PARIS — No country has yet decided to send anyone to Mars. But private-sector initiatives reported by the media — and the global film industry — suggest that things could change within the next decade.

If nothing else, such efforts are proof of our collective impatience to see a new stage of space exploration and demonstrate that it remains a current and media-friendly topic. It's true that after the magnificent Apollo adventures of nearly 50 years ago, manned spaceflight has been limited to orbiting our cradle, the Earth. So what about this space yearning?

Despite sci-fi's unrestrained imagination, the number of destinations accessible to us in the next 50 years appears very limited. We can already exclude our solar system"s big planets, which are too far away, too gaseous and have gravitational forces that are too strong. Mercury and Venus are also off limits, too hot and inhospitable. As for trips outside of the solar system, it's not worth even thinking about. It would take us 80,000 years to reach Proxima Centauri, the closest star. That leaves us with the subject of hundreds of years of fantasy, Mars, or alternatively its satellites, a few asteroids, maybe even a return to the Moon.

Motivating factors

There are many different reasons for space travel, among them the desire to rise to the technological and human challenge. But we're also seeking answers to the same eternal questions: Where do we come from? Where are we going? Are we alone in the universe

The first goal of space exploration, therefore, is to improve our knowledge. That goes for both manned and unmanned missions. But there are big differences between the two. In the case of space probes, the financial investment is relatively moderate and acceptable for the economies of the biggest nations. Once humans are included in the equation, the costs change dramatically. We're no longer talking about hundreds of million of dollars or euros, but about hundreds of billions. Keep in mind that Apollo cost more than $200 billion. For Mars, the figure would likely be at least twice as big.

[rebelmouse-image 27089559 alt="""" original_size="800x600" expand=1]

Mars Society crew members training on Devon Island, Canada — Photo: Mars Society

Space travel is also driven by the pure and simple impulse to explore, and by the wonder inspired by the sight of the Earth as seen from beyond — beautiful and fragile. And in the case of the Apollo missions, there was another motivating force involved: the political confrontation between capitalism and communism whereby both sides used space as a means of power and prestige.

But what reasons could there be for sending people specifically to Mars? In terms of improving our knowledge, human exploration would likely be useless given ongoing advances in probe technology. And unlike at the time of the lunar missions, the political conditions favoring a new space race just aren't there — despite the growing rivalry between the U.S. and China.

There's still, of course, the pure and simple desire to explore. But given the current state of the world economy, it's hard to imagine that any country would spend several hundred billion dollars just to satisfy that urge, or for the sole amazement of a few privileged astronauts.

New priorities, in the meantime, are also emerging on Earth, such as environmental protection and the fight against climate change, which will require dedicated budgets and large amounts of energy. As for establishing settlements on the Red Planet, we should probably delay that until the 22nd century or later, seeing how difficult and utopian it would be to make Mars habitable.

Question marks

NASA, which published a recent document on the subject of Mars, avoids the issue of cost, focusing solely on the technological and human challenge the trip would represent, not to mention the scientific progress. But rushing headlong into the Martian adventure without having a long-term vision for the next 50 to 100 years would be unreasonable.

[rebelmouse-image 27089560 alt="""" original_size="800x618" expand=1]

An artist's rendering of a human Mars base — Source: NASA Ames Research Center

Considering the considerable initial investment required, deciding whether to go to Mars depends on the existence of a clearly defined goal, and one that would be profitable to us, if possible. And we have to admit that space agencies around the world, and especially NASA, have so far failed to deliver on that point. In the past, triumphant promises by a few U.S. presidents (all of them Republicans) haven't translated into action.

As exploration history shows, the prospect of viable economic and industrial activity is an essential motivating factor. It won't be any different for Mars. The goal would be to exploit the planet's resources, provided there are any and that the prospect is realistic. But as things stand, we just don't know if that's a possibility.

Private companies are trying to take the reins, both for manned flights around the Earth and to Mars. But a crucial question arises: Is a world where any entrepreneurial action has to be justified by returns on investments compatible to space travel? A space program can take as long as several decades. And even if there were a return on investment, which is far from certain, can a company afford to wait that long?

That's why, except for a few private initiatives, human spaceflights will probably remain a government domain, countries being the only entities capable of raising sufficient funds for the required investments.

Other considerable technical challenges can be added to these considerations. There is no precedent, for example, for such a long flight — one that would take about three years. The crew would also need to be protected from radiation. We don't know how to land a spaceship on Mars. We'd need a large quantity of fuel to take off from Mars. And the mission's success would essentially rely on the crew members getting along in a confined area for three years.

But at the same time, isn't it also true that the particularity of space travel has always been to overcome difficulties that were previously thought to be insurmountable. So, will we go to Mars one day? The answer is probably yes, but it won't happen in the near future. A trip to Mars will be a considerable challenge. But the initiative's difficulty and its cost mean that the adventure would probably be limited to one single trip and that, like the Moon, we'd turn away from Mars once the feat is accomplished.

Seeing humans in space is a millenary dream, and dreams often shade the difficulties of their fulfillment. There is, on the other hand, no fulfillment without a dream, though it must also be noted that many dreams remain just that: dreams.