Paula Cleggett-Haleim
Headquarters, Washington, D.C.                                                     
October 28, 1991
(Phone:  202/453-1547)

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

RELEASE:  91-177

LARGE SCALE MAPS OF VENUS TO BE RELEASED

Large-scale hemispheric maps of Venus will be released at a news 
conference at NASA Headquarters, Washington, D.C., at 1 p.m. EST, 
Tuesday, Oct. 29.  The maps were made from the radar data acquired 
by the Magellan spacecraft in its first, 8-month long, mapping 
cycle.  The processing of the "cycle 1" data sets, for both imagery 
and altimetry, was completed recently.

Magellan Project Scientist Dr. Steve Saunders, Jet Propulsion 
Laboratory, Pasadena, Calif., also will show a three-dimensional 
perspective video at the press briefing.  The video illustrates the 
fractured and rifted terrain of Venus.

Dr. John Wood, Smithsonian Astrophysical Observatory, one of the 
Magellan science team members who has studied rock weathering on 
Venus, will discuss the volcano Maat Mons, which he says may be of 
very recent origin.

"The Magellan test stereo data appear to be the best radar stereo 
data ever obtained by any program," Saunders said.  Saunders will 
discuss the images and release a new stereo image along with the 
video and other products.

Other members of the science team will present results of a radio 
occultation experiment that looked at the planet's atmosphere using 
the spacecraft's radio signal.  Saunders said the radio science 
data looks very "clean" and will provide information about the 
distribution of sulfuric acid vapor down to about 20.5 miles above 
the surface, much lower than previous spacecraft experiments have 
been able to measure.

Dr. Gordon Pettengill, Massachusetts Institute of Technology 
Principal Investigator for the radar experiment, will discuss 
completion of the global Venus altimetry and radiometry data sets 
from Magellan's first mapping cycle.

The news conference will be carried live on NASA Select Television.  
The Jet Propulsion Laboratory manages the Magellan Project for 
NASA's Office of Space Science and Applications.
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