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Somewhere out there, the first Mars explorer is getting ready. I often wonder who it will be. A young woman from the U.S.? A man from Africa or Europe? A member of a multi-national team that spent years living and training on Earth and then the Moon?

The state of Mars exploration today is largely dependent on orbiters and landers. This is as it should be. These workhorse robots are doing the advance work for future generations of human explorers. Due to the work that the Mars rovers are doing, for example, future Mars geologists (areologists?) will know what to look for when they study the rugged terrain and now-familiar rocks on the surface of the planet. The mappers will have given us the most detailed surface maps, suitable for charting out the course of human exploration of the Red Planet. Even the Hubble Space Telescope comes in for some Mars exploration, charting long-term changes of the planet as seen from Earth orbit.

Eventually, however, humans will figure out the mechanisms for getting to Mars, exploring it, and living there for long periods of time. That will be, as a friend of mine at NASA once said, “time to quit messing around and actually DOING the heavy work of Mars exploration.” (Well, he didn’t say “messing around” but you get the idea. He IS a supporter of human exploration of Mars, even as he recognizes the need for precursor robot explorations.)

Science fiction writers have long explored Mars. One of the most realistic depictions of life on Mars comes in the book Mars Crossing by Geoffrey Landis. It’s a very scientific look at the very human enterprise of exploring Mars. The attention to detail gave me a few “I didn’t know that” moments, such as the fact that due to the heavy hydrogen peroxide content of the Mars surface and atmosphere, visitors who are exposed to it (and it would be inevitable on a long-term exploration) would find their hair bleaching out! Who’d a thought Mars would be the ultimate hair salon!

Blonding hair notwithstanding, human visitors to Mars will be profoundly changed by the experience in many ways. Witness the life-changing experiences that astronauts who have only visited the Moon and low-Earth orbit have described when talking about their work in space. I can only imagine our first Mars explorer standing there on the new frontier, looking around the dusty, desert surface, and then searching out Earth in the night-time Martian sky. It won’t be much larger than that famous “pale blue dot” that the late Carl Sagan was so fond of describing. I wonder what they’ll say when faced with the enormity of the distance they’ve traveled? Perhaps, like Neil Armstrong did when HE reached the Moon in 1969, they’ll have a prepared speech to share with those of us left back home. I just hope it will be peppered with a few repetitions of “wow!” and “It’s so beautiful!”

Could it Zero in on Enceladus?

Some years ago I wrote a planetarium show for the Springfield, Massachusetts facility about the search for life in the universe. The show, which Mark and I sell through Loch Ness Productions, is called Oceans in Space. In it, we talk about the formation of life on our planet, and then look around the solar system for other places where the basic needs of life (water, warmth, organic material) could be met. We implied that some of the frozen water worlds of the outer solar system, like Europa, for example, could be considered as likely places where life might get a foothold.

The tortured surface of Saturns moon Enceladus belies ongoing geological activity.The enhanced color view of Enceladus seen here is largely of the southern hemisphere and includes the south polar terrain at the bottom of the image.The south polar terrain is marked by a striking set of blue fractures called Tiger Stripes, and encircled by a conspicuous and continuous chain of folds and ridges. Planetary scientists are still making models to explain why this moon is so active. — The tortured surface of Saturn's moon Enceladus belies ongoing geological activity.The enhanced color view of Enceladus seen here is largely of the southern hemisphere and includes the south polar terrain at the bottom of the image.The south polar terrain is marked by a striking set of 'blue' fractures called "Tiger Stripes," and encircled by a conspicuous and continuous chain of folds and ridges. Planetary scientists are still making models to explain why this moon is so active.

Another world often discussed as a possible life-bearing place is Enceladus, one of the larger Saturnian moons. It shows a number of different kinds of surface units (five terrain types, if you will), including areas that are clearly recently resurfaced from within. That means that something is heating Enceladus from within, forcing fluid to ooze out over the surface (or, possibly as ice geysers) and refreezing (which would cover up any craters or cracks that existed there).

Since heat is one of the “feeders” of life, and there’s heat generated inside Enceladus (likely from tidal heating caused by gravitational squeezing), and there seems be water on (and in) Enceladus, it would make sense that life could exist on (or in) that moon, provided that life had some sort of food (chemical or biological) to feed on.

Well, as it turns out, Enceladus may not be as water-rich or hospitable to life as scientists thought. New models of this moon’s interior, based on data supplied by the Cassini spacecraft in orbit in the Saturn system and discussed in this press release, suggest that maybe what we’re seeing on this moon’s surface may not be driven by the action of liquid water inside the moon. Instead, it might be caused by what researchers call the “dissociation of clathrate ices.” Clathrates are ice compounds in which one kind of ice (say, water) is imprisoned in a matrix of another kind of ice (ammonia or methane, for example). In this case, Enceladus may well have a heat source that only needs to heat the ice a little in order to melt the ice shell. The release of some gases in the process would be enough to send plumes of material out and re-coat the surface. This may mean that there’s less water on Enceladus than scientists previously estimated.

This isn’t a kiss of death in the search for life in our solar system. It just means that one of the main components necessary to help life along on Enceladus isn’t so abundant, making that moon less hospitable to life.

What I like about this story is that the finding IS a confirmation that the observations we’re making over the long term in the outer solar system are teaching us about the mechanisms that shape those worlds, including the roles of other chemical and geological processes in icy worlds. And, just because those worlds MIGHT be able to harbor life doesn’t mean they actually HAVE life—a distinction that I rarely see made in media reports about the search for extra-terrestrial life. It’s one thing for a world to have the capability to sustain life (or even have the conditions where life could form). It’s quite another to actually prove that life exists there. To do that, we have to see the life and we have to understand the complex chemical and geological conditions that exist there.

The Spacewriter's Ramblings

A Future on Mars

The Search for Life

Could it Zero in on Enceladus?

Exploring Science and the Cosmos