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Special Handling Required For Samples From Some Space Objects

The Executive Summary of the report is available at
http://www.nap.edu/readingroom/enter2.cgi?0309061369.html .


National Academy of Sciences

Contacts: Cheryl Greenhouse, Media Relations Officer
Sean McLaughlin, Media Relations Assistant
(202) 334-2138; e-mail 


Special Handling Required for Samples From Some Space Objects

NASA is planning several missions in the next decade to collect
samples from a variety of small solar system bodies and planetary
satellites. At the request of the agency, a task force of the National
Research Council surveyed the potential for microscopic life existing
on moons, asteroids, comets, and cosmic dust, and determined that a
few cases may pose enough risk of contaminating Earth to require
special handling procedures when the samples are brought home.

To establish its risk criteria, the task force first looked at the
range of conditions under which life can propagate. These conditions
include the presence of water and organic compounds, availability of
energy sources, suitable temperatures, and protection from radiation.
The group also considered conditions under which life can be dormant.
And, they considered the possibility that materials containing life
forms could have been transported to objects from elsewhere in the
solar system -- for example, on a meteorite.

Although the chances of encountering life forms are extremely low,
samples meeting the task force's criteria would require strict
containment procedures modeled on those recommended for samples
brought back from Mars, as outlined in a 1997 Research Council report.
These procedures include quarantine, screening, and otherwise treating
the materials as if they were biohazards until proved safe.

Of the space objects considered in the report, two of Jupiter's moons
-- Europa and Ganymede -- offer the greatest potential of harboring
microscopic life. Europa is the prime candidate among the objects
studied for the possibility of past or present life based on evidence
from the Voyager and Galileo space probes of an ocean beneath the
moon's icy crust. Because Ganymede may once have had an ocean as well,
caution in handling samples taken from there is also warranted.
Sufficient temperatures for the existence of life and protection from
radiation may also be present given the moons' positions orbiting

In addition, samples from certain types of asteroids -- the P- and
D-types found in the outer parts of the asteroid belt between Mars and
Jupiter -- merit strict procedures as a precaution because so little
is known about their origin and composition. The task force
recommended that dust particles collected near Europa, Ganymede, and
these asteroids be approached with the same caution.

The report notes cases in which no special handling or containment
procedures are necessary because these objects have been determined to
be lifeless or because their conditions preclude the presence of life.
These objects include the Earth's moon, new comets, and cosmic dust
exposed to sterilizing radiation in space.

However, the report calls for scrutiny in any case where a lack of
complete data cannot eliminate all risks. To reduce uncertainties in
these cases, the task force recommended creating a database that
charts the capacity of earthly microbes to survive extreme
temperatures and radiation similar to those found in space. Such data
could help determine the levels needed to sterilize samples.

The study was funded by NASA. The National Research Council is the
principal operating agency of the National Academy of Sciences and the
National Academy of Engineering. It is a private, non-profit
institution that provides science and technology advice under a
congressional charter. A task force roster follows.

Copies of Evaluating the Biological Potential in Returned Samples from
Planetary Satellites and Small Solar System Bodies: Framework for
Decision Making will be available in August from the National Academy
Press for an estimated $40.00 (prepaid) plus shipping charges of $4.00
for the first copy and $.50 for each additional copy; tel. (202)
334-3313 or 1-800-624-6242. Reporters may obtain a pre-publication
copy from the Office of News and Public Information (contacts listed

Commission on Physical Sciences, Mathematics, and Applications
Space Studies Board

Task Group on Sample Return from Small Solar System Bodies

Leslie Orgel*(chair)
Senior Fellow and Research Professor
Salk Institute for Biological Studies
San Diego

Michael A'Hearn
Professor of Astronomy
Computer and Space Science
University of Maryland
College Park

Jeffrey Bada
Professor of Marine Chemistry, and
Director of NSCORT/Exobiology Program
Scripps Institution of Oceanography
University of California, San Diego
La Jolla

John Baross
Professor of Marine Biology
School of Oceanography
University of Washington

Clark Chapman
Southwest Research Institute
Boulder, Colo.

Michael Drake
Director of the Lunar and Planetary Laboratory, and
Head of the Department of Planetary Sciences
University of Arizona

John Kerridge
Research Cosmochemist
Department of Chemistry
University of California
San Diego

Margaret S. Race
Principal Investigator
SETI Institute
Mountain View, Calif.

Mitchell Sogin
Director, Bay Paul Center for Comparative
Molecular Biology and Evolution
Marine Biological Laboratory
Woods Hole, Mass.

Steven Squyres
Professor, Department of Astronomy
Center for Radiophysics and Space Research
Cornell University
Ithaca, N.Y.


Joseph L. Zelibor Jr.
Study Director

(*) Member, National Academy of Sciences

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