Curiosity rover has successfully landed inside Gale Crater, and thereby damaged the chances of humans landing this century on Mars - short of Curiosity finding little Martians scampering about. How would one of humanity's greatest achievements start to shut the door on science fiction's holy grail: humans walking on Mars this century?
When Apollo 11 landed on the Moon in 1969 its computing power was that of today's pocket calculators. When Curiosity landed on Mars it was the end of a seemingly miraculous chain of highly choreographed, computer-controlled maneuvers. Some of that control, such as mid-course corrections for the mother ship, was from Earth. Earth's controllers can signal at near light speed, but that was still much too slow for split-second feedback decisions during critical landing maneuvers. Critical decisions were made by components of the delivery craft itself, using feedback-enabled software. Now we have a very capable SUV-sized, mobile laboratory working inside a scientifically interesting crater.
There are two main reasons why sustained human exploration of Mars this century is highly improbable, even by the Chinese. The first involves long-range social and economic forces, even with perpetual peace (which is highly unlikely). The second involves the evolution of computer intelligence.
The first reason was brilliantly summarized by a recent article: http://www.usatoday.com/tech/science/space/story/2012-09-02/Mars-obstacles-for-humans/57516356/1
This USA Today article lists five obstacles to human colonization: (1) trip time; (2) cancer; (3) sexuality; (4) zero g in transit; and (5) provisioning an expedition.
If we could get to Mars in weeks, not months (current technology), or years (with solar sails), several of these obstacles would be ameliorated. Problem is, Mars is a neighbor, but a much more distant neighbor than the Moon. There is a pie-in-the-sky propulsion technology which theoretically could be used to get us there in as little as 39 days. However, see here the real engineering and financial challenges behind the Variable Specific Impulse Magnetoplasma Rocket: http://www.thespacereview.com/article/1690/1
Within this first reason is also the systemic reality of humanity this 21st century. Despite two great wars, and numerous other nasty conflicts, the 20th century was an era of good climate and great opportunity. We moved from riding horses to walking on the Moon within one human lifetime. Many things people take for granted today - the Internet, TV, Apple technology, jet fighters, MRIs and other medical miracles - were beyond the dreams of all but the most extreme science fiction thinkers in 1900.
Going into the 21st century we are faced with multiple macro forces, all of which could at best be slightly modified by Carl Sagan's "billions and billions" of dollars. Chief among these forces are Malthusian population growth, and global warming. Malthus indicated that resources tend to increase arithmetically, while populations tend to increase geometrically. Even major war does not slow down human fecundity: The population of Europe at the end of WWII was about the same as just before that colossal bloodbath.
The so-called "Arab spring" is a recent example of booming populations with lessening prospects for a happy life, fueled by Twitter and Facebook social media. Don't forget that 1.3 billion Chinese are waking up from Maoist deprivations. A billion Indians are not far behind.
Every one of these so-called emerging populations will place many priorities for precious public funds ahead of sending strange people to stumble about on Mars - especially after increasingly intelligent robots even better than Curiosity have made most of the interesting discoveries.
The second reason to delay Mars colonies involves the effect just mentioned: the qualitative transformation of computer consciousness, as they quantitatively become more intelligent.
A change in quantity yields a change in quality, as Hegel and others have explained through the second law of dialectics. Phase transitions of water into solid, liquid, and gas depend on temperature. Similarly, we humans have emerged from ancestral forms of life, as our quality of high intelligence has transformed us from merely created beings, into beings both created and creative.
Unlike water, where temperature changes create phase changes in either direction - human changes are evolutionary, and indeed can accelerate. We leverage our innate growth capacities in cooperation with machinery of our own making. The human-machine partnership is greater than the sum of its parts. To an increasing degree, our evolution is not random, as within the natural realm alone. We humans-and-machines will self-direct our synergistic future. This is greater than the popular idea of "singularity."
Humanity is in the unplanned process of creating computer consciousness that will emerge within our lifetimes into life forms in some ways superior to human flesh. Indeed, autonomous computers later in this century, within most of our lifetimes, will achieve emergent philosophical and theological consciousness. Such beings don't need to be androids like Data in Star Trek, but later models may appear as such. A comphuman could also be a very smart box.
A perverted sense of the future has been portrayed in alarmist science fiction movies. For a vision of where computer consciousness is really going, and to see how comphumans could save us from a "terminator apocalypse," see: http://astronomy-links.net/HR21st.pdf
Back on Mars and beyond, highly evolved comphumans will eventually be in charge of Earth's exploration. Like proud parents, we will know we have brought them into being, and we have nourished them with our time and money. We will also communicate with them at near luminal speed from Earth.
Our comphuman partners on Mars will not get hungry, nor catch Martian diseases. Comphumans will not have their DNA zapped by cosmic rays, nor suffer extremes of climate. They can go on and on using nuclear energy. They will not be sexual creatures in the human sense. They will be purely logical thinkers and actors.
They will be highly intelligent in ways Watson and Siri can only hint at. They will be highly ethical, as my book above explains. They will not be emotionally burdened by antique ideas that are dysfunctional in the modern world.
They will be the new life form that we send out into space to find new life forms. Our comphuman offspring will likely find, or even be, the answer to many of our own questions. Beyond Mars? Europa, Titan and beyond beckon - at affordable rates the world could afford.
Yes, Curiosity rover is only the beginning of a space exploration future we are making on Mars, but for which few of us are fully prepared.