging of 'Face' On Mars, Viking & Pathfinder Landing Sites

["Víctor R. Ruiz" <rvr@...>]

>MEDIA RELATIONS OFFICE
>JET PROPULSION LABORATORY
>CALIFORNIA INSTITUTE OF TECHNOLOGY
>NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
>PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
>http://www.jpl.nasa.gov
>
>Contact: Diane Ainsworth
>
>FOR IMMEDIATE RELEASE March 26, 1998
>
>MARS GLOBAL SURVEYOR TO ATTEMPT IMAGING OF FEATURES OF PUBLIC INTEREST
>
>NASA's Mars Global Surveyor spacecraft is about to begin a summer-long set
>of scientific observations of the red planet from an interim elliptical
>orbit, including several attempts to take images of features of public
>interest ranging from the Mars Pathfinder and Viking mission landing sites
>to the Cydonia region.
>
>The spacecraft will turn on its payload of science instruments on March 27,
>about 12 hours after it suspends "aerobraking," a technique that lowers the
>spacecraft's orbit by using atmospheric drag each time it passes close to
>the planet on each looping orbit. Aerobraking will resume in September and
>continue until March 1999, when the spacecraft will be in a final, circular
>orbit for its prime mapping mission.
>
>It will not be possible to predict on which orbit the spacecraft will pass
>closest to specific features on Mars until Global Surveyor has established a
>stable orbit and flight controllers are able to project its ground track.
>This process should be completed in the next few days. The exact time of
>observations and the schedule for the subsequent availability of photographs
>on the World Wide Web are expected to be announced early next week.
>
>"Global Surveyor will have three opportunities in the next month to see each
>of the sites, including the Cydonia region, location of the so-called 'Face
>on Mars,' " said Glenn E. Cunningham, Mars Global Surveyor project manager
>at NASA's Jet Propulsion Laboratory, Pasadena, CA. "The sites will be
>visible about once every eight days, and we'll have a 30- to- 50-percent
>chance of capturing images of the sites each time."
>
>Several factors limit the chances of obtaining images of specific features
>with the high-resolution mode of the camera on any one pass. These factors
>are related primarily to uncertainties both in the spacecraft's pointing and
>the knowledge of the spacecraft's ground track from its navigation data. In
>addition, current maps of Mars are derived from Viking data taken more than
>20 years ago. Data obtained by Global Surveyor's laser altimeter and camera
>during the last few months have indicated that our knowledge of specific
>locations on the surface is uncertain by 1 to 2 kilometers (0.6 to 1.2
>miles). As a result, the locations of the landing sites and specific
>features in the Cydonia region are not precisely known.
>
>In addition, the Mars Pathfinder and Viking landers are very small targets
>to image, even at the closest distance possible, because they are the
>smallest objects that the camera can see. The Cydonia features, on the other
>hand, are hundreds to thousands of times larger and the camera should be
>able to capture some of the features in that area.
>
>Global Surveyor's observations of the Viking and Pathfinder landing sites
>will provide scientists with important information from which to tie
>together surface observations and orbital measurements of the planet. Data
>from landing sites provide "ground truth" for observations of the planet
>made from space.
>
>As for the "Face on Mars" feature, "Most scientists believe that everything
>we've seen on Mars is of natural origin," said Dr. Carl Pilcher, acting
>science director for solar system exploration in NASA's Office of Space
>Science, Washington, DC. "However, we also believe it is appropriate to seek
>to resolve speculation about features in the Cydonia region by obtaining
>images when it is possible to do so."
>
>Information about Viking observations of the Cydonia region and a listing of
>those images are available on the World Wide Web at
>http://www.hq.nasa.gov/office/pao/facts/HTML/FS-016-HQ.html .
>
>New images of the landing sites and Cydonia region taken by Mars Global
>Surveyor will be available on JPL's Mars news site at:
>http://www.jpl.nasa.gov/marsnews and on the Global Surveyor home page at
>http://mars.jpl.nasa.gov . These sites will also carry detailed schedules of
>the imaging attempts once they have been determined. Images will also be
>available on NASA's Planetary Photojournal web site at
>http://photojournal.jpl.nasa.gov .
>
>So far in the aerobraking process, Global Surveyor's orbit has been reduced
>from an initial 45-hour duration to less than 12 hours. During the
>aerobraking hiatus, the spacecraft will be orbiting Mars about once every
>11.6 hours, passing about 106 miles (170 kilometers) above the surface at
>closest approach and about 11,100 miles (17,864 kilometers) at its farthest
>distance from the planet. The pause in aerobraking allows the spacecraft to
>achieve a final orbit with lighting conditions that are optimal for science
>observations.
>
>Mars Global Surveyor is part of a sustained program of Mars exploration,
>managed by JPL for NASA's Office of Space Science, Washington, DC. Lockheed
>Martin Astronautics, Denver, CO, which built and operates the spacecraft, is
>JPL's industrial partner in the mission. Malin Space Science Systems, Inc.,
>San Diego, CA, built and operates the spacecraft camera. JPL is a division
>of the California Institute of Technology, Pasadena, CA.
>
>                          #####
>
>
>

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Víctor R. Ruiz                rvr en idecnet.com
   Agrupación Astronómica de Gran Canaria
  Sociedad de Meteoros y Cometas de España
info.astro  http://www.astrored.org/infoastro
http://ccdis.dis.ulpgc.es:8086/AAGC/aagc.html
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