Astrobiology Institute tackles basic questions of life

Astrobiology Institute tackles basic questions of life

By JIM DAWSON

(February 4, 1999 12:24 a.m. EST http://www.nandotimes.com) - On April 20, 1967, the Surveyor 3 spacecraft landed on the moon, and arriving with it was a creature from Earth - Streptococcus mitis.

When Surveyor 3 was being prepared for launch, somebody apparently coughed on it, and a colony of the common, harmless bacteria was established on a piece of foam insulation that covered one of Surveyor's circuit boards.

The bacteria contamination was discovered in 1969 when Apollo 12 astronauts Pete Conrad and Alan Bean brought back a piece of Surveyor's insulation. The bacteria had been freeze-dried in space, but were quickly revived once back on Earth.

So bacteria, the earliest and most common form of life on Earth, were also the first life form to travel to the moon. The Surveyor contamination accident revealed that bacteria could survive a launch, travel unprotected through the vacuum of space and survive three years on the moon's surface - a place of high radiation, temperatures near absolute zero, and no nutrients. Once dropped into a nutrient-rich petri dish back on Earth, the bacteria came out of "hibernation" and popped back to life.

The lesson of the streptococcus space colony wasn't lost on NASA. It showed that life could survive in very harsh environments, even extraterrestrial ones.

Now, more than three decades after the bacteria went to the moon, NASA is establishing the Astrobiology Institute, a joint effort of 11 laboratories - university, private and government - to study life in a unique way. By pulling together researchers from biology, chemistry, genetics, geology, planetary science, astronomy and other scientific fields, the institute plans to apply "hard science" to such philosophical questions as: Where did we come from? Are we alone in the universe? Can we migrate to and transform other planets?

The institute is a scientific response to recent discoveries on the Earth, in the solar system and beyond. Institute scientists, in talks and papers presented at the annual meeting of the American Association for the Advancement of Science, which ended last week, noted several discoveries that, as one said, "have changed our view of the potential for life in the universe":

--The discovery in recent years of more planets outside our solar system than in it. Observations, especially with the Hubble Space Telescope, have shown that planet formation seems to be fairly common around stars.

--The realization that life can live under extreme conditions. Biologist Jonathan Trent, in a discussion about a host of terrestrial life forms known as extremophiles, noted that organisms have been found on Earth that can survive in temperatures beyond the boiling point of water, many degrees below freezing, 2.5 miles underground, in extreme acid and base conditions, and even in high radiation inside of a nuclear reactor.

Trent, of NASA's Ames Research Center at Moffett Field, Calif., said that as much as we know about life on Earth, there is an incredible amount we don't know. "We only know about one-tenth of one percent of the microbes that live in the sea," he said. Of the microscopic creatures in freshwater environments and soils, he said, we've identified fewer than 1 percent.

--The discovery that water once flowed on the surface of Mars and may exist below the surface under conditions that would support life as we know it on Earth. A similar discovery raises the possibility of an ocean of liquid water under the ice crust of Europa, one of Jupiter's moons. If Europa's ocean has hot vents or volcanoes on the ocean floor, Trent said, creatures could live there as they do around ocean vents on Earth.

--The realization that life on Earth can be traced back 3.8 billion years, meaning that life began within a billion years of our planet's formation. Because life began quickly on Earth, it also might have begun quickly on Mars, a planet that is believed to have had a dense atmosphere, flowing water and perhaps vast oceans early in its existence.

"Mars had about a 200-million-year period when life could have gotten started," said Jack Farmer, a geologist at Arizona State University and a member of the Astrobiology Institute. Mars became an apparently dead planet as long as 3.5 billion years ago when it lost almost all of its atmosphere. No one is sure what happened to the water, Farmer said, "but maybe it went under the surface. There could be a biosphere - an environment filled with life, probably microbial - on Mars waiting for us to discover it."

Although that might have sounded like wishful thinking only a few years ago, microbes have been found living a couple of miles under the Earth's surface, where conditions might not be much different than they are under the Martian surface.

--The development of bioengineering, which could allow humans to intentionally and quickly develop biological adaptations for themselves, plants, animals and other living things to help with the move into space.

"Humanity may be entering a new evolutionary territory - space - in a manner analogous to the first sea creature crawling out onto the land," said Emily Morey-Holton, a biologist at the Ames Research Center. "This time, however, we are able to document this evolutionary trajectory with modern molecular-biology tools and to engineer the artificial ecologies for evolutionary success."

One of Morey-Holton's particular concerns as life moves off Earth is the role of gravity in everyday life, and in the subtle mechanisms of evolution.

"We live with a one-G environment," she said, referring to the gravitational force that governs us here on Earth. "But as we move out, we have to have a multi-G mentality." Humans living in space, on the moon, on Mars and perhaps other planets will all experience different levels of gravity depending on where they are, she said, and each level of gravity will present unique challenges.

Astronauts working in zero-G already have realized that without gravity, water won't percolate through soil. That makes something as simple as watering a plant a difficult problem. Other processes such as convection and sedimentation, both important climatic and geological phenomena on Earth, don't occur at all in the zero-gravity of space and may not work well in a low-gravity colony on Mars or the moon.

Another interesting question, Morey-Holton said, is what happens to humans who grow up in space, on the moon or Mars? Evolution has given us bodies suited for one G. What happens to bodies developing over generations in lower or higher gravity? Could a person who grows up on Mars find the Earth's stronger gravity overwhelming and be unable to return to the "home planet?"

The questions being addressed by the Astrobiology Institute are seemingly endless, and many are profound. Until now the work that many of these scientists are doing has been the stuff of science fiction. Now, with the establishment of the field of astrobiology, the line between the fiction of the past and the reality of the future seems to be blurring.

The Astrobiology Institute, backed by more than $15 million in federal funding for the next year, is much more than a group of scientists theorizing about what might be out there. In December, two basketball-sized aero-shells will crash onto the Martian surface and release probes that will punch several feet into the soil in search of water. During the next few years more landers will descend on Mars, all looking for signs of life - or past life.

In 2003 a spacecraft will head for Europa in search of the ocean that may be hidden beneath the ice. A life-seeking lander might not be far behind. In 2004 a spacecraft already on its way to Saturn will drop a probe onto Titan, a moon with a dense atmosphere of nitrogen - an ingredient for life as we know it. Another mission, the Titan Biologic Explorer is already on the drawing boards. Sampling missions are also scheduled to land on passing comets to see if they really are the water carriers of the solar system, as some scientists suspect.

Almost all the missions in space for the next decade seem aimed at finding evidence of life out there. While probes look for extraterrestrial life, Earth-bound biologists will push harder to understand what life is and how it comes to be. Finally, there are the scientists such as Morey-Holton who, as she said, will be "looking at how life might be moved beyond our home planet. Humans now have the potential to direct life beyond Earth."

By JIM DAWSON, Minneapolis-St. Paul Star Tribune. Distributed by Scripps Howard News Service.