April 5th 05, 01:18 AM
http://www.inl.gov/featurestories/2005-04-04.shtml
Chemical guidebook may help Mars rover track extraterrestrial life
Contributed by Regina Nuzzo
Idaho National Laboratory
April 4, 2005
To help a NASA rover eventually hunt for life on Mars, scientists are
writing a chemical guidebook to aid the search for extraterrestrial
life. Using new imaging tools and earthly parallels of ancient Mars
environments, they're recording the types of subtle chemical changes
that Martian microbes may have left on the planet's rocks.
The researchers hope someday to arm a Mars rover with a suite of tools
-
a guidebook, precise chemical imagers, and human-like reasoning ability
- and let it search for signs of alien life on its own.
Scientists from the U.S. Department of Energy's Idaho National
Laboratory, University of Idaho, and University of Montana are
developing the chemical guidebook as part of what they hope will be a
definitive method to determine whether extraterrestrial rocks have ever
harbored life.
The group, supported by a $900,000 grant from the NASA Astrobiology
Program, will be using chemical imaging technology that was previously
developed at the INL and awarded a patent in November 2004.
The technology will be discussed during the 15th Annual Goldschmidt
Conference, "A Voyage of Discovery," the premier annual meeting in
geochemistry and mineralogy. The conference will be in Moscow, Idaho,
May 20-25, and will mark the 50th anniversary of the Geochemical
Society.
In 1996, a group of scientists reported they had found evidence of life
on a Martian meteorite. But the claims are still controversial, said
Daphne Stoner, project leader and chemistry research professor at the
University of Idaho in Idaho Falls. The debates highlight the need for
clear methods that will distinguish so-called "biosignatures' from
look-alike signs of life.
"This project will help build a good gold standard for the unequivocal
determination of life on extraterrestrial materials," Stoner said.
Stoner is collaborating with chemist Jill Scott at INL, geologist Nancy
Hinman at University of Montana in Missoula, post-doctoral geochemist
Beizhan Yan at the University of Idaho, and geology graduate student J.
Michelle Kotler at the University of Montana.
Mars -- the red planet
Recent discoveries indicate significant amounts of water might still
exist beneath the barren surface of Mars -- an intriguing prospect for
scientists seeking to determine if life forms once existed -- or still
exist -- on the red planet. (NASA photo)
The team is using a specialized mass spectrometer to take chemical
images of microbes and rocks under conditions close to what might be
found on Mars, as well as developing a fuzzy logic computer program to
decipher those spectral pictures. The researchers will take advantage
of
local exotic microbes to test the system's ability to identify signs of
microbial life in minerals here on Earth.
The key to finding signs of unfamiliar life is recognizing that all
organisms must change their environment somehow as they breathe and
eat,
Scott said, even if they don't breathe or eat the same chemicals that
we're used to.
Stoner compares the idea to how even careful humans will still leave
behind traces of their presence when camping. "You can notice a
backcountry campsite," Stoner said. "It looks different from the forest
around it."
So the researchers want to scour Martian rocks in search of the
unexpected. With luck, they'll stumble across the remnants of a
microbe.
If not, they could still glean useful information from surprises in the
rock's composition.
"We can ask, 'Is there something extra there, something not common? Or
is there something that's missing -- some minerals leached away?'"
Stoner explained.
Some chemical changes, for instance, would arise as organisms use raw
material in their environment for food and deposit other chemicals as
waste. These clues may remain even after the organism itself has moved
on or died and decayed beyond detection, Stoner said. The researchers
expect these environmental anomalies to show up in detailed chemical
images, called spectra, taken from samples of the planet's rocky
surface.
Before scientists teach a rover to analyze these clues on Mars, though,
they need to train it on easier things on Earth, Hinman said. First,
the
team will work in the lab with basic biomolecules, such as amino acids
or DNA fragments, sprayed onto a background of minerals commonly found
on Mars, such as iron-rich basalt. Then the researchers will move on to
living microbes and see how they might affect various rocky
environments, Scott said.
Lastly, the team will leave the lab and train their system, using
exotic
microbes found on Earth called extremophiles. These bacteria thrive in
extreme environments such as high-heat, low-oxygen geothermal pools.
Because they rely on sulfur and iron for energy sources - rather than
the plant-based food that humans prefer - extremophiles are good
examples of the type of adaptable microbes that might survive on Mars.
Two sophisticated research tools will aid in building the chemical
guidebook. The recently-patented Laser and Optical Chemical Imager
(LOCI) combines a laser positioning system with a device known as a
Fourier-transform mass spectrometer.
The LOCI's laser can blast a rock's surface and lift off a very thin
top
layer of material as a small gas cloud. Sensors then create spectral
images of the cloud, and scientists can decide what the surface layers
were made of - minerals such as iron, say, with a sprinkling of
microbial waste products.
A LOCI-type instrument would be well suited for the sorts of tricky
situations Mars is likely to pose, Scott said. For instance, it could
do
tests on the spot, freeing the rover up to haul less cargo back to
Earth. "Rock samples from Mars are going to be precious," Scott said.
"We want to bring back the ones with the best chance of showing signs
of
life."
To help make these decisions, a fuzzy logic computer program called the
Spectral IDentification Inference Engine (SIDIE) would supply the Mars
rover with some extra brains. The SIDIE, developed at the INL, uses an
open-ended reasoning approach that mimics a human's decision-making
abilities and learning. "Fuzzy logic is a very powerful technique,"
Scott said.
The program can analyze spectral images very quickly, report the level
of uncertainty in its conclusions, build on information from
neighboring
rocks, and even learn from past experiences - all of which will speed
along the human analyst's job.
"The other nice thing is that it's easy for a user to understand the
decision-making process," Scott said.
Chemical guidebook may help Mars rover track extraterrestrial life
Contributed by Regina Nuzzo
Idaho National Laboratory
April 4, 2005
To help a NASA rover eventually hunt for life on Mars, scientists are
writing a chemical guidebook to aid the search for extraterrestrial
life. Using new imaging tools and earthly parallels of ancient Mars
environments, they're recording the types of subtle chemical changes
that Martian microbes may have left on the planet's rocks.
The researchers hope someday to arm a Mars rover with a suite of tools
-
a guidebook, precise chemical imagers, and human-like reasoning ability
- and let it search for signs of alien life on its own.
Scientists from the U.S. Department of Energy's Idaho National
Laboratory, University of Idaho, and University of Montana are
developing the chemical guidebook as part of what they hope will be a
definitive method to determine whether extraterrestrial rocks have ever
harbored life.
The group, supported by a $900,000 grant from the NASA Astrobiology
Program, will be using chemical imaging technology that was previously
developed at the INL and awarded a patent in November 2004.
The technology will be discussed during the 15th Annual Goldschmidt
Conference, "A Voyage of Discovery," the premier annual meeting in
geochemistry and mineralogy. The conference will be in Moscow, Idaho,
May 20-25, and will mark the 50th anniversary of the Geochemical
Society.
In 1996, a group of scientists reported they had found evidence of life
on a Martian meteorite. But the claims are still controversial, said
Daphne Stoner, project leader and chemistry research professor at the
University of Idaho in Idaho Falls. The debates highlight the need for
clear methods that will distinguish so-called "biosignatures' from
look-alike signs of life.
"This project will help build a good gold standard for the unequivocal
determination of life on extraterrestrial materials," Stoner said.
Stoner is collaborating with chemist Jill Scott at INL, geologist Nancy
Hinman at University of Montana in Missoula, post-doctoral geochemist
Beizhan Yan at the University of Idaho, and geology graduate student J.
Michelle Kotler at the University of Montana.
Mars -- the red planet
Recent discoveries indicate significant amounts of water might still
exist beneath the barren surface of Mars -- an intriguing prospect for
scientists seeking to determine if life forms once existed -- or still
exist -- on the red planet. (NASA photo)
The team is using a specialized mass spectrometer to take chemical
images of microbes and rocks under conditions close to what might be
found on Mars, as well as developing a fuzzy logic computer program to
decipher those spectral pictures. The researchers will take advantage
of
local exotic microbes to test the system's ability to identify signs of
microbial life in minerals here on Earth.
The key to finding signs of unfamiliar life is recognizing that all
organisms must change their environment somehow as they breathe and
eat,
Scott said, even if they don't breathe or eat the same chemicals that
we're used to.
Stoner compares the idea to how even careful humans will still leave
behind traces of their presence when camping. "You can notice a
backcountry campsite," Stoner said. "It looks different from the forest
around it."
So the researchers want to scour Martian rocks in search of the
unexpected. With luck, they'll stumble across the remnants of a
microbe.
If not, they could still glean useful information from surprises in the
rock's composition.
"We can ask, 'Is there something extra there, something not common? Or
is there something that's missing -- some minerals leached away?'"
Stoner explained.
Some chemical changes, for instance, would arise as organisms use raw
material in their environment for food and deposit other chemicals as
waste. These clues may remain even after the organism itself has moved
on or died and decayed beyond detection, Stoner said. The researchers
expect these environmental anomalies to show up in detailed chemical
images, called spectra, taken from samples of the planet's rocky
surface.
Before scientists teach a rover to analyze these clues on Mars, though,
they need to train it on easier things on Earth, Hinman said. First,
the
team will work in the lab with basic biomolecules, such as amino acids
or DNA fragments, sprayed onto a background of minerals commonly found
on Mars, such as iron-rich basalt. Then the researchers will move on to
living microbes and see how they might affect various rocky
environments, Scott said.
Lastly, the team will leave the lab and train their system, using
exotic
microbes found on Earth called extremophiles. These bacteria thrive in
extreme environments such as high-heat, low-oxygen geothermal pools.
Because they rely on sulfur and iron for energy sources - rather than
the plant-based food that humans prefer - extremophiles are good
examples of the type of adaptable microbes that might survive on Mars.
Two sophisticated research tools will aid in building the chemical
guidebook. The recently-patented Laser and Optical Chemical Imager
(LOCI) combines a laser positioning system with a device known as a
Fourier-transform mass spectrometer.
The LOCI's laser can blast a rock's surface and lift off a very thin
top
layer of material as a small gas cloud. Sensors then create spectral
images of the cloud, and scientists can decide what the surface layers
were made of - minerals such as iron, say, with a sprinkling of
microbial waste products.
A LOCI-type instrument would be well suited for the sorts of tricky
situations Mars is likely to pose, Scott said. For instance, it could
do
tests on the spot, freeing the rover up to haul less cargo back to
Earth. "Rock samples from Mars are going to be precious," Scott said.
"We want to bring back the ones with the best chance of showing signs
of
life."
To help make these decisions, a fuzzy logic computer program called the
Spectral IDentification Inference Engine (SIDIE) would supply the Mars
rover with some extra brains. The SIDIE, developed at the INL, uses an
open-ended reasoning approach that mimics a human's decision-making
abilities and learning. "Fuzzy logic is a very powerful technique,"
Scott said.
The program can analyze spectral images very quickly, report the level
of uncertainty in its conclusions, build on information from
neighboring
rocks, and even learn from past experiences - all of which will speed
along the human analyst's job.
"The other nice thing is that it's easy for a user to understand the
decision-making process," Scott said.