Making Mars Ours

Dreamers and doers meet at NASA conference on colonizing the Red Planet

Carl T. Hall / SF Chronicle 30oct00

NASA laid out a scaled-back plan last week for the exploration of Mars, hoping to overcome the recent failure of two high-profile missions and still solve the ancient puzzle of whether there might be life on the Red Planet.

Answering that question may seem ambitious enough for an agency trying to stretch scarce resources. But for some space visionaries, the search for life on Mars is only a modest prelude to a much grander adventure: bringing Mars to life.

The powerful pull Mars exerts on the human imagination was evident when about 150 physicists, biologists and space engineers spent two days at NASA's Ames Research Center in Mountain View kicking around the latest schemes for ``terraforming'' Earth's nearest planetary neighbor.

The tone was serious and technical, but the ideas about how to make Mars habitable for humans ranged from the outlandish to the merely fantastic.

There's the idea of steering an asteroid into near-Mars orbit to serve as a handy source of raw materials. Or perhaps genetic engineering can be used to tweak a few earthly life forms into suitable shape to serve as Martian pioneers.

Plutonium Proposal

If that's not scary enough, there are proposals to use surplus weapons-grade plutonium to power Martian reactors, providing a source of energy on that planet while solving the long-term disposal problems on this one. Never mind the additional risk on the launching pad or en route -- advocates figure space engineers will eventually figure something out.

Or perhaps giant, super-light mirrors might be constructed in space and then placed in geosynchronous Martian orbit, aimed to help reflect precious sunlight.

Much of it sounded like potential plot lines for the next ``Batman'' movie. Recent miscues in the space program raise doubts about even the preliminary stage of robotic exploration of the planet, and there are no current plans to send astronauts to Mars.

Harsh Realities

So, there are problems -- to put it mildly -- with the idea of creating a sustainable biosphere out of a planet all but devoid of an atmosphere, raked by UV radiation, with one-third the gravity of Earth and where surface temperatures rarely get anywhere near the freezing point for water.

And yet some serious scientists argued that grand feats of planetary engineering may be possible. All things considered, ``the evidence is pointing to feasibility,'' insisted Chris McKay, an astrobiologist at NASA-Ames who organized the two-day conference.

The most down-to-earth proposals envisioned using heat-trapping ``greenhouse'' gases to warm Mars just enough to allow a rudimentary atmosphere to form. The gases could be created by melting frozen carbon dioxide trapped at the poles or just beneath the dry, subfreezing surface.

New research suggests that synthetic molecules might be devised with novel ``super-greenhouse'' effects. Such molecules could be strung on chemical strands that might be woven into a radiation-stopping blanket, preventing heat from escaping the bitter-cold planet.

One particularly potent molecule was just discovered in Earth's atmosphere -- an ``accidental'' super-greenhouse gas called trifluoromethyl sulfur pentafluoride. It's apparently the product of other industrial chemicals reacting in the atmosphere, has a life span of 1,000 years and, molecule for molecule, has the strongest radiation-blocking effects of any substance known.

Warming a Planet Margarita Marinova of the Massachusetts Institute of Technology offered calculations suggesting that a relatively small amount of the right gases might be enough to get things started. ``Greenhouse gases are a very good method for warming up a planet,'' she said.

That seems to be the same conclusion reached by many climate experts who fear that the burning of fossil fuels may be transforming the weather on Earth. But just because something is bad on one planet doesn't mean it's bad everywhere under the sun.

``Pollution on Earth can be medicine for Mars,'' McKay said. Whether Mars really needs any such medicine is up for debate.

The focus of the NASA-Ames gathering was to address the technical, how-to aspects of planetary engineering. A separate conference is planned to delve into the ethical dimensions -- whether terraforming Mars, assuming it could be done, should even be tried at all.

Many average earthlings seem deeply troubled by the idea, if a recent sampling of sentiment in downtown San Francisco is any indication.

``We've already messed up one planet, so now we're going to mess up another one?'' asked Lucy Rodriguez, a San Francisco-based flight attendant. ``It won't work. We should leave Mars alone.''

But others seem more intrigued by the possibilities of creating what British terraforming champion Martyn Fogg called ``stable bioregenerative life-support systems, energized by the sun'' -- a cozy home away from home on Mars, in other words, just 35 million miles away.

``I think that's a great idea,'' said Craig Harris, 32-year-old national sales manager for the Ritz Carlton hotel chain. ``If we have the technology to do it, it's something we should consider.''

6-Decades-Old Idea

It's an idea long championed by science-fiction writers. Even the word ``terraforming'' has sci-fi origins, attributed to the writer Jack Williamson in the novella ``Collision Orbit,'' published in the July 1942 issue of Astounding Science Fiction.

Judging from the latest scientific take on the subject, Mars is by far the most likely candidate for terraforming.

The latest evidence strongly suggests that the Martian surface once coursed with liquid water. Although the planet is thought to have dried out billions of years ago, a slim possibility exists that some microbial life forms that might have once thrived on Mars may be there still -- perhaps in a dormant form beneath the surface or eking out a living at volcanic sites.

Still, there is no direct evidence that any life now exists on the planet. And while it will take considerably more exploration to be certain, from the standpoint of would-be terraformers, the Red Planet is tabula rasa -- a blank page, practically begging for something to happen.

Other prospects for terraforming seem intriguing but have been ruled out for one reason or another.

Titan, for example, one of the moons of Saturn, already boasts an atmosphere thicker than Earth's. But the air on Titan is devoid of oxygen, the average surface temperature is minus 288 degrees Fahrenheit, and it's a whopping 10 astronomical units away -- 10 times the distance from Earth to the sun.

Mars, by comparison, averages minus 81 degrees, balmy by Titan standards.

It might take as little as 50 to 100 years to get Mars warm enough to unlock the frozen carbon dioxide and form an atmosphere, according to calculations presented by Robert Zubrin, an astronautical engineer and president of the Mars Society.

Such Martian air would be deadly for humans to breathe, but it would at least allow colonizers to walk around without having to wear bulky pressure suits.

It's a challenge that must be taken up, insisted Zubrin, whose latest book, ``Entering Space,'' lays out the case for ``creating a spacefaring civilization'' and ``the establishment of humanity as a multi-planet species.''

``I think Mars will be terraformed,'' Zubrin said. ``It's the nature of life to transform barren places into hospitable places.''

BRINGING MARS TO LIFE

Exploring Mars for signs of life may seem ambitious enough for today's space program, but some visionaries suggest a much grander vision: changing Mars into a habitable planet through a long, slow process called ``terraforming.'' Here's a look at how it might happen: 1. Greenhouse gases are used to warm the planet. This might cause a rudimentary atmosphere to form in 50 to 100 years from carbon dioxide now thought to be trapped at the polar caps. Some suspect enough ice could be melted to form an ocean 1,500 feet deep after another 500 years of warming. 2. A warmer, wetter Mars would still not have a breathable atmosphere. But human colonists could at least roam about the surface without pressure suits, wearing only a portable breathing apparatus while coaxing early microbes and plants to life. 3. It would take about 100,000 years for unmanaged photosynthesis to produce enough oxygen for unaided breathing, but various techniques have been proposed that might reduce the time to less than 10,000 years. One scenario suggests abundant grasses and trees within about 1,000 years after sending in the microbes and mosses.

Source: Chris McKay