Zack Sweeten - The Battalion

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Aggie scientists search for signs of life on Mars

By: Nick Anthis

Posted: 2/9/05

One by one, seven men and women in clumsy white spacesuits exit their protective base onto the cold and uninviting Martian surface. Steven McDaniel, their captain, observes a harsh landscape covered with jagged, reddish-brown rocks. It seems unlikely that anyone could find signs of life in such a dry and hostile place - but that is exactly what he is looking for.

McDaniel, who received his doctorate in biochemistry from Texas A&M University, is a lawyer and the founder of a biotechnology company. He is also an astronaut.

Well, sort of.

McDaniel and his team are actually on Devon Island in the Canadian Arctic, conducting a simulation of manned exploration of Mars. As a member of the Mars Society, an organization dedicated to "the exploration and settlement of the Red Planet," McDaniel led a one-month expedition in 2003 to M.A.R.S. - a clever and appropriate acronym for the Mars Artic Research Station.

The Mars Society has two research stations in areas that closely resemble the conditions on Mars. Devon Island was chosen because its location in an arctic desert closely resembles the cold and dry surface of Mars.

"It's a hobby," McDaniel said. "It's a serious hobby."

It is also a hobby with serious implications.

McDaniel's mission has many purposes, most related to survival, travel and exploration on a world tens of millions of miles away from Earth. The largest obstacle to overcome, it seems, is the fact that spacesuits are incredibly awkward, and a task as simple as picking up a small rock sometimes requires a solution that would make television's MacGyver proud.

The other purpose was to identify life forms capable of living in such an extreme environment. Recently, the prospects for such life recently became much better with the identification of an ancient Martian sea.

The rover Opportunity landed on the surface of Mars on Jan. 24, 2004. Mark Lemmon, a research scientist in A&M's Department of Atmospheric Sciences, helped monitor Opportunity and related Mars rover, Spirit.

Although Lemmon's primary job was to study Mars' atmosphere, he said, "The rovers weren't sent to study the atmosphere ... The rovers were sent to find past water, and both of them have found it."

Opportunity landed in a region called Meridiani Planum, which was chosen because of the presence of rare deposits of hematite, a mineral often formed by liquid water and mysterious white streaks. Before Opportunity landed, though, scientists did not know whether the hematite deposits were formed by water or volcanic activity.

Opportunity identified the mysterious white streaks as salt deposits, left behind as an ancient sea evaporated, and it found ripples and mud cracks caused by liquid water.

"We found out, as most people suspected, that there had been water there, and we know that for sure now," Lemmon said.

Meridiani once held a body of water at least as large as a small sea. It could have even held a large ocean, but due to Opportunity's limited mobility, scientists do not know its true extent. Opportunity is still functioning, and Lemmon said it will continue driving south to find the boundary of this ancient body of water.

The presence of an ancient sea indicates that the conditions on Mars may have once been similar to the conditions that spawned Earth's first primordial life forms.

There is still water on Mars, but only in the form of ice, due to surface temperatures that rarely climb above freezing and can dip below negative 200 degrees Fahrenheit at the poles. Most of the water on Mars today exists as permafrost below the surface.

Lemmon is working on the Phoenix Lander, which is scheduled to land on Mars in 2008. It will dig into the permafrost to search for salts and organic molecules that could indicate an environment once favorable for life.

"We don't think (Mars) is inhabited now," Lemmon said. "We won't have life detecting equipment, but we're looking to see if there are energy sources for life and things that would kill life."

McDaniel said manned exploration will be necessary to find life on Mars.

"I have been very impressed with the robot missions," McDaniel said, but "robots cannot be intuitive."

He said the "problem-solving computer on your shoulders" is necessary to deal with the unique issues that will arise in the search for life on Mars.

Jim Wild, a professor of biochemistry and genetics at A&M and the advisor under whom McDaniel earned his doctorate, said "all of the conditions we would anticipate being necessary for life existed at some time in Mars' history," including salt, water and a favorable temperature.

Despite these past favorable conditions, it is unlikely that anything more complicated than simple bacteria lives or has lived on Mars.

Wild said the search for life on Mars is similar to the search on Earth for extremophiles - life forms, usually bacteria, that live in extreme conditions. Life on Earth has proven the ability to adapt to conditions that would seem to be extremely inhospitable, including in 250 degrees Fahrenheit water near volcanic vents on the ocean floor.

Some bacteria called lithotrophs can even live inside of rocks. In his mission to M.A.R.S., McDaniel focused on the search for these.

McDaniel said, "if Martian life is there, it probably is a residual life," left over from when Mars was wetter and warmer. "It is probably just holding on to some niche," he said. This life would probably live underground, protected from dangerous radiation and extreme temperatures.

The cold harsh fact remains, though, that no direct evidence has been found for past or present life on Mars. Regardless, we should still consider that the discovery of any life would raise significant ethical issues, including the extent to which humans would affect this extraterrestrial life and how humans could prevent contamination of Mars with life from Earth.

McDaniel said scientists should be extremely careful so that if life is discovered, they can study it without affecting it. That way, "you always have the option to decide as a group that you are going to leave the Martian biosphere alone and let it evolve however it's going to evolve."

If we ever found something as extraordinary as life on Mars, though, could we ever really just leave it alone?