Read more: 鈥�100,000 AD: Living in the deep future鈥�
IT IS an inescapable fact. The destinations we can visit in outer space will always be limited by the technical challenges of travelling the unimaginable distances involved, especially within a human lifespan. Still, that will not be the only factor shaping where our descendants go. The route that they take into the cosmos will be equally driven by age-old human motivations 鈥� and perhaps even a dash of religious fervour.
First, the bad news. Last year, a group of scientists, engineers and futurists assembled in Orlando, Florida, to plot humanity鈥檚 next era of exploration. The name of the plan was the 100 Year Starship Study. The idea was to begin to work out, over the next century, how to get humans to the nearest stars. You can鈥檛 fault the idea for ambition, but many of them soon realised that developing the necessary technology was daunting, if not fanciful.
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Neal Pellis of the Universities Space Research Association based in Columbia, Maryland, summed up just how far our fastest spacecraft are from achieving interstellar travel. 鈥淭he nearest star is Alpha Centauri,鈥� he told the 100 Year Starship meeting鈥檚 participants. 鈥淎t 25,000 miles per hour, it would take 115,000 years to get there. So this is not a plan.鈥�
Even if we figure out how to travel at the speeds required to arrive at a star in a human lifetime, the energy required to get there is far beyond our means for the foreseeable future. Mark Millis of the , a space-travel think tank based in Fairview Park, Ohio, says only a tiny proportion of today鈥檚 global energy output goes towards space flight. If this state of affairs persists while energy production continues to grow at the rate of recent decades, then interstellar missions are at least two to five centuries away, he calculates ().
For the next few centuries, then, if not thousands of years hence, humanity will be largely confined to the solar system. Even reaching destinations closer to home will remain slow going until we find better propulsion systems than chemical rockets, which are like Columbus鈥檚 ships in terms of speed and technology, says NASA planetary scientist Chris McKay.
Assuming we achieve the speed boost we need, what routes might we take further into space, and what will drive exploration? 杏吧原创s will no doubt continue to send uncrewed probes all over the solar system, but if history is any guide, human exploration and settlement of space will not be driven by scientific curiosity alone.
Roger Launius, NASA鈥檚 former chief historian, now senior curator at the in Washington DC, says that whenever people have ventured into unexplored corners of Earth, their motivation has tended to be 鈥淕od, gold or glory鈥� 鈥� in other words, a drive to convert indigenous peoples or escape religious persecution, or to extract wealth or earn fame.
鈥淲henever people have ventured into unexplored corners, their motivation has tended to be 鈥楪od, gold or glory鈥欌��
In search of glory
Much of human space exploration to date has arguably been motivated by glory. National pride was behind the first crewed space missions and fuelled the colossal investment required to put people on the moon. Political will of the same order will be needed to realise the first Mars walk or human visit to an asteroid.
Further down the track, nations or companies may want to be the first to send astronauts to rocky worlds like Saturn鈥檚 moon Titan, which sports polar lakes of liquid methane. Another tempting expedition would be to Jupiter鈥檚 moon Europa 鈥� especially if the liquid ocean under its surface ice turns out to be home to extreme life forms.
What about God? Could religious motivation play a role in space travel? Future solar-system explorers will have no local aliens to convert, but religion could conceivably be a reason to flee Earth. In the 17th century, for example, English Puritans risked their lives to settle in America for the sake of practising their beliefs. If the private spaceflight industry provides the means, it鈥檚 not impossible that a religious group might be among the first to populate the moon or a Mars base.
Nevertheless, the dominant drivers of exploration in our history have been economic ones, Launius says. For a space economy, mining asteroids has been proposed, as has space tourism, but neither鈥檚 time has come yet. 鈥淲e have yet to find an economic motive to undertake space activities that would involve humans,鈥� Launius says. For example, it鈥檚 impossible to predict what mineral resources will be important to us mere decades from now (see 鈥淲ill we run out of resources?鈥�). By the time it becomes viable to mine, say, platinum from asteroids, humanity鈥檚 demand for that metal may have faded.
Another lesson of history is that exploration has not always been sustained. Instead, it often happens in fits and starts. Consider how the Vikings ventured into North America a thousand years ago, yet permanent European settlement did not follow for another four centuries. Chinese exploration also went on for centuries but ceased by 1500 or thereabouts.
鈥淭here鈥檚 nothing inevitable about space travel,鈥� says John Logsdon, a space-policy researcher at George Washington University in Washington DC. He suggests that subsequent generations may take a break from exploring deep space or even venturing beyond Earth.
Indeed, our descendants may well have to come to terms with never having the means or lifespan to reach other stars. For them, the stars will remain tantalising twinkles of light, forever beyond reach.
Then again, there will always be people, like the delegates to the 100 Year Starship meeting, who will work to keep the dream alive.
