As part of
its quest to find Earth-sized planets around stars and look
for telltale chemical signatures of life, NASA has chosen
two mission architecture concepts for further study and
technology development.

The two architectures are being explored for the
Terrestrial Planet Finder mission. Each would use a
different means to achieve the same goal – to block the
light from a parent star in order to see its much smaller,
dimmer planets. That technology challenge has been likened
to finding a firefly near the beam of a brilliant
searchlight from far away. Additional goals of the mission
would include characterizing the surfaces and atmospheres of
newfound planets, and looking for the chemical signatures of

The two candidate architectures are:

— Infrared Interferometer: Multiple small telescopes on
a fixed structure or on separated spacecraft flying in
precision formation would simulate a much larger, very
powerful telescope. The interferometer would utilize a
technique called nulling to reduce the starlight by a factor
of one million, thus enabling the detection of the very dim
infrared emission from the planets.

— Visible Light Coronagraph: A large optical telescope,
with a mirror three to fourNDOes bigger and at least 10
times more precise than the Hubble Space Telescope, would
collect starlight and the very dim reflected light from the
planets. The telescope would have special optics to reduce
the starlight by a factor of one billion, thus enabling
astronomers to detect the faint planets.

The Terrestrial Planet Finder project at NASA’s Jet
Propulsion Laboratory, Pasadena, Calif., selected the two
candidates based on results from four industrial-academic
teams that conducted a 2- 1/2 year study of more than 60
possible designs. The two architectures were determined to
be sufficiently realistic to warrant further study and
technological development in support of a launch of
Terrestrial Planet Finder by the middle of the next decade.

NASA and JPL will issue calls for proposals seeking input
on the development and demonstration of technologies to
implement the two architectures, and on scientific research
relevant to planet finding. It is anticipated that one of
the two architectures will be selected in 2005 or 2006 to be
implemented for the mission, which may include international

Terrestrial Planet Finder is part of NASA’s Origins
Program, a series of missions to study the formation of
galaxies, stars and planets, and to search for life. The
program seeks to answers the questions: Where did we come
from? Are we alone?

More information on the Terrestrial Planet Finder is
available at: .

More information on the Origins Program is available at: .

Additional information on JPL’s planet-finding missions is
available at: .

JPL manages the Terrestrial Planet Finder mission and the
Origins Program for NASA’s Office of Space Science,
Washington, D.C. JPL is a division of the California
Institute of Technology in Pasadena.