A mission proposal from NASA Ames Research Center to measure the
pre-biological chemical building blocks of life in deep space has
been selected as a next-mission candidate under NASA’S Explorer
Program — a roster of low-cost, focused next-generation spacecraft.

The Astrobiology Explorer, known as ABE, has a hydrogen ice-chilled
telescope that will search for interstellar organic compounds, such
as carbon-containing ices, dust and molecules, throughout the
universe. If chosen, the $180 million mission will fly as early as
2007. The ABE spacecraft will be put into an orbit around the sun,
gradually drifting 14 million miles away from Earth during its
18-month mission lifetime.

“This is the next step,” said Ames principal investigator Dr. Scott
Sandford. “We need an infrared telescope in space because we can’t
measure signals at these wavelengths using even the largest
ground-based telescopes.”

The ABE telescope must be chilled and put into space in order to
detect the very weak signals it seeks, which would otherwise be lost
in the flood of infrared radiation produced by the Earth’s own
warmth. “It’s as if we were trying to detect the light from a candle
that is held in front of a searchlight,” Sandford added. “Chilling
the telescope and putting it in space is like turning off the
searchlight.”

The telescope and its instruments will measure light at wavelengths
in the infrared spectrum, which are wavelengths about 10 times longer
than what the human eye can see, and that we experience as heat.

ABE’s primary goal is to understand the molecular chemistry that
occurs in space, and to identify the molecules that are found in
different space environments. ABE observations also will provide new
insights into the physical nature of young stars, comets, galaxies
and other objects in the universe.

ABE’s science team will look for the spectral signatures of complex
organic molecules and the simpler molecules from which they are
formed, such as water, ammonia and methanol. In recent laboratory
simulations of cold, space-like conditions, Sandford and other Ames
scientists found that organic molecules, including those necessary
for life, such as ketones and complex hydrocarbons, can be produced
in deep interstellar space.

One advantage ABE will have over previous infrared space
observatories, the researchers say, is its large, sensitive infrared
light detectors. These Ames-developed devices will allow researchers
to collect millions of pixels of information at once, much more than
previously.

“ABE will have three instruments called spectrometers, which will
slice up the light collected by the telescope,” said Ames’ Dr. Tom
Greene, ABE’s mission architect. “The detectors in these
spectrometers will sense the unique infrared signatures of many
atoms, molecules and dust grains.”

Sylvia Cox and other Ames personnel will serve as members of the ABE team.
The team will partner with Ball Aerospace and Technologies Corp.,
which will build the instrument and spacecraft. A group of 18
scientists from Ames, as well as other U.S. and international
institutes, also will work on ABE.

NASA will select two of the Explorer mission proposals by early 2003 for full
development as Medium-class Explorer flights. The Explorer program is
managed by NASA’s Goddard Space Flight Center, Greenbelt, Md., for
the Office of Space Science, Washington.

More information about ABE is available at:

http://www.astrochem.org/abe.html

More information about the Explorer program and the other selected
proposals is available at:

http://fpd.gsfc.nasa.gov/410/index.html