Robinson Crusoe on Mars

The idea of a one-way, one-astronaut mission to Mars isn't brand new, even in the non-sci-fi world of real space exploration chatter, but it has recently resurfaced in the news. In a nutshell, the reason for the idea of a hop to, but not back from, Mars is a mixture of cost and technical feasibility—that the biggest hurdle in setting humans down on Mars is not the act of doing so, but the conventional returning of the astronauts to Earth.

Technical feasibility and cost and long lists of volunteers potentially interested in being the first person on Mars aside, my thoughts focused in on one main aspect of such a venture: the solitary soul to make the trip. Even if they knew what they were getting into, went through months, or years, of psychological training and conditioning, and said all their goodbyes—can you imagine the life they would be committing to?

Forget about the "normal" risks of space travel; I'm thinking about the fact of absolute planetary solitude, possibly for the rest of one's life. There would be no guarantees that other humans would follow in later missions—even cheap space programs get cancelled. The only guarantee is that you'd never leave Mars.

And no Star-Trekish two-way conversations with folks back on Earth. In the real world, radio signals travel at 186,300 miles per second, making a one-way signal time of three or four minutes at best (at closest approach between Mars and Earth). So you say "hello Earth!" into your microphone, and six to eight minutes later you get a "hello back at you Mars!" (And most of the time, the round-trip hello/hello-back time is much longer.)

Okay, so you have your never-ending power source (nuclear), lifetime supply of food and medicine, entertainment (books, videos, games), and, of course, you're living your dream exploring another planet where no one has gone before—and making huge strides in humankind's exploration of space and understanding of the natural history of a completely different world.

I just can't help think about one of my favorite 60's sci-fi films, Robinson Crusoe on Mars, specifically the piece where the lone astronaut (monkey doesn't count, much) thinks he might go mad in such isolation, with the potential of never being rescued. Or the film version of Journey to the Center of the Earth, when Professor Lindenbrook stared incredulously at the three scratches on a plumb-bob made by his predecessor, and whispered, "Alone…alone!"

Even though our would-be Mars lifer would be going into this voluntarily and deliberately—what if, when they got there, the true reality settled in and they got an unexpected and extreme case of homesickness….

I'm not poo-pooing the idea of sending a person to Mars–even though I am an advocate of the much more achievable robotic exploration of the solar system, and all the knowledge it brings at a relatively affordable price. A scientist on a multi-decade prospecting trip to our neighboring world would reap huge rewards for us all. But, the solitude…the solitude…. (The blogger shakes off a shiver.)

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A limb shot of Mercury's horizon taken by the
MESSENGER spacecraft on January 14, 2008.
Photo Credit "NASA/MESSENGER"

If you can take a name like "Mercury Surface, Space Environment, Geochemistry and Ranging" and craft it into a neat acronym like MESSENGER, then you may have a future working with NASA….

And no, this blog isn't about NASA acronymizations, but rather the heat-resistant robot behind one of them. MESSENGER is the space probe that NASA sent to Mercury to give the Solar System's innermost planet the first up-close look since 1975, when Mariner 10 flew by.

Though MESSENGER's main mission will begin in earnest when it returns to Mercury and finally settles into an orbit around the planet, on March 18th 2011, we were given a tantalizing peak last January 14th when the probe made its initial flyby.

What did this quick, on the fly snapshot tell us that we didn't know before? Well-a lot, considering Mercury has been one of the least understood planets in the Solar System, and was for a long time thought to be similar in character to our own Moon. Mercury is shaping up to be a lot less like Earth's Moon than its gray, cratered, airless appearance would mislead.

One key difference: density-how much material is packed into the planet; or how heavy a standard sized chunk of it would be. Our Moon is a lightweight on this score, with an average density of only 3.4 grams per cubic centimeter, while Mercury weighs in at a hefty 5.427 g/cc-almost as dense as Earth.

Another key difference: magnetic field. Planets like Earth and the Gas Giant worlds (Jupiter et al) generate respectable magnetic force fields, useful for everything from deflecting plasma flowing from the Sun (the "solar wind") to properly directing magnetic compass needles. Venus, Mars, and our Moon do not possess magnetic fields worth mentioning, as it turns out.

Mercury, on the other hand, does. Planetary magnetic fields are believed to be generated by currents in a planet's liquid outer core-like how the electric current in the wire coil of an electromagnet generates a magnetic field. Mercury's magnetic field suggests it still has some activity in its core-molten metals circulating in currents as the core slowly cools off. And speaking of Mercury's core, it appears to comprise 60% of the planet's mass-about twice what is "typical" for Terrestrial (solid) planets.

I've often imagined Mercury to be a cosmic goldmine, with its apparent richness in metals and its density. I wonder if an astronaut could just walk along and pick up chunks of gold from its surface….

Another interesting find by MESSENGER is that some of the flat plains on Mercury may have been formed by volcanoes, long ago. In particular, MESSENGER imaged a number of volcanoes along the edge of the Caloris Basin, a large impact basin-one of the largest in the Solar System, at 1550 kilometers across.

The news coming out of the innermost region of the Solar System makes me giddy. Too bad I have to wait until 2011 for my next look at Mercury. These things take time.

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