Paula Cleggett-Haleim
Headquarters, Washington, D.C.                        May 29, 
1991
(Phone:  202/453-1549)

Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone:  818-354-5011)
 

RELEASE:  91-83

MAGELLAN MAPPING OF VENUS RESULTS REPORTED


   Magellan Project scientists today presented the results of 
the first 243-day radar mapping cycle of Venus as the 
spacecraft continued in a second cycle of exploring the 
cloud-shrouded surface of Earth's nearest planetary neighbor. 

   Dr. Stephen Saunders, Project Scientist, gave a summary of 
findings during the first cycle and compared radar images from 
the first two orbits last August when the radar instrument was 
being tested with new data covering the same surface area.  
Saunders reviewed global features, emphasizing wind streaks, 
large features called coronas and the continent-sized upland, 
Aphrodite Terra. 

   Dr. James Head, a Brown University member of the science 
team, discussed volcanic features and global distribution of 
volcanoes and described the search for surface changes during 
the second mapping cycle. 

    Dr. Gordon Pettengill, Massachusetts Institute of 
Technology Principal Investigator of the radar science group, 
released new altimetry and radiometry results with emphasis on 
western Aphrodite Terra and the peculiar characteristics of 
festoon -- looped or curved -- lava flows. 

    New radar images were released, along with a new video 
creating a simulated flight over a three-dimensional Venus 
surface.  The tape shows a large area of distinctive impact 
craters and a closeup of strange volcanoes called "pancake 
domes." 


                           - more -
                            - 2 -


   The first mapping cycle, begun last Sept. 15, imaged 84 
percent of the planet.  The cycle ended May 15 and the second 
cycle, to map the remainder of the surface, began immediately. 

   The spacecraft's orbit was trimmed on May 17 to enhance its 
altimetry coverage of Venus.  The altimetry instrument 
measures the heights of features on the surface. 

    Saunders and the other Magellan scientists addressed a 
news conference at NASA Headquarters, Washington, D.C. 

                           - end -