|An Historical Aberration|
The Apollo Space Program lasted for 11 years, and cost approximately 2% of US GDP over that concomitant period; when the US produced more than a third of World Output, the highest share of any economy in modern Economic History. Currently NASA's space budget is a paltry 0.1% of annual GDP. To an economist, the gains of Space Exploration are uncertain and unquantifiable. More so if there are any perceivable side benefits they would be spaced over many generations. Inherently, like defence expenditure, street lighting, and welfare benefits, space exploration is a public good. In that its supply cannot be excluded to the beneficiaries of any one country and, if left to the initiative of private agents, would be considerably under-supplied. The Great Age of Discovery was similarly laden with these characteristics, but the accidental sighting of the New World brought untold possibilities of plunder and power for European states within a matter of years. And that is the Heart of the Matter.
Like all Public Goods, only governments are able to supply them. Space Exploration [let alone possible Colonisation], with the current set of technology, takes time. Longer than the lifespans of political regimes and our current generation. A manned mission to Mars would cost around the same as the Apollo program; the International Space Station (ISS), a zero-gravity Lab, is nothing more than a $150 Billion White Elephant due to the opportunity cost of its construction and maintanence; Cost of Future Moon bases for purposes of heavy metal extraction or energy generation would be measured in Trillions, with perceivable benefits not obtainable through current level of Technology.
Much of the ongoing empirical and theoretical advancements in Physics and Astronomy have been made not through the ISS, Martian Space Probes, or Manned Shuttle/Soyuz Missions, but through orbital telescopes [Hubble, Planck and Chandra], Particle Labs like CERN and the Fermilab, and the innumerable scientific research institutes around the world. Given the reluctance of Governments to spend their kitties on intergenerational public goods, the Final Frontier lies in achieving a thorough understanding of the Cosmos whilst still on Earth.
Beijing already has its eyes set on achieving, like the USSR of old, its honours as a World Power through costly manned missions; and unlike India's space program, China's is bent with an entirely political agenda. However, Space Exploration and eventual habitation of Second Earths would require more than superpower rivalries. Only through the sense and sensibility of a benevolent World Government, Cost-effective Engineering and Technological solutions, and an advanced knowledge of Man's self-defined purpose, will their be consensual movement towards Space Exploration. All three which are sadly amiss in our times.
Gene Roddenberry, inventor of Star Trek, conquered the vast distances of Space through a science fiction device called the 'Warp Drive'; in which one could traverse those mileages without going into the nitty gritty of Time Dilation and other mathematical foibles that come with interstellar travel. Such science fiction tales are just tales. In reality and on hindsight, the Apollo program was an historical blur, that in the full span of Economic History and path dependent evolution of Civilisations, would have possibly occurred in a generation from now; when it could be economically, socially and technologically feasible. Our current generation's duty is to ensure the sustainability of our planet for the welfare of future generations.
Indeed without eliminating poverty, famine and warfare at home, it is unlikely any nation or world government will ever find it wise to boldly go where no man has gone before.