Astrobiology Central to the Future of Planetary Exploration Says Cornell's Steve Squyres
Cornell University’s Steve Squyres said at a NASA teleconference yesterday that the future of planetary exploration is “driven” by astrobiology and the search for life on other celestial bodies.
The teleconference focused on NASA-sponsored astrobiology research directed to finding life on other celestial bodies and featured a panel of researchers who are looking for clues by studying the key components and processes that led to the development of life here on Earth. Dr. John Peters of Montana State University explained that his research focuses on understanding the biological reactions that enable organisms to make iron-sulfur compounds associated with iron-sulfur enzymes. These “complicated metal assemblies,” he said, reflect reactions that are “innately pre-biotic” and he hopes can help understand the transition that led to life on Earth.
Dr. Bill Schopf from UCLA and Dr. Jack Farmer from Arizona State University lead a team focusing on finding the oldest records of life on Earth. Dr. Schopf, who highlighted that scientific cooperation both nationally and internationally is a feature of the field, said they have been looking for 600 million year old microscopic fossils in the Mediterranean Sea – which was at one time completely dried out. They found a variety of organisms – including cyanobacteria (or pond scum) and phytoplankton – embedded in a sulfate mineral called gypsum. The researchers were stimulated to look for bio-signatures in this mineral because of the orbital mapping of Mars by NASA’s Mars Reconnaissance Orbiter, which found large traces of gypsum on the surface. Dr. Farmer explained that the landing of one of NASA’s Mars rovers, Opportunity, on large sulfate deposits also motivated their research. (Dr. Squyres is considered the “father” of the Mars rovers Spirit and Opportunity.)
While NASA-funded researchers are looking for evidence of life on other celestial bodies, outside of NASA others are looking for signs of intelligent extraterrestrial life. The possibility of intelligent life elsewhere in the universe – that might someday visit Earth – is also in the news. Last Sunday, renowned physicist Dr. Stephen Hawking was quoted in the London Times with a warning to humans to avoid the dangerous confrontation that he believes would inevitably ensue from contact with intelligent alien life, saying that “if aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn’t turn out very well for the Native Americans.”
Though the NASA teleconference was not about searching for intelligent life elsewhere in the universe, one reporter asked the panelists about Hawking’s remarks and if they believed humans should continue broadcasting signals that might be detected by other civilizations that could lead them to Earth, or only listen for radio signals from such civilizations. The privately funded SETI Institute, for example, uses a radio telescope array that searches for radio signals that could be from another civilization. Mary Voytek, astrobiology senior scientist at NASA Headquarters, stressed that SETI research is conducted privately and noted that within NASA there is a “difference of opinions” about transmissions. Dr. Squyres added that “Earth has been broadcasting radio signals for decades…[the] signals are out there.”
As for the microbial life on which the NASA-funded research focuses, new data suggests that even asteroids may present such an opportunity. In the April 29 issue of Nature, two teams of scientists report that they found water ice and organic compounds on Asteroid 24 Themis. Water is considered an essential element of life and Dr. Squyres agreed that a mission to an asteroid may be a possibility, saying that objects bearing traces of the necessary conditions for life are “candidate object[s] for study” and said that “we should go where the data lead us.”
In the meantime, the National Research Council’s Planetary Sciences Decadal Survey Committee is crafting its report on recommendations for the future direction of planetary exploration. Dr. Squyres, chairman of the committee, said they are “halfway through” and noted that one of the lessons emerging from their work is that “astrobiology is really central to what we should be doing next.”
According to Squyres, some of the 28 missions under discussion by the Decadal Survey include: exploring Saturn’s moon Encedalus to see if its erupting geysers at the south pole are evidence of water under the surface; returning samples from a comet, believed to be rich in organic materials, the “building blocks of life;” and looking for the sources of methane in the Martian atmosphere and determining whether its replenishment is of biological nature.
One potential mission capturing a lot of attention is a complex 3-step sample return mission to Mars, featuring three vehicles: a rover, a lander, and an orbiter. Dr. Squyres said that this multi-step approach to a mission that has been on the minds of researchers for at least 20 years is more cost-effective than sending a single spacecraft to return a sample of Mars. He added that by “string[ing] those out in time…with gaps of potentially years,” the mission is more affordable in the long run.
In response to a question about the heated debate over NASA’s FY2011 budget request and what should be the future of the human spaceflight program, Dr. Squyres explained that such decisions rarely impact the astrobiology field: “Our program is driven by science…a paradigm that remains unchanged” with respect to architecture decisions for human missions. He said that while some astrobiology researchers do want to see humans on Mars and other destinations, the details over rockets and vehicles “don’t really affect our program.”
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