Brian Dunbar
Headquarters, Washington, D.C.                                                                     
May 24, 1991
(Phone:  202/453-1547)

Jerry Berg
Marshall Space Flight Center, Huntsville, Ala.
(Phone:  205/544-6540)


RELEASE:  91-77

ARTIFICIAL AURORA EXPERIMENT RESULTS TO BE PRESENTED


   Scientists, whose experiments produced brightly colored 
clouds in night skies over the Americas and triggered 
artificial Earth auroras thousands of miles away, will discuss 
their findings at a May 28 session of the American Geophysical 
Union's spring meeting in Baltimore, Md. 

   Dr. David Reasoner, CRRES project scientist at NASA's 
Marshall Space Flight Center, Huntsville, Ala., will chair the 
session at which 12 scientific papers will be presented. 

   The experiments were conducted during January and February 
of this year with the Combined Release and Radiation Effects 
Satellite (CRRES).  This joint NASA-Air Force effort studied 
the Earth's magnetic fields and the effects of space radiation 
on spacecraft components.

    NASA, Air Force and participating scientists successfully 
completed eight experiments involving releases of small 
amounts of barium and lithium from the satellite.  The 
releases allowed scientists to study the response of the space 
environment to the injection of artificial clouds of charged 
particles. 

   The barium releases were done at varying altitudes to test 
the response at low altitudes, where the Earth's magnetic 
field has strong control, and at high altitudes, where the 
magnetic field is weak. 

   The lithium releases used lithium ions as "tracers" which 
could be tracked by detectors on CRRES and other satellites, 
to reveal information about the complex processes which 
transport charged particles. 

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   Releases of  barium and lithium were done at points over 
the equator that were connected by magnetic field lines to the 
regions of aurora borealis activity over northern Canada. 

   "Two of the barium releases produced noticeable 
enhancements in auroral activity and significant changes in 
the high energy charged particles around the satellite," 
Reasoner said.  "So, these injections of artificial plasma 
clouds, involving about 25 pounds of barium, produced 
measurable effects over the very large dimensions -- tens of 
thousands of miles -- of the Earth's magnetic field regions." 

   The auroral effects were detected with high-sensitivity 
cameras carried aboard two specially modified U.S. Air Force 
KC-135 aircraft.  In addition, observations of the CRRES 
experiments were made with optical instruments in the United 
States, the Caribbean and South America. 

   The public was able to observe the releases as well.  NASA 
received many reports of visual sightings of the colored 
clouds, as well as photographs made by amateur photographers.  

   The next campaign in the program will be a series of 
releases over the Caribbean in July and August.  Releases of 
barium from both the satellite and from sounding rockets will 
be used in a series of experiments designed to investigate the 
effects of artificial ion clouds on the electrically 
conducting ionosphere layers and to trace the geometry of 
electric and magnetic fields.  These releases may be visible 
from most areas of the Caribbean.

   CRRES is managed by MSFC for NASA's Office of Space Science 
and Applications, Headquarters, Washington, D.C.

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