Douglas Isbell 
Headquarters, Washington, DC                  September 11, 1998
(Phone:  202/358-1547)

RELEASE:  98-165


     Small spacecraft to study the vast region between our Sun and 
nearby stars and the interaction of Earth's radiation belts with 
the solar wind have been selected as the first missions in NASA's 
University-class Explorers (UNEX) program. 

     "This selection is another step in NASA's efforts to provide 
increased autonomy and responsibility to the university community 
in the pursuit of new scientific knowledge," said Dr. Wesley T. 
Huntress Jr., Associate Administrator for NASA's Office of Space 

     The Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) 
spacecraft will use an extreme ultraviolet spectrograph during its 
one-year mission to study the "Local Bubble," a tenuous cloud of 
hot gas surrounding our Solar System that extends about 300 light-
years from the Sun.  Scientists believe that the million-degree 
gas in this region is generated by supernovae and stellar winds 
from hot stars, but want to better understand the origins and 
cooling of this gas, and apply knowledge of these processes to the 
study of other galaxies beyond our Milky Way. 

     The Principal Investigator for CHIPS is Dr. Mark Hurwitz of 
the University of California, Berkeley.  The Earth-orbiting 
mission will cost $9.8 million, including launch, and will be 
launched aboard a commercial Final Analysis Inc. Satellite 
(FAISAT) as a secondary payload on a Russian Cosmos rocket in mid-

     The second mission, the Inner Magnetosphere Explorer (IMEX), 
will study the response of Earth's Van Allen radiation belts to 
variations in the solar wind.  The energetic charged particles 
(mainly protons and electrons) that comprise Earth's radiation 
belts are potentially hazardous to both astronauts and satellite 
systems.  IMEX will be launched into a 217-mile by 21,748-mile 
(350-kilometer by 35,000-kilometer) elliptical orbit around Earth 
with instruments to measure the populations of energetic particles 
and related magnetic and electric fields throughout Earth's 
radiation belts on a regular basis. 

     Together with other NASA satellites, data obtained with IMEX 
during these 10-hour sweeps should lead to significant 
improvements in our ability to predict hazardous conditions in 
Earth's radiation belts and our understanding of the underlying 
physical processes that connect the solar wind with the state of 
the Van Allen belts, especially during the upcoming maximum in the 
solar cycle.  The Principal Investigator for IMEX is 
Dr. John Wygant of the University of Minnesota in Minneapolis.  
IMEX will cost $13 million and is planned to be launched as a 
secondary mission on an Air Force Titan IV rocket in June 2001. 

     The UNEX Program is designed to provide frequent flight 
opportunities for highly focused and relatively inexpensive 
science missions whose total cost to NASA is limited to $13 
million.  The program is managed by NASA's Goddard Space Flight 
Center, Greenbelt, MD, for the Office of Space Science, 
Washington, DC. 

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