Future of our planet and human civilization has been among the most popular subjects of discussions over the last several decades. Escalating military conflicts and the appearance of deadly WMDs have led many to accept the theory of instability of our existence. Also contributing to the probability of gloomy variants of our future is asteroidal threat and threat coming from cosmic radiation emissions. Earth's history contains quite a number of environmental catastrophes that led to mass extinction of living beings on the planet. Religions predicted apocalypse to come yet thousands of years ago. First, they expected it to occur at the end of the first millennium AD and then they had timed it to various dates and events. Hundreds of books, articles, films and TV shows have appeared over the last 50 years alleging the possibility of a global cataclysm coming soon.

In this article we try to consider a different scenario for the future, an optimistic one, and to speculate about what humanity could achieve in the near future provided that we manage to overcome natural threats and avoid catastrophic military conflicts. To begin with, let's note that demographic situation on the planet may change in the near future with birth rate falling down to 1.2-1.5 children per family as it presently occurs in a number of developed countries. A trend can be traced that the higher the quality of life the lower the birth rate; quality of life tends to increase in many countries now, albeit slowly. Important question to ask is whether mankind succeeds at stopping the growth of the world population at the threshold of 9-10 billion people before it is too late. Afterwards, world population can be forecast to reduce, probably down to a level allowing for such vital provisions as food, water, living accommodation, medical care and education to be arranged much more easily and effectively. Technological progress, that has been particularly rapid since the last century, serves to accelerate and simplify the production of food, clothing, housings, transport, etc. The trends that have taken shape nowadays have the potential of leading to the reduction of the world population down to several billions of people over the lifetime of the next 5-7 generations. It may be true to say that the next several decades will represent the most critical time for humanity, and, if we manage to survive, will be followed by a period characterized by a noticeable decline in the world population.

It is widely believed that the principal issue for any civilization is availability (sufficiency) of resources for the production of energy and food, metals, fresh water and areas suitable for living where natural disasters are seldom or rare. I will dare say that this is untrue. There is a solution to this problem, it is accessible, we only need to join efforts to take it. All what we need is to open our eyes wider to acknowledge the fact that we do not have to be confined to the small space offered to us by this planet. We do have a very real opportunity to open the door into unlimited sunlit expanses with immense resources. As you have probably guessed, I'm speaking about the outer space, first of all its areas in the Earth's immediate neighborhood. Now, after half a century of cosmic era, mankind only needs to walk a few steps more to access these immense resources. The Moon and the Asteroid Belt contain much more metals and minerals than the accessible surface layer of the Earth. Apparently, at one moment in the future it will become simpler and cheaper to go to outer space assembling production facilities and living accommodations than to dig deeper and deeper into the Earth. Here it is appropriate to recall the famous words of the pioneer of astronautics, Konstantin Tsiolkovsky: "The Earth is the cradle of the mind, but we cannot live forever in a cradle."

Incidentally, the Earth receives less than one-millionth of the energy irradiated by the Sun, and we are using a negligibly small fraction of it. With the progress in solar cell technology, we may become capable of generating almost unlimited amounts of electricity by installing solar cells beyond the Earth's atmosphere. The Japanese plan to commission their first pilot space-based power plant in 2020. And no less challenging problem will be energy transmission back to Earth. Variants for energy transmittal are being considered, including in the form of non-ionizing microwave radiation.

There are reasons to expect a breakthrough in the field of "space industrialization" by the middle of this century. Probably, manned facilities will appear on the Moon and production of useful mineral will be started there and, probably, in the asteroid belt. Incidentally, in 2003, a robotic spacecraft had soft-landed on asteroid Eros which is only 33 kilometers long. The spacecraft took samples from the asteroid surface and brought them back to Earth. In all likelihood, it will be possible to find asteroids rich in various useful materials and to use these materials in space-based production. I dare to say it will be not a very distant future when it becomes economically beneficial to manufacture assembly parts of space stations at production facilities located outside of the Earth – on the Moon or on artificial satellites. This will allow saving on fuel that would otherwise be spent on overcoming the Earth's gravity. Robotic (or minimally manned) factories will produce equipment needed for the construction of space-based industrial facilities, space settlements and living amenities. However, first it will be necessary to perform quite a challenging work of establishing a first production facility outside of the Earth. After this task is accomplished, the facility could be used as a vehicle to accelerate space-based construction.

Outer space and its resources can be developed at a rather high tempo. Recall the rapid progress of space exploration in the second half of the 20^th century. Suffice is to say that over the 12 years from 1957 when the first artificial satellite weighing only 83 kilos was launched, the weight or artificial satellites grew to over 120 tons. In fact, there is nothing unusual or surprising in a thousand- or million-fold improvement in performance of innovative technical appliances over a decade or several decades. Incidentally, growth of that pace was recorded in fissile isotope production, in computer science and technology, not to mention bombs. Recall how the first airplane in 1903 could fly only several hundred meters, and fifteen years later there were thousands of aircraft built that could fly long distances carrying considerable payloads. Everything depends on the extent of necessity, feasibility and the funds and resources allocated.

In my opinion, one of the biggest challenges facing our civilization is the development of innovative and more effective approaches to bringing payloads on orbit. Status as of today, the weight of satellites put into orbit equals only few percent of the rocket's takeoff weight. In addition to being fuel-extravagant and poorly cost-effective, this method of putting payloads on orbit is associated with unacceptable atmospheric pollution, not to mention the danger of "sitting" on hundreds or even thousands of tons of flammable matter.

Alternatively, we can consider options where only payload and the last 1-2 stages of the rocket are accelerated. Such a system could, for example, be set up in a long (several kilometers in length), partially evacuated tunnel somewhere in the mountains [1]. This would allow shortening the interval between launches to several hours or even minutes. (With present-day launch pads, it takes a lot of time to get prepared for a next launch). Jules Verne novel From the Earth to the Moon was an exceptional insight. It is interesting to note that the possibility of achieving escape velocity with the help of cannon was raised by Isaac Newton. In the first half of the 20^th century designs were made of guns to launch "projectiles" looking like rockets with one or several stages. Several years ago American engineers discussed the idea of accelerating a 3-ton platform in a 3-kilometer long tunnel using compressed hydrogen. Frequently appearing nowadays are reports featuring various kinds of catapults and railguns [2] used for spacecraft accelerating [3], [4] or for military applications. Possibly, such systems could potentially be most useful for cargo spaceships since that high acceleration loads could be intolerable for human beings. There is a variant where additional acceleration is provided by on-board propulsion engines, such as a supersonic combustion ramjet supersonic in-built (which, unlike a rocket engine, takes oxidizer from air and, therefore, weighs less). Small-scale pilot rail-guns already exist in a number of space centers in the United States. According to recent reports, projectile speed of over 3,500 meters per second was achieved at one of the NASA pilot railguns [5].

Here it is appropriate to recall how particle accelerators accelerate dense electron flows to nearly the speed of light with useful efficiency of up to 95% (!). (Both impulse and stationary flows with power output of hundreds of kilowatts; there are ways to increase power output to several gigawatts) [6]. Of course, these are absolutely different apparatuses. Electrons are charged particles and they are accelerated by an electric field. But that was a challenging problem too and it took scientists decades to overcome. Successful experiments have also been performed to accelerate (with high useful efficiency) thousand times heavier particles – ions [7]. The creation of apparatuses that demonstrate fundamentally better performance and useful efficiency close to ultimate inspire researchers into looking for radically innovative space launch solutions.

It is quite understandable why no active work has so far been performed aimed at building monumental engineering structures for non-rocket pre-acceleration of massive objects. Explanation is very simple: Overwhelming majority of specialists in the field is involved primarily in military research and development. For military purposes, it is highly desirable for each rocket to be deployed separately and for some of them to change their location from time to time. It is open secret that space breakthroughs have been byproducts of military programs and hence have been achieved at relatively low cost. If we set the task of developing an effective method for transporting cargoes to orbit as priority, we are likely to obtain results in reasonable time. This approach is well in line with the pressing need to stop arms race and turn to other tasks that are more important for the existence of the human civilization.

Also deserving to be noted here is another alternative – that of using special aircraft, like American SpaceShipOne, for pre-acceleration of space apparatuses. The latter program has reported success recently. The cost of short-time pleasure trip to orbit will become affordable and thousands of people will be on the waiting list. It is reasonable to forecast that regular "tourist" flights to orbit will begin already in the near future. Media reports appear from time to time about prospects for nanotechnology to create materials that are 50-100 times stronger than currently existing ones. With such materials available, it will become possible to bring to life another fantastic project – Space Elevator [8].

Speaking of more distant future, it is possible to imaging the construction of space-based cities and probably flights to other constellations. Already being discussed today is the possibility of giving Mars artificial atmosphere, using "space sails" for distant space travel, nuclear-propelled rockets, etc. It is difficult to foresee what discoveries and prospects are behind the corner. Of course, most of what was mentioned above will be possible only provided that mankind manages to stop vehement conflicts instead of expanding them into the outer space.

Among forecasts for even more distant future, I would like to mention transformation of the human body and brain and artificial intelligence. I mean robots, cyborgs and genetically modified people. A promising direction in this field is the construction of lightweight and highly intelligent robots capable of performing sophisticated jobs without human involvement. It is well known that research in this direction is rather intensive and, in addition to "conventional" robots, ultraminiature "nanorobots" may probably be created.

The appearance of artificial intelligence (if it ever comes) will help resolve many of the present-day pressing problems, such as environmental protection. Artificial apparatuses (beings?) will not only be more efficient in preserving the environment, but will be able to exist in a wider range of ambient conditions. Here it is appropriate to note that there exists a theory that the present stage of mind's evolution is only a preliminary, embryonic, stage; on subsequent stages, the human mind will become fundamentally modified, will break free into outer space to conquer faraway worlds.

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[1] See the author's book at http://www.savefuture.ru/files/2009edition.pdf; http://www.savefuture.net/files/2009edition-en.pdf (Chapter 17)

[2] See Artsimovich's railgun

[3] See, for example, http://www.inright.ru/news/id_4035/

[4] A talented engineer, Gerald Bull, attempted to build a cannon with a 156-meter long barrel with firing range of around 1,000 km. He happened to be doing his work in Iraq, got killed and the project was stopped. Bull's cannon was expected to put satellites weighing up to 200 kilos on orbit.

[5] Emerging Technologies May Fuel Revolutionary Launcher - NASA, September 10, 2010.

[6] See author's book "Intense Electron Beams" (in Russian), Energoatomizdat, 1984.

[7] E. Abramyan, V. Vecheslavov: "Acceleration of Intense Proton Beam on a Transformer Type Apparatus," (In Russian), Atomic Energy, Vol. 22, Issue 5, 1967.

[8] See Space Elevator.