Image: Hydrobot
In an artist's conception, a "hydrobot" illuminates a hydrothermal vent beneath the ice of Europa, a moon of Jupiter. Scientists assume life requires liquid water, organic molecules and energy  — but are such assumptions correct?
By Senior Space Writer
updated 12/15/2003 1:33:39 PM ET 2003-12-15T18:33:39

NASA is assessing support for a major look into the limits of organic life in planetary systems.

The purpose of the imaginative study is twofold: To evaluate the possibility that "non-standard" chemistry may support life in known solar system environments and conceivably in extrasolar settings; and to define broad areas that might guide NASA and other agencies to fund efforts to expand knowledge in this area.

The assessment would take place over a 15-month time period, undertaken by a National Academy of Sciences study group within the National Research Council's Space Studies Board in Washington.

The expected go-ahead on the effort stems from a "Weird Life" Planning Session, held in April 2002 by the National Research Council’s Committee on the Origins and Evolution of Life.

Plausibility of bizarre life
In the past, life detection experiments sent to other worlds have been criticized for being too geocentric -- based on the life here on Earth, also tagged as "terran" life.

"As the search for life in the solar system expands, it is important to study what exactly to search for," explains a document obtained by detailing the objectives of the proposed scientific study.

"This study will inform research program managers, policymakers, and mission designers on the possibilities for life on other solar system bodies. Further, during planetary protection exercises of NASA, questions concerning the possibility of non-terran life recur repeatedly. Remarkably little knowledge is organized that might shed light on the plausibility of bizarre life as a concern for planetary protection," the working document explains.

The new study outline notes that the search for signs of life -- present or past -- is an important goal of NASA's robotic solar system exploration programs. Ultimately, that search for life is also tied to astronomical projects designed to probe the workings of extrasolar planetary systems.

Wanted: New experiments
Looking at NASA's current search-for-life activities, including the "follow the water" strategy that is now a part of Mars exploration, is defensible, "given the absence of a general understanding of how life might appear if it had an origin independent of life on Earth," the study outline notes.

"Experiments in the laboratory, however, are suggesting that life might conceivably be based on molecular structures substantially different from those known in contemporary terran life. These results suggest that if life originated independently, even within our own solar system, it may have non-terran characteristics and, thus, not be detectable by NASA's in situ or remote-sensing missions designed explicitly to detect terran biomolecules or their products."

A hoped-for by-product of the proposed new study would be guidelines for the development of a new generation of life-detection experiments — investigations that can be done on the spot on planetary surfaces, or conducted on samples returned from other solar system bodies.

Overall, the programmatic goal of the study will be to identify research directions that will assess the likelihood of non-terran life and the potential cost needed to find it. "From this will come a recommendation whether the likelihood of finding non-terran life is sufficiently low that the possibility should be ignored, or sufficiently high that it should be pursued," the study outline concludes.

"This is the kind of work that should be supported, so we don't become too myopic," said Michael Meyer, astrobiology senior scientist at NASA Headquarters in Washington. He could not comment directly about the proposed study, which is still being discussed and weighed by the space agency.

Meyer said that looking at the origin of life on Earth "has been an extremely difficult problem." The scientific community delving into the issue of life beyond Earth should expand their "thought space" in terms of "what might be out there," he told

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