Donald L. Savage
Headquarters, Washington, D.C.                                                          
May 8, 1992
(Phone:  202/453-8400)


RELEASE:  92-63

NASA ANNOUNCES PLANS FOR SMALL PLANETARY MISSIONS


     NASA today delivered a report to the U.S. Senate outlining a 
shift in emphasis towards smaller, lower cost and more frequent 
planetary missions.  The Small Planetary Mission Plan, which was 
requested by the Senate Committee on Appropriations, Subcommittee 
on VA, HUD and Independent Agencies chaired by Sen. Barbara 
Mikulski (D-Md.), describes two proposed missions that NASA has 
selected for preliminary studies leading to launches in 1996 and 
1998.

     The two missions, part of the Discovery program, are the Mars 
Environmental Survey (MESUR) Pathfinder, planned for launch in 
1996, and the Near Earth Asteroid Rendezvous (NEAR), planned for a 
1998 launch.  Phase A studies of the MESUR Pathfinder mission have 
been awarded to NASA's Jet Propulsion Laboratory, Pasadena, Calif. 
(JPL).  The Applied Physics Laboratory of Johns Hopkins 
University, Baltimore, Md. (APL), has been awarded Phase A studies 
of the NEAR mission.

     "We're very excited about this plan," said Dr. Wesley T. 
Huntress, Jr., Director of NASA's Solar System Exploration 
Division.  "It will enable more opportunities for planetary 
exploration without a large budget impact.  It will allow us to 
more effectively take advantage of emerging technology and to 
quickly - and relatively cheaply - undertake new missions of 
discovery.  A significant benefit will be increased student 
involvement because the shorter project time-frames fit nicely 
with most academic degree programs."

     According to the report, the plan emphasizes a recent change 
in the character of NASA's Solar System Exploration Division's 
programs.  Most planetary missions of the past 2 decades have 
involved relatively large spacecraft with broad science goals.  
There have been only a few such missions per decade.  The new, 
less expensive projects can be launched more often, affording 
timely new opportunities to many investigators and institutions.  
They also can fill in gaps in the planetary exploration program 
and revitalize educational interest in planetary science.

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     Small planetary missions, described in the report as the 
centerpiece of NASA's new planetary programs for the 1990's, are 
designed to proceed from definition to flight in less than 3 
years, combining well-defined objectives, proven instruments and 
flight systems, strict cost limits and acceptance of a greater 
level of risk.  Most will be implemented by teams including 
substantial academic representation.

     The Discovery missions will be modeled on existing Explorer 
and Earth Probe programs, with each mission costing no more than 
$150 million.  The first Discovery mission, MESUR Pathfinder, is 
envisioned as a technical demonstration and validation flight for 
the MESUR program, scheduled to begin in 1999.  The MESUR program 
calls for building a network of about 16 small automated surface 
stations widely scattered around Mars to study the planet's 
internal structure, meteorology and local surface properties.

     NASA is studying the possibility of including a prototype of 
a Mars micro-rover on the MESUR Pathfinder lander.  The 
micro-rover, currently under joint development by the Solar System 
Exploration Division and NASA's Office of Aeronautics and Space 
Technology, would carry a camera and one or two additional 
scientific instruments.  The lander also may include instruments 
provided by NASA's Office of Exploration to search for subsurface 
ice and to measure soil toxicity.

     A second concept under study, NEAR, would spend up to a year 
station-keeping with a near-Earth asteroid.  The NEAR spacecraft, 
probably carrying only three instruments, would assess the 
asteroid's mass, size, density and spin rate, map its surface 
topography and composition, determine its internal properties and 
study its interaction with the interplanetary environment.

     Other candidate Discovery missions listed in the report 
include a Venus atmospheric probe, Earth-orbiting planetary 
telescopes, multiple asteroid/comet flybys and comet 
reconnaissance missions, a Mars orbiter to study the planet's 
upper atmosphere and missions to Mars' moons.

     Also included in the report to the Senate is the first phase 
of a program called Toward Other Planetary Systems (TOPS-O), 
consisting of ground-based observations to search for, identify 
and examine Jupiter-sized planets around other stars within 50 
light-years of Earth.  The TOPS-O plan includes development of a 
second 10-meter telescope at the Keck Observatory in Hawaii and 
enhanced instrumentation.

   The Discovery and TOPS programs are managed by the Solar System 
Exploration Division of the Office of Space Science and 
Applications, at NASA Headquarters, Washington, D.C.

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