[meteorite-list] NASA Study Finds New Kind of Organics in Stardust Mission

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 14 Dec 2006 13:32:35 -0800 (PST)
Message-ID: <200612142132.NAA11714_at_zagami.jpl.nasa.gov>

http://stardust.jpl.nasa.gov/news/news108.html

NASA Study Finds New Kind of Organics in Stardust Mission
December 14, 2006

A team of scientists found a new class of organics in
comet dust captured from comet Wild 2 in 2004 by NASA's
Stardust spacecraft.

The discovery is described in a technical paper,
"Organics Captured from Comet Wild 2 by the Stardust
Spacecraft," in the Dec. 15 issue of Science Express,
the online edition of the journal Science.

In January 2004, the Stardust spacecraft flew through
comet dust and captured specks of it in a very light,
low-density substance called aerogel. Stardust's return
capsule parachuted to the Utah Test and Training Range
on Jan. 15, 2006, after a seven-year mission. The
science canister containing the comet particles and
interstellar dust particles arrived at Johnson Space
Center on Jan. 17. From there, the cometary samples
have been processed and distributed to about 150
scientists worldwide who are using a variety of
techniques to determine the properties of the
cometary grains.

"A portion of the organic material in the samples is
unlike anything seen before in extraterrestrial
materials," said Scott Sandford, the study's lead
author and a scientist from NASA's Ames Research
Center in California's Silicon Valley. "Capturing
the particles in aerogel was a little bit like
collecting BBs by shooting them into Styrofoam."

The comet organics collected by the Stardust spacecraft
are more "primitive" than those seen in meteorites and
may have formed by processes in nebulae, either in space
clouds between the stars, or in the disk-shaped cloud of
gas and dust from which our solar system formed, the
study's authors found.

"Comets are a major source of the water and carbon on
the moon," said S. Pete Worden, NASA Ames director.
"Therefore, understanding comets will help scientists
learn what natural resources to search for on our
nearest neighbor in space -- resources that will aid
astronauts in exploration beyond Earth," Worden
explained.

The study's scientists used many highly sophisticated,
state-of-the-art techniques to analyze the Stardust
samples.

Several of the analyses indicated that the samples
contain polycyclic aromatic hydrocarbons (PAHs),
scientists said. PAHs are molecules made of carbon
and hydrogen that are common in interstellar space -
and in barbeque grill soot.

Certain PAHs chemical varieties also contain oxygen
and nitrogen. Some scientists believe that these PAHs
variants exist in interstellar space as well. They
are of interest to astrobiologists because these kinds
of compounds play important roles in terrestrial
biochemistry, according to Sandford.

"Our studies of the comet dust show that the organics
are very rich in oxygen and nitrogen," Sandford said.
"The data are not incompatible with some of it being
in the PAHs, but we still have a lot to learn in this
area."

Although some of the other organics captured by the
Stardust spacecraft look somewhat similar to the
fairly stable organics found in meteorites, Sandford
noted that many of the organic compounds appear to be
very volatile. One sample even showed an abundance of
material containing alcohols.

Many scientists believe that comets are largely made
of the original material from which our solar system
formed and could contain pre-solar system, interstellar
grains. According to scientists, continued analysis of
these celestial specks may well yield important insights
into the evolution of the sun, its planets and possibly,
even the origin of life.

"I anticipate that people will be asking for and working
on these samples for decades to come," said Sandford.
"What we report in the papers that appear this week is
just the beginning of what we will learn from these
samples. One of the advantages of returned samples is
that they are available for study into the future, a
gift that keeps on giving."

The organics paper is one of seven in the journal Science
reporting the findings of the preliminary examination
team that made the initial study of the cometary samples.

The Jet Propulsion Laboratory, Pasadena, Calif., manages
the Stardust mission for NASA's Science Mission
Directorate, Washington. Dr. Peter Tsou of JPL is
deputy principal investigator and is a co-author of the
paper.

For more information about Stardust studies and other
mission information, visit:

http://stardust.jpl.nasa.gov/ .

JPL Media Contact for Stardust:
DC Agle
Phone: 818-393-9011
agle at jpl.nasa.gov
Received on Thu 14 Dec 2006 04:32:35 PM PST