Douglas Isbell
Headquarters, Washington, DC                   August 9, 1999
(Phone:  202/358-1547)

Mary Hardin/Frank O'Donnell
Jet Propulsion Laboratory, Pasadena, CA
(Phone:  818/354-5011)

NOTE TO EDITORS:  N99-044

MARS: AN ACTIVE PLANET TODAY? BRIEFING SET FOR AUGUST 10

     The camera aboard NASA's Mars Global Surveyor mission has revealed 
surprising new aspects of cloud fronts, dust devils and sand dunes on 
the red planet with major implications for understanding how the weather 
on Mars varies from season to season and from year to year.

     New still images and related video products that are helping 
scientists study these dynamic features in greater detail than ever 
before will be the subject of a press briefing on Tuesday, Aug. 10.  The 
Space Science Update will be held at 1 p.m. EDT in the James E. Webb 
Auditorium at NASA Headquarters, 300 E St. SW, Washington, DC.

     Briefing presenters will include:

-  Dr. Michael Malin, principal investigator for the Mars Orbiter Camera 
instrument on Mars Global Surveyor, from Malin Space Science Systems, 
San Diego
-  Dr. Peter Thomas, a member of the Mars Global Surveyor camera team 
from Cornell University, Ithaca, NY
-  Dr. Jim Zimbelman, planetary geologist in the Center for Earth and 
Planetary Studies at the Smithsonian Institution's Air & Space Museum, 
Washington, DC
-  Moderator Dr. Michael Meyer, Mars Surveyor 2001 program scientist in 
the Office of Space Science at NASA Headquarters

     Mars Global Surveyor carries five science instruments designed to 
generate a complete global portrait of Mars and its seasonal changes 
during a full Martian year, the equivalent of two Earth years.  The 
spacecraft entered its primary circular mapping orbit in February, and 
is just beginning its second full Martian year in orbit around the red 
planet.  

     Global Surveyor is the first mission in a long-term program of Mars 
exploration known as the Mars Surveyor Program, which is managed by the 
Jet Propulsion Laboratory (JPL), Pasadena, CA, for NASA's Office of 
Space Science, Washington, DC.  JPL's industrial partner is Lockheed 
Martin Astronautics, Denver, CO, which developed and operates the Global 
Surveyor spacecraft.  JPL is a division of the California Institute of 
Technology, Pasadena, CA.

     The briefing will be carried live on NASA Television, which is 
available on transponder 9C of the GE-2 satellite at 85 degrees West 
longitude, vertical polarization, frequency 3880 MHz, audio of 6.8 MHz.  
Two-way question and answer capability will be available for news media 
at NASA centers.

                                -end-