Terraforming the planets of the solar system (beginning). Terraforming The most important tasks of terraforming scientists

The practical significance of terraforming is the need for the Earth's population to continue its reproduction and settlement. At the same time, over time and a sharp increase in the population, there is a need to remove territorial restrictions for further existence and development. To a certain extent, such a desire can also be stimulated by the expansion of the parent star (the sun) and the emergence of a threat to the existence of life. As the habitable zone expands and shifts to the periphery of the solar system, life will tend to move to more comfortable conditions.
In addition to natural factors, the consequences of the activities of humanity itself can also play a significant role: the economic or geopolitical situation on the planet; global catastrophe caused by the use of weapons of mass destruction; depletion of the planet's natural resources, etc.

The possibility of relocation to extraterrestrial colonies may, over time, lead to the formation of cultural traditions where the relocation of people to colonies will continue continuously for many generations. Cultural traditions can be changed by medical advances, which can lead to significant extensions of human life. This, in turn, can lead to a “conflict of generations”, when representatives of younger generations and older ones begin to fight among themselves for vital resources. In general, the possibility of resolving political conflicts by emigrating dissidents to colonies can significantly change the political structure of many democratic states. In this case, the process of creating new colonies will be similar to the process of building “elite” microdistricts, when colonies are created by commercial structures in the hope of recoupment; or, conversely, the construction of public housing for the poor to reduce crime in slums and reduce the influence of political opposition in them. Sooner or later, the “real estate” in the Solar System will be divided and the process of relocation will not be limited to the planetary objects existing in the Solar System, but will be directed towards other star systems. The question of the feasibility of such projects depends on manufacturability and the allocation of sufficient resources. As with any other super-projects (such as the construction of huge hydroelectric power plants or railways “from sea to sea”, or, say, the Panama Canal), the risk and size of the investment are too great for one organization and will most likely require the intervention of government agencies and attracting appropriate investments. The implementation time for projects to terraform near-Earth space can, at best, be measured in decades or even centuries.

Criteria for the suitability of planets for terraforming

Not every planet is suitable for terraforming. At the moment, based on the scientific data obtained, it is believed that the planets that are categorically unsuitable for human habitation are the giant planets, and primarily Jupiter and Saturn. The unsuitability of these planets is due to ultra-high gravity, the absence of a solid surface, and high temperatures at the lower boundary of the atmosphere, as well as high background radiation. In the Solar System, the most suitable conditions for supporting life for 1-2.5 billion years in the case of terraforming are primarily possessed by Mars, then to a lesser extent (300-500 million years) by Venus. The remaining planets are either completely unsuitable for terraforming, or face almost unlimited difficulties in transforming their climatic conditions. For example, Mercury can also be terraformed, but the period of existence of acceptable conditions for living organisms cannot exceed 10-30 million years, and only at the poles. Naturally, the suitability of planets for terraforming depends on the physical conditions in which these planets are located. The main ones of these conditions are:

• Gravity on the planet's surface: It is quite obvious that the gravity of the planet being terraformed must be sufficient to maintain the desired atmosphere with the appropriate gas composition and humidity. In this aspect, planets that are too small in size and mass are completely unsuitable, since there will be a significant leak of the atmosphere into outer space. On the other hand, the necessary degree of attraction is necessary for the normal existence of living organisms on the planet, their reproduction and sustainable development.
• Amount of solar energy received: a sufficient amount of solar energy to warm the surface and atmosphere of the planet is absolutely necessary for carrying out work on terraforming planets. First of all, the planet’s illumination by the Sun (as well as any other parent star) must be sufficient to warm the planet’s atmosphere, at least under conditions of an artificial greenhouse effect, to maintain temperatures on the surface sufficient for the stable presence of water in a liquid state. On the other hand, illumination is necessary for the reproduction of energy using photo- or thermal converters for the needs of the planet's population and (in the future) for performing terroforming tasks. When viewed from the illumination point of view, it is clearly visible that the zone in which there is the necessary amount of solar energy and in which suitable planets can be located barely reaches the orbit of Saturn, and therefore terroforming in deeper regions of space is currently impossible. At the same time, in the future, with the expansion of the Sun, the level of energy sufficient for short-term (several hundred million years) maintenance will be within the orbit of Pluto or even in the near regions of the Kuiper Belt.
• Availability of water: the amount of water necessary to maintain the population of the planet with animals and plants is one of the constant conditions for the possibility of settlement and successful terraforming of a particular planet. It is important to note that there are not many worlds in the solar system that have sufficient volumes of water, and in this regard, besides Earth, only Mars and the moons of Jupiter can be mentioned: Europa, Ganymede and Callisto. The question of the presence of water on Titan still remains open. In other cases, water must be brought to the planets using technical means.
• Radiation background: On the planet undergoing terraforming, there must be an acceptable level of radiation, that is, a low general background of cosmic radiation, the level of radioactive radiation from rocks. In general, during terraforming, and accordingly creating an atmosphere of the required power, natural attenuation mechanisms are activated - the absorption of radiation by the atmosphere itself and, in particular, the absorption of ultraviolet radiation by ozone. If a planetary satellite is subjected to terraforming, it is important that it be located outside its radiation belts. Natural radiation from rocks can present a significant obstacle to the development of a planet, but most often the level of planetary radiation is quite acceptable.
• Asteroid situation: low probability of the terraforming planet being hit by large asteroids. In a solar system where the asteroid situation differs from ours for the worse, that is, where the asteroid belt is dangerously close to the proposed settlement site, the surface of an Earth-like planet may be at risk of frequent encounters with asteroids, which can cause significant damage to the surface of the planet.

Prospects for terraforming solar system objects

Paraterraforming

Project Eden (UK)

Biosphere-2 (inside)

An intermediate step between a planetary station and terraforming could be “Biosphere 2”, that is, a huge artificial biosphere. In principle, such a greenhouse-biosphere can be the size of the entire planet, especially if the planet has weak gravity and is not able to retain its atmosphere. The problem of cooling the atmosphere can be solved in the same way. After all, the inner surface of the greenhouse can be covered with a mycoscopically thin layer of aluminum that reflects infrared radiation. In this version of terraforming, colonists have the opportunity to live in comfortable conditions almost immediately after arriving on the planet, since the protective dome can be made of such light material that it can fit in one transport ship of an acceptable size. The dome can be made of a soft material and maintain its shape due to internal pressure (which of course means that this option will not be suitable for the colonization of Venus or any other planet with a significantly thick atmosphere. With a dome roof height of several kilometers, the climate inside such a biosphere will be similar to Earth's and can be controlled to create the complete illusion of being on a terraformed planet.

Prospects for terraforming planets and satellites of the solar system

Mars

The first phase of terraforming Mars

The second phase of terraforming Mars

The third phase of terraforming Mars

The fourth phase of terraforming Mars

Red and inhospitable Mars, named after the god of war, has been attracting the gaze of all mankind for millennia. A strange irony - a planet of deserts and giant volcanoes, a planet with a harsh name, and a planet whose planet is historically destined to become our second home. Mars is the most suitable candidate for terraformation (surface area ~ 144.8 million km 2, which is equal to 28.4% of the Earth's surface). The acceleration of gravity on the surface of Mars is 3.72 m/s 2 , and the level of solar energy perceived by Mars is 43% of the level received by the surface of the Earth. Currently, Mars, according to research, is a lifeless (probably) planet, more like the Moon than the Earth. At the same time, the amount of information obtained about Mars suggests that once the natural conditions on it were favorable for the maintenance and possible origin of life. Mars has huge amounts of water ice and bears on its surface numerous traces of its favorable climate in the past (river valleys, shallow beaches, clay deposits and much more). Many modern scientists are confident that it is possible to heat the planet and create a more or less dense atmosphere on it, and NASA even conducts pseudo-scientific discussions on this matter. However, there are undoubted difficulties in this direction that prevent terraforming Mars or any other planet at the present time. The gigantic reserves of water and bound oxygen in the composition of peroxides and ozonides in the soil of Mars give strong grounds to assume that by influencing the Martian climate, terraforming of this planet will become quite possible. In this direction, enormous efforts of all mankind are needed, and already at the present time it is quite possible to organize financial and technical formations (clubs, societies and companies) on Earth intended for the development and future changes in the climatic conditions of Mars. Currently, earthlings have mastered the use of nuclear energy very well, but important problems related to the transportation of energy equipment to Mars and its maintenance on the planet itself still remain unresolved. At the same time, Mars itself has very significant metal resources, including nuclear fuel resources (uranium, thorium), and when setting up industry on Mars and significant use of nuclear fuel, accordingly, a colossal amount of waste heat is expected to be released into the Martian atmosphere. One of the most important technological obstacles to the exploration of not only Mars, but also other planets is the fact that currently the capabilities of space vehicles are too limited, and in this regard, great hopes are placed on gas-phase nuclear rocket engines and, in the future, thermonuclear rocket engines. Only if there are nuclear rocket engines with colossal thrust-to-weight ratio, reliability and speed, will it become entirely possible to deliver heavy loads intended for the initial stage of terroforming to Mars, and in the future even asteroids made of water-ammonia ice intended to fill the atmosphere and hydrosphere of Mars with nitrogen, water and oxygen. Presumably, asteroids can be transported from the asteroid belt and even from the Kuiper belt using rockets or solar sails. Terraforming of Mars can occur both with the direct introduction of artificially produced greenhouse gases (freons) into its atmosphere, and with the heating of the planet's surface using solar radiation directed by orbital mirrors and darkening the surface of the polar caps with soot or polymer films, and indirectly with the development of Mars and its minerals (metallurgy, mining blasting, etc.). Both processes can occur simultaneously and make a major contribution to climate change on Mars. For example, the development of large-scale nuclear and, in the future, thermonuclear energy will make it possible, one way or another, to release huge volumes of secondary heat in the atmosphere, and in the future, in the hydrosphere of Mars. So, for example, it is quite obvious that when setting up large-scale energy and producing hydrogen and oxygen for ground Martian transport, spacecraft and power supply to settlements, conditions will arise for the release of large volumes of thermal energy in the atmosphere. Taken together, the total amount of energy will heat the atmosphere of Mars, and contribute to a significant greenhouse effect when the polar caps melt.

Asteroid impact on the surface of Mars (artist's fantasy)

Space mirror in orbit of Mars

• Release of artificial greenhouse gases into the Martian atmosphere: tetrafluoromethane, octofluoropropane.
• Darkening the surface of the polar ice caps: soot, sprayed polymer films, explosive albedo reduction.
• Orbital heating of the polar surface: space ultra-light orbital mirrors.
• Asteroid bombing: water-ammonia ices.
• Technogenic activity: heat emissions from nuclear power plants and transport, heat flows from dome settlements.
• Biogenic impact: introduction of terrestrial bacteria and algae resistant to Mars ( Chroococcidiopsis sp, Matteia sp, Deinococcus radiodurans, etc.).

Venus

Terraformed Venus

For thousands of years, the beautiful morning star Venus has attracted the consciousness of people and, for her beautiful brilliance, received the name of the goddess of beauty. Later, people learned that the outwardly beautiful planet was lifeless, and instead of, as expected, an ocean on the surface, it was a hellish furnace with monstrous atmospheric pressure on the surface. Nevertheless, it is considered by scientists as a likely candidate for terraforming - (surface area ~ 460 million km 2 (90.18% of the Earth's area) which is close to the Earth's at 510.073 million km²). The acceleration of gravity on the surface of Venus is 8.9 m/s 2 . The solar constant on the surface of Venus is ~2613.9 W*m2. According to one of the plans, it was supposed to spray genetically modified blue-green algae into the atmosphere of Venus, which, by processing carbon dioxide (the atmosphere of Venus is 96% carbon dioxide) into oxygen, would significantly reduce the greenhouse effect and significantly lower the temperature on the planet, which would allow would be the existence of water in liquid form. It should be noted that at an altitude of ~ 50-100 km in the atmosphere of Venus, there are conditions under which some terrestrial bacteria can exist. Another option is to spray aluminum powder in Venusian orbit, delivered in containers using an electromagnetic gun from the Moon.

Terraformed Venus without clouds (in the center is the continent of Aphrodite)

In itself, the terraforming of Venus is justified by the fact that the planet is not only very close in characteristics to the earth, but also by the fact that by processing the atmosphere of Venus for one to two thousand years, it will be able to support the existence of life for hundreds of millions of years until the radiation of the sun will become an insurmountable barrier to its existence. The size and topography of Venus allow, under appropriate conditions, to carry on its surface huge oceans of water and large areas of land inhabited by animals and people. Compared to the volume of tasks of terraforming Mars, terraforming Venus is an order of magnitude more complex task, but if there is a sufficient amount of information about the planet and solid energy resources, this task is feasible. First of all, Venus is significantly different from the earth in that its daily rotation and axis tilt make it completely difficult to transform its natural conditions, but with the precise bombardment of its surface by icy asteroids of sufficient size, these parameters can be changed within several decades. At the same time, the bombardment of Venus by asteroids made of water-ammonia ice allows not only to change the rotation parameters and, by establishing a change of seasons, allow the planet to cool greatly, but also to cool the planet and its atmosphere due to the melting and evaporation of asteroid materials. Borrowing enormous energy from the atmosphere can occur due to the parallel occurrence of chemical reactions between carbon dioxide and sulfur dioxide in the atmosphere and ammonia.

The main methods of terraforming Venus:

• Asteroid bombing: water-ammonia ices..
• Biogenic impact: introduction of terrestrial bacteria and algae stable in the upper atmosphere of Venus: ( Pyrodictium occultum, Halobacterium salinarum, etc.).

Europa (moon of Jupiter)

Jupiter rising over the ocean of terraformed Europa (artist's fantasy)

Europe is potentially promising for teraforming. The surface area of ​​Europa is about 31 million km2, slightly smaller than the surface area of ​​the Moon (37.9 million km2). The acceleration of gravity on the surface of Europa is 1.3 m/s 2 , and the level of solar energy perceived by Europa at the present time is about ~50.5 W/m 2 . One of the interesting and important advantages of Europe over many other planets is the presence of a gigantic amount of liquid water. By right, Europe is an ocean planet. This could be quite useful for introducing complex life. The challenges to terroforming are numerous. For example, Europa is located in a huge and powerful radiation belt around Jupiter, and a person without protective equipment would die from radiation after 10-15 minutes of being on the surface of Europa. This circumstance requires the creation of huge radiation absorbers, which is currently impossible, or the movement of living beings under the surface of Europa's ocean. This satellite can be heated and used to supply oxygen and hydrogen. A significant disadvantage of Europa for full-scale terraforming is the low gravity of this planet, which is unable to maintain a sufficiently powerful atmosphere for a long time (billions of years).

Titan (saturn's moon)

Multispectral image of Titan (bright area - continent of Xanadu)

Terraforming of Saturn's satellite Titan is a very distant prospect, and to a large extent this is facilitated by its significant distance from the sun (the Solar constant on Titan is ~15.04 W/m2). Titan is a fairly large body of the solar system and is larger in size than the planet Mercury (Titan's surface area is ~ 83 million km 2). The acceleration of gravity on Titan is 1.36 m/s 2 . At the same time, Titan, due to the natural conditions prevailing on it, and in particular the absence of a greenhouse effect on it and the strong reflection of solar energy by the atmosphere, is largely cooled. It is estimated that in the absence of reflection of solar energy, the atmosphere of titanium would be “warmer” by 80 K and the temperature conditions would correspond to the current conditions on Mars, and in the presence of the greenhouse effect it could be much more comfortable for people to live in special settlements on its surface. Titan is of interest to modern humanity for its significant natural hydrocarbon resources.

Future Titan (artist's fantasy)

The oceans, seas and lakes, composed primarily of liquid ethane, represent enormous wealth. Since the acceleration of gravity and, accordingly, the second cosmic velocity are small, the production of hydrocarbons in the future will be much easier than even oil production on Earth, and what is especially valuable is that hydrocarbon raw materials can be simply pumped out of Titan’s reservoirs. Increased extraction of raw materials and their removal from the planet will simultaneously dramatically reduce the volume of hydrocarbon smog in Titan’s atmosphere and increase its transparency and heating by solar rays. Considering this process, it is worth noting that the consumption of hydrocarbon raw materials on earth (oil, gas, coal) already exceeds 6-7 billion tons per year and the need for it is growing, and pumping such a volume of hydrocarbons from the surface of Titan will significantly affect its climate. It is also possible that hydrocarbon raw materials will be needed in the future to supply not only the earth, but also colonies on the Moon, Mars and Venus. Titan is also very interesting because it apparently contains huge quantities of liquid acetylene and mixtures of acetylene with ethane. Acetylene is a highly endothermic compound (54 kcal/mol (~2090 kcal/kg)) and could serve as a huge energy source for Titan's future industry. It is also very important that over the course of 3-4 billion years, large-scale photolysis of hydrocarbons took place in Titan’s atmosphere and most of the hydrogen went into space, and deuterium, as a heavier isotope, accumulated on the surface of Titan, and can serve as a huge reservoir of fuel for thermonuclear energy as on Titan itself and as an export product to the inner solar system.

Terraformed Moon (artist's fantasy)

The surface area of ​​the Moon is 37.9 million km 2 (more than the area of ​​Africa), and the acceleration of gravity on the surface is 1.62 m/s 2 . The Moon is the natural satellite of the Earth and the closest planet to the Earth, and the possibilities for its terraforming are quite large in the foreseeable future. The Moon is capable of maintaining a more or less dense atmosphere, but due to low gravity, such an atmosphere, even consisting of dense gases (water vapor, oxygen, nitrogen, carbon dioxide and argon) will dissipate quite quickly (within hundreds of millions of years) in outer space. Approximate calculations of the speed of gas molecules when heated to, for example, 25-30°C turn out to be within several hundred meters per second, and at the same time, the second cosmic speed on the Moon is about 2 km/sec, which allows us to hope for a long-term retention of an artificially created atmosphere on it. It is likely that, once created, the atmosphere from imported materials (water-gas ice of asteroids) will have to be replenished by the constant import of new materials. On the other hand, the exploration and settlement of the Moon at the current technological level of technology development is possible precisely in the aspect of building isolated domed settlements.
Of great importance when terraforming the Moon by bombarding its surface with icy asteroids is the safety of such bombardment. Since such a process will have to be carried out in close proximity to the Earth, there is a possibility of emergency situations and threats to the Earth itself. The impact of a large asteroid on the surface of the Earth can cause great damage to the existence of its life. Obviously, the bombardment of the Moon should be “soft”, that is, the material for bombardment should not be very large (blocks several hundred meters in diameter), impacts on the surface should be from the orbit of an artificial satellite of the moon, such attacks should be strictly calculated using powerful computers and is carried out along a tangential trajectory to the surface of the Moon, directed away from the Earth. It is also likely that earthlings will need to give the Moon a daily rotation and change the tilt of its axis to ensure the change of seasons, but today it is not yet clear what consequences such rotation will cause in relation to the tectonics of the Earth’s plates and global volcanism of both bodies of the system.
In addition to directly bombarding the lunar surface with icy asteroids, there is another way to create its atmosphere. As in the first case, icy asteroids with a diameter of 10 to 100 meters are towed to the Moon and placed into low lunar orbit. In this case, asteroids are launched by several intersecting streams coaxially with the polar axis of the Moon. Asteroids placed in this way will constantly experience collisions with each other and intensively fragment. Since their orbits will be quite low, small ice crystals and gas will enter the lunar gravity zone and form an equatorial atmospheric ring that will spread over the surface of the Moon. If the Moon has a primary atmosphere, the subsequent discharge of meteoric material will occur “softer”, and in the artificial atmosphere of the Moon, icy asteroids will evaporate faster.

The main methods of terraforming the Moon:

• Asteroid bombing: water-ammonia ices.
• Biogenic impact: introduction of terrestrial bacteria and algae that are stable in the primary artificial atmosphere of the Moon and under solar radiation conditions.

Despite Although, according to many scientists, the Moon is the most attractive space object for potential colonization, at the initial stage of such a project, preliminary terraforming of the satellite will still be required. Methods of terraforming in each specific case are determined depending on factors such as the size of the cosmic body, the presence of an atmosphere, gravity, magnetic field, as well as the basic elements necessary for the origin and maintenance of life.

So, as for the Moon, the surface area of ​​​​the satellite is slightly larger than the area of ​​​​Africa. The Moon has weak gravity, which does not allow the satellite to maintain a dense atmosphere. The gravitational acceleration here is 1.62 m/s2. Even if you try to artificially create an atmosphere on the Moon using imported materials, the satellite is unlikely to be able to maintain it. At best, the state of the atmosphere will need to be constantly maintained through additional imports of materials. Therefore, at this stage, scientists are currently only considering the possibility of creating isolated domed settlements - closed ecological systems.

However, let us return to the plans for terraforming the satellite. As noted above, the first stage of terraforming is creating an atmosphere. To achieve this goal, scientists propose a method of bombarding the lunar surface with icy asteroids. However, due to the close proximity of the Earth, such a bombardment could pose a threat to our planet, so this method requires very accurate calculations, as well as analysis of possible emergency situations. Based on this, we can now firmly state that these should not be very large asteroids with a diameter of no more than several hundred meters, and the bombardment itself should be carried out along a tangential trajectory to the surface, directed away from the planet.

However, according to some experts, to create an atmosphere it is not at all necessary to carry out bombardment; it is enough to place asteroids in low lunar orbit in such a way that the asteroids constantly collide with each other and are crushed. In this case, it is expected that small ice crystals will fall into the lunar gravity zone and create an equatorial atmospheric ring, which will eventually spread over the entire surface. Thus, a primary atmosphere will be created, under which conditions one can even resort to the method of asteroid bombardment, which will now take place much more softly.

Scientists are also theoretically considering the possibility of changing the tilt of the Moon’s axis to ensure the change of seasons on the satellite, as well as giving it a daily rotation (at the moment, a day on the satellite lasts 28 Earth days).

The second stage of terraforming the satellite may involve populating the surface with terrestrial bacteria and algae that would be stable enough to survive in the conditions of the primary atmosphere and solar radiation.

It is worth noting that many are critical of the potential colonization of the Moon, stating that Mars (despite its remoteness) is a more attractive object. Unfavorable factors that can greatly interfere with the implementation of the plan are the lunar day, which is of little use for supporting plant life, strong solar radiation, significant changes in daily temperatures, and so on. However, scientists continue to develop a plan to develop the satellite. The main stimulus for them is helium-3 (a rare isotope used in thermonuclear fusion plants), which is found in large quantities in the soils of the Moon.

Terraforming is a change in the climatic conditions of a planet, satellite or other cosmic body to bring the atmosphere, temperature and environmental conditions to a state suitable for habitation of terrestrial animals and plants. Today this problem is of mainly theoretical interest, but in the future it may be developed in practice.

The term "terraforming" was first coined by Jack Williamson in a science fiction story published in 1942 in Astounding Science Fiction, although the idea of ​​converting planets to Earth-like conditions had been present in earlier works by other science fiction writers.

The practical significance of terraforming is determined by the need to ensure the normal existence and development of humanity. Over time, the growth of the Earth's population, environmental and climatic changes can create a situation where the lack of suitable territory for habitation will threaten the continued existence and development of earthly civilization. Such a situation, for example, will be created by inevitable changes in the size and activity of the Sun, which will greatly change the living conditions on Earth. Therefore, humanity will naturally strive to move to a more comfortable zone.

In addition to natural factors, the consequences of the activities of humanity itself can also play a significant role: the economic or geopolitical situation on the planet; global catastrophe caused by the use of weapons of mass destruction; depletion of the planet's natural resources, etc.

The possibility of relocation to extraterrestrial colonies may, over time, lead to the formation of cultural traditions where the relocation of people to colonies will continue continuously for many generations. Cultural traditions can be changed by medical advances, which can lead to significant extensions of human life. This, in turn, can lead to a “conflict of generations”, when representatives of younger generations and older ones begin to fight among themselves for vital resources. In general, the possibility of resolving political conflicts by emigrating dissidents to colonies can significantly change the political structure of many democratic states. In this case, the process of creating new colonies will be similar to the process of building “elite” microdistricts, when colonies are created by commercial structures in the hope of recoupment; or, conversely, the construction of public housing for the poor to reduce crime in slums and reduce the influence of political opposition in them. Sooner or later, the “real estate” in the Solar System will be divided and the process of relocation will not be limited to the planetary objects existing in the Solar System, but will be directed towards other star systems. The question of the feasibility of such projects depends on manufacturability and the allocation of sufficient resources. As with any other super-projects (such as the construction of huge hydroelectric power plants or railways “from sea to sea”, or, say, the Panama Canal), the risk and size of the investment are too great for one organization and will most likely require the intervention of government agencies and attracting appropriate investments. The implementation time for projects to terraform near-Earth space can, at best, be measured in decades or even centuries.

Planets potentially suitable for immediate settlement can be divided into three main categories:

• - an inhabited planet (a planet like Earth), most suitable for settlement;
• - a biologically comparable planet, that is, a planet in a state similar to Earth billions of years ago.

Terraforming a planet that can easily be changed can be done at minimal cost. For example, a planet with a temperature exceeding the optimum for an Earth-type biosphere can be cooled by spraying dust into the atmosphere according to the “nuclear winter” principle. A planet with an insufficiently high temperature, on the contrary, can be heated by carrying out targeted nuclear strikes on hydrate deposits, which would lead to the release of greenhouse gases into the atmosphere.

Not every planet can be suitable not only for settlement, but also for terraforming. In the Solar System, at the moment, one of the planets that is not suitable for human settlement is Jupiter - due to high gravity (2.4 g) and high background radiation (when approaching Jupiter, Galileo received a radiation dose 25 times higher than lethal dose for humans). In the Solar System, Mars has the most suitable conditions for supporting life after terraforming. The remaining planets are either poorly suited for terraforming or encounter significant difficulties in transforming climatic conditions. For example, Mercury can be terraformed, but due to its close proximity to the Sun and the gradual expansion of the Sun, the period of existence of conditions acceptable for living organisms is too short.

The suitability of planets for terraforming depends on the physical conditions in which these planets are found. The main ones of these conditions are:

— Acceleration of free fall on the surface of the planet. The gravity of the terraformed planet must be sufficient to maintain an atmosphere with the appropriate gas composition and humidity. Planets that are too small in size and, therefore, in mass are completely unsuitable, since there will be a significant leakage of the atmosphere into outer space. In addition, a certain degree of attraction is necessary for the normal existence of living organisms on the planet, their reproduction and sustainable development. Too high gravity can also make the planet unsuitable for terraforming, due to the impossibility of a comfortable existence for people on it.

— The volume of solar energy received. To carry out work on terraforming planets, a sufficient amount of solar energy is required to warm the surface and atmosphere of the planet. First of all, the illumination of the planet by the Sun (as well as by any other parent star) must be sufficient to warm the planet’s atmosphere at least until an artificial greenhouse effect is achieved to maintain temperatures on the surface sufficient for the stable presence of water in a liquid state. Illumination is also necessary for energy reproduction using photo- or thermal converters and for performing terraforming tasks. In terms of illumination, the zone in which there is the necessary amount of solar energy and in which suitable planets are located reaches the orbit of Saturn, and therefore in deeper regions of space terraforming is currently impossible. At the same time, in the future, with the expansion of the Sun, a level of energy sufficient for short-term (several hundred million years) maintenance will be within the orbit of Pluto or even in the near regions of the Kuiper Belt.

— Availability of water. The amount of water necessary to support the population of the planet with plants and animals is one of the constant conditions for the possibility of settlement and successful terraforming. There are not many planets in the Solar System that have sufficient volumes of water, and in this regard, besides Earth, only Mars and the satellites of Jupiter can be mentioned: Europa, Ganymede and Callisto. The question of the presence of water on Titan still remains open. In other cases, water must be brought to the planets using technical means. Planets with excessive amounts of water may also be unsuitable for settlement for the reason that colonists will need to bring with them all the elements of the periodic table necessary for existence on such a planet, since all the minerals on such a planet are buried under several thousand kilometers of ice.

— Radiation background on the planet. It goes without saying that high levels of radiation are detrimental to all living beings, as well as to the possible development of artificial life. But promising developments in the field of nanotechnology and genetic engineering can significantly increase the limit of background radiation tolerated by living beings.

— Surface characteristics. It is obvious that on gas giant planets it is almost impossible to create a solid surface. The technological level for this must be an order of magnitude higher than for “defrosting” an earth-like planet by spraying soot over the surface. The same applies to a planet with ammonia glaciers several hundred kilometers deep or a planet with high volcanic activity. Problems associated with constant eruptions of molten rock, earthquakes, or tidal waves (similar to tsunamis on Earth) will also pose significant challenges to terraforming.

— The planet has a magnetic field. Recently, evidence has emerged that in the absence of a magnetic field, the solar wind actively interacts with the upper layers of the atmosphere. In this case, water molecules are split into hydrogen and hydroxyl. Hydrogen leaves the planet, which becomes completely dehydrated. A similar mechanism operates on Venus.

- Asteroid danger. In a planetary system where the asteroid situation differs from ours for the worse, that is, where the asteroid belt is dangerously close to the proposed settlement site, the planet may be at risk of frequent collisions with asteroids, which could cause significant damage to the surface of the planet and thereby return it to its previous state (before terraforming). This means that in such a system, terraformers will have to create means of “regulating asteroid motion,” which will require a fairly high technological level.

In 2005, a planetary system was discovered near a star in the Gliese 581 system, the main “attraction” of which is the first habitable zone exoplanet discovered by humanity (Gliese 581 c), i.e. possessing physical characteristics that make the exoplanet potentially habitable (in particular, for this planet, the acceleration of gravity is 1.6 g, the temperature is from -3 to +40 ° C, etc.). The star has four discovered exoplanets. The fourth planet - the closest to the star and the smallest in mass - was discovered on April 21, 2009. Its minimum mass is 1.9 Earth masses, its orbital period around the star is 3.15 days.

Preterraforming - an intermediate step between a planetary station and final terraforming, for example, the construction of a garden city, essentially a huge artificial biosphere. This kind of greenhouse-biosphere can cover the entire planet, especially in conditions of low gravity, in which the planet does not retain its own atmosphere around it. This technological solution also eliminates the problem of cooling the atmosphere: the inner surface of the greenhouse can be coated with a microscopically thin layer of aluminum that reflects infrared radiation. With this type of terraforming, colonists receive comfortable living conditions almost immediately upon arrival on the planet, since it is technologically not difficult to make a protective dome from light material so that it can be transported on one transport ship of an acceptable size. The dome can be made of soft material and maintain its shape due to internal pressure. However, when colonizing planets with a dense atmosphere (for example, Venus), this option is not applicable. (Under the conditions of Venus or a similar planet with a dense atmosphere, it is possible to create a giant dome-type settlement turned into a balloon, since the earth’s air, that is, a mixture of nitrogen with 21% oxygen, weighs lighter than the Venusian atmosphere, and the lifting force of the air in the atmosphere Venus is about 40% of the lifting force of helium.) With a dome roof height of several kilometers inside such a biosphere, the climate will be similar to that of Earth and can be controlled. Such a colony can be placed in a geological depression, such as a crater or valley, to place the base of the dome above the bottom of the depression. In modern large cities, the population density sometimes reaches 10,000 people/km². At the same time, there is space for parks, gardens, beaches and other recreational facilities that provide residents with the opportunity to relax. For a colony of a million people in size, it will be necessary to build a biosphere with a size of about 100 km², that is, a hemisphere with a diameter of 12 km and a weight (without guy wires, frame and other supporting devices) of 15 thousand tons or 15 kg per person (that is, less than hand luggage that can be carried airplane passengers). Undoubtedly, there will be a danger of depressurization of the system in such emergency situations as an asteroid fall, a spaceship crash, or a terrorist attack. In the event of hostilities, the surface of the dome will be the enemy's first target. This means that such a colony will be forced to spend significant resources on defense-type activities. One way or another, the concept of the biosphere is quite realistic, taking into account the development of modern technologies, and the question of the feasibility of the project depends on reducing the cost of delivering cargo to a “high” Earth orbit, which currently costs about $10,000 per kg.

Prospects for terraforming planets and satellites of the solar system:

- Moon

Moon is a natural satellite of the Earth and the closest natural object to the Earth, and in the foreseeable future the probability of its terraforming is quite high. The surface area of ​​the Moon is 37.9 million km² (larger than the area of ​​Africa), and the acceleration due to gravity on the surface is 1.62 m/s². The moon is capable of maintaining a relatively dense atmosphere, but due to low gravity, such an atmosphere, even consisting of dense gases (water vapor, oxygen, nitrogen, carbon dioxide and argon), will quickly (within tens of thousands of years) dissipate in outer space. However, the Moon will be better able to retain an artificially created atmosphere than, for example, Titan, due to the fact that its gravity is almost 20% greater than that of the latter. Approximate calculations of the speed of gas molecules when warming up, for example, to 25-30 °C turn out to be within several hundred meters per second, while at the same time the second escape velocity on the Moon is about 2 km/sec, which ensures long-term retention of an artificially created atmosphere (fall time atmospheric density is 2 times for air is about 10,000 years). It is likely that, once created, the atmosphere from imported materials will have to be constantly replenished. However, at the current technological level of technology development, the exploration and settlement of the Moon is possible, rather, along the path of building isolated domed settlements.

Of great importance when terraforming the Moon by bombarding its surface with asteroids is the safety of such bombardment. Since this process will be carried out in close proximity to the Earth, there is a possibility of emergency situations and threats to the Earth itself. The fall of a large asteroid to Earth can cause great damage to it. Therefore, the bombardment of the Moon must be “soft”, that is, the object - the “projectile” for bombardment must not be very large (an asteroid several hundred meters across), impacts on the surface must be carried out from the orbit of an artificial satellite of the Moon, the impact must be accurately calculated and be carried out along a tangent trajectory to the surface of the Moon, directed away from the Earth. It is also likely that it will be necessary to give the Moon a daily rotation and change the tilt of its axis to cause a change of seasons, but today it is not yet possible to fully calculate the consequences of such rotation in relation to the processes of Earth plate tectonics and global volcanism of both bodies of the system.

The main methods of terraforming the Moon: bombardment by asteroids - water-ammonia ice, biogenic impact - the introduction of terrestrial bacteria and algae, stable in the primary artificial atmosphere of the Moon and conditions of harsh solar radiation.

— Mars

Mars is also one of the most suitable candidates for terraforming (surface area is 144.8 million km², which is 28.4% of the Earth's surface). The acceleration due to gravity on the surface of Mars is 3.72 m/s², and the amount of solar energy received by the surface of Mars is 43% of the amount received by the surface of the Earth. At the moment, Mars is a possibly lifeless planet. At the same time, the amount of information obtained about Mars allows us to say that the natural conditions on it were once favorable for the maintenance and origin of life. Mars has significant amounts of water ice and bears on its surface numerous traces of its favorable climate in the past: dried up river valleys, clay deposits and much more. Many modern scientists agree that it is possible to heat the planet and create a relatively dense atmosphere on it, and NASA even conducts pseudo-scientific discussions on this matter.

Significant reserves of water and bound oxygen in the composition of peroxides and ozonides in the soil of Mars give strong grounds to assume that terraforming of this planet will become possible with a targeted impact on the Martian climate. At present, the earth's civilization has well mastered the use of nuclear energy, but problems associated with the transportation of technical equipment to Mars and its maintenance on the planet itself still remain unresolved. At the same time, Mars itself has very significant resources of metals and nuclear fuel (uranium, thorium). When establishing industry on Mars and the subsequent use of nuclear fuel, colossal emissions of heat into the planet’s atmosphere are expected.

One of the most important technological obstacles to the exploration of not only Mars, but also other planets is the limited capabilities of space vehicles, so great hopes are placed on gas-phase nuclear rocket engines. Only with the presence of nuclear rocket engines with significant thrust, reliability and speed, will it become entirely possible to deliver heavy loads intended for the initial stage of terraforming to the planets, and in the future even asteroids made of water-ammonia ice, intended to fill the atmosphere and hydrosphere of Mars with nitrogen, water and oxygen. Presumably, asteroids could be transported from the asteroid belt and even from the Kuiper belt using rocket engines or solar sails.

Terraforming of Mars can be carried out both by directly introducing artificially produced greenhouse gases (freons) into its atmosphere, and by heating the surface of the planet using solar radiation directed by orbital mirrors, and darkening the surface of the polar caps with soot or polymer films, and indirectly during the exploration of Mars and its mineral resources (metallurgy, mining blasting, etc.). Both processes can occur simultaneously and make a major contribution to climate change on Mars. For example, the development of large-scale nuclear, and in the future, thermonuclear energy will allow the release of huge volumes of secondary heat in the atmosphere and hydrosphere of Mars. For example, when setting up the production of hydrogen and oxygen for ground Martian transport, spacecraft and power supply to settlements, conditions will arise for the release of large volumes of thermal energy into the atmosphere. Taken together, the total amount of energy will heat the atmosphere of Mars, and contribute to a significant greenhouse effect as the polar ice caps melt.

The main methods of terraforming Mars:

• — filling the atmosphere of Mars with greenhouse gases: methane and other hydrocarbons delivered in large quantities from Titan can quickly increase the pressure and temperature on Mars to an acceptable level, and also serve as a source of the missing key elements (carbon, hydrogen) necessary for the full terraforming of Mars;
• — release of artificial greenhouse gases into the atmosphere of Mars: freons (tetrafluoromethane, octofluoropropane, etc.) have record greenhouse effect indicators, but these compounds are very expensive to produce;
• — darkening of the surface of the polar caps: soot, smog from hydrocarbons delivered from Titan, sprayed polymer films, explosive decrease in albedo;
• — warming up the polar caps: space ultra-light orbital mirrors;
• — bombardment by asteroids: water-ammonia ice can create oceans and an atmosphere with acceptable pressure on Mars;
• — technogenic activity: heat emissions from nuclear power plants and transport, heat flows from dome settlements;
• — biogenic impact: introduction of terrestrial bacteria and algae that are stable on Mars (Chroococcidiopsis sp., Matteia sp., Deinococcus radiodurans, etc.).

— Venus

Venus is a lifeless planet with an average surface temperature of about 464 °C and pressure 93 times that of Earth. However, it is considered a likely candidate for terraforming. The acceleration of gravity on the surface of Venus is 8.9 m/s². According to one of the plans, it is proposed to spray genetically modified blue-green algae into the atmosphere of Venus, which, by converting carbon dioxide into oxygen (the atmosphere of Venus is 96% carbon dioxide), would significantly reduce the greenhouse effect and temperature on the planet, which would allow water to exist in liquid form. It should be noted that at an altitude of 50-100 km in the atmosphere of Venus, there are conditions under which some terrestrial bacteria (Extremophiles) can live. Another option is to spray aluminum powder in Venusian orbit, delivered in containers using an electromagnetic gun from the Moon.

Compared to the volume of tasks of terraforming Mars, terraforming Venus is an order of magnitude more complex task, but if there is a sufficient amount of information about the planet and solid energy resources, this task is feasible. First of all, Venus is significantly different from Earth in that its daily rotation and axial tilt make it difficult to transform natural conditions, but with the precise bombardment of its surface by water-ammonia asteroids, these parameters can be changed within several decades. At the same time, the bombardment of Venus by asteroids will not only change the rotation parameters and, by establishing a change in seasons, allow the planet to cool greatly, but also cool the planet and its atmosphere due to the melting and evaporation of asteroid materials. Borrowing enormous energy from the atmosphere can occur due to the parallel passage of chemical reactions between carbon dioxide and sulfur dioxide gases of the atmosphere and ammonia.

The main methods of terraforming Venus:

• — bombardment by asteroids: water-ammonia ice;
• — biogenic impact: the introduction of terrestrial bacteria and algae that are stable in the upper layers of the atmosphere of Venus: (Pyrodictium occultum, Halobacterium salinarum, etc.).

— Mercury

Terraforming Mercury is an incomparably more difficult task than terraforming the Moon, Mars or Venus. The surface area of ​​Mercury is 75 million km², and the acceleration due to gravity is 3.7 m/s². It is capable of retaining a relatively dense atmosphere made from imported material (ammonia-water ice). A great difficulty in establishing a mild climate on Mercury is its close position to the Sun, its extremely slow rotation around its axis and the strong tilt of its axis of rotation. The level of solar energy falling on the surface of Mercury is very high and, depending on the time of year and latitude, ranges from 9.15 to 11 kW/m². With a precisely calculated bombardment of Mercury by asteroids, these shortcomings can be eliminated, but will require a very large expenditure of energy and time. It is likely that in the distant future humanity will have the ability to displace planets from their orbits. The most preferable would be to “raise” the orbit of Mercury by 20-30 million km from its current position. Solar energy can play an important role in the terraforming of Mercury, which can be effectively used even at the present stage of technology development. Mercury is a fairly dense planet and contains a large amount of metals (iron, nickel), and, possibly, a significant amount of nuclear fuel (uranium, thorium), which can be used for the development of the planet. In addition, Mercury's proximity to the Sun suggests the presence of significant reserves of helium-3 in surface rocks.

— Titan (satellite of Saturn)

Terraforming Saturn's moon Titan is a very distant prospect, and this is largely facilitated by its significant distance from the Sun. Titan is a fairly large body in the solar system and is larger in size than the planet Mercury (Titan's surface area is 83 million km²). The acceleration of gravity on Titan is 1.36 m/s². At the same time, Titan, due to appropriate natural conditions (no greenhouse effect, high albedo, that is, reflectivity), is largely cooled. It is estimated that in the absence of solar energy reflection, the average temperature of Titan's atmosphere would be 80 degrees higher, and temperature conditions would correspond to the current conditions on Mars, and in the presence of the greenhouse effect, they could be much more comfortable for people to live in special settlements on its surface. Titan is of interest to humanity for its significant natural hydrocarbon resources. Oceans, seas and lakes, composed primarily of liquid ethane, are valuable resources. Since the acceleration of gravity and, accordingly, the second cosmic velocity are small, the extraction of hydrocarbons will be much easier than on Earth, and, what is especially important, it is quite easy to pump hydrocarbon raw materials from the bowels of Titan. Increased extraction of raw materials and their removal from the planet will, along with reducing the volume of hydrocarbon smog in Titan's atmosphere, increase its transparency and heating by solar rays. Considering this process, it is worth noting that the consumption of hydrocarbon raw materials on Earth (oil, gas, coal) already exceeds 6-7 billion tons per year, and the need for it is growing, and pumping such a volume of hydrocarbons from the surface of Titan will significantly influence its climate. It is also possible that hydrocarbon raw materials will be needed in the future to supply not only the Earth, but also colonies on the Moon, Mars and Venus. Titan is also very interesting because it apparently contains huge amounts of liquid acetylene and mixtures of acetylene with ethane.

— Moons of Jupiter

- Europe. Europe has potential for terraforming. One of the advantages of Europe is the presence of water in liquid form. Its surface area is about 31 million km², slightly smaller than the surface area of ​​the Moon (37.9 million km²). The acceleration due to gravity on the surface of Europa is 1.32 m/s², and the level of solar energy perceived by Europa at present is about 18 W/m². One of the important advantages of Europe over many other planets is the presence of a gigantic amount of liquid water. However, there are also numerous difficulties with terraforming. For example, Europa is located in a huge and powerful radiation belt around Jupiter, and a person without protective equipment would die from radiation after 10-15 minutes of being on the surface of Europa. This circumstance requires the presence of radiation absorbers, the creation of which is impossible at the current level of technology development, or the movement of living beings under the surface of Europa's ocean. Also, a significant disadvantage of Europe for terraforming is low gravity, which is unable to maintain a sufficiently dense atmosphere for a long time (millions of years).

—Ganymede. The largest moon in the Solar System, larger than Mercury, Ganymede, due to a number of conditions, is a significant candidate for terraforming in the distant future. The surface area of ​​Ganymede is 87 million km² (17% of the Earth's area), and the acceleration due to gravity is 1.43 m/s² (slightly less than on the Moon). Currently, the amount of solar energy received by Ganymede is about 18 W/m², which is not enough to warm this planet. Enormous reserves of water ice and the possible presence of water in the liquid phase under its surface are real prerequisites for future terraforming. Ganymede, like Titan, is capable of retaining a powerful and dense atmosphere, and apparently has large reserves of gas hydrates deep below the surface, which could likely serve as a source of constant atmospheric replenishment. An important circumstance is the fact that Ganymede is located outside the radiation belts of Jupiter and has its own fairly powerful magnetic field, which suggests the presence of salty water deep under its icy crust.

- Callisto. Callisto, one of Jupiter's Galilean moons, is also a likely candidate for terraforming. Callisto's surface area is 73 million km² (14.3% of the Earth's area), the acceleration due to gravity is 1.25 m/s², and the light energy level averages about 18 W/m². Callisto has enormous reserves of water in the form of ice and is a geologically quiet planet. Like Ganymede, this satellite of Jupiter is located outside the powerful radiation belt, which is undoubtedly a great advantage over Europa and Io. Currently, Callisto is not well understood, and future research will show how likely it is to be successfully terraformed. Since Callisto's gravity is weak, it is unable to retain a dense atmosphere; however, the presence of an atmosphere is known, but it is extremely rarefied and consists of carbon dioxide. Callisto has a significant and sufficient amount of water and, apparently, gas hydrates to supply its own atmosphere for a long time. The presence of a weak magnetic field suggests the existence of a relatively vast ocean of salt water under a thick layer of surface ice. To create an atmosphere near Callisto, a powerful energy push is needed - heating the bowels of Callisto, drilling and a likely decrease in the surface albedo. Currently, the construction of domed settlements on the surface of Callisto seems more likely than full-fledged terraforming.

- And about. Considering the too high level of radiation and volcanic activity, it is least suitable for terraforming.

Other candidates for colonization.

Many planets and satellites of planets are considered theoretically (for example, Robert Zubrin “Settling the Outer Solar System: The Sources of Power”). Of the most frequently mentioned candidates, it is worth mentioning the remaining, smaller satellites of Saturn - Tethys, Dione, Rhea, Iapetus and Enceladus, where there may be liquid water, the largest asteroid Ceres, the five largest satellites of Uranus (Ariel, Oberon, Titania, Umbriel and Miranda) and Neptune's satellite - Triton, and even more distant dwarf planets and other objects - Pluto and Charon, etc. To populate these objects would require enormous amounts of energy.

At the present stage of technology development, the possibilities for terraforming climatic conditions on other planets are very limited. By the end of the 20th century, earthlings had the ability to launch rockets to the most distant planets of the solar system to carry out scientific tasks. The power and speed, as well as the possibility of large-scale launching of rockets into space at the beginning of the 21st century, have increased significantly, and if sponsored by major space powers such as Russia or the United States, today humanity is quite capable of performing certain tasks of terraforming planets. Currently, the capabilities of modern astronomy, rocketry, computer technology and other areas of high technology directly or indirectly make it possible, for example, to tow small asteroids, introduce small volumes of bacteria into the atmospheres or soil of other planets, and deliver the necessary energy, scientific and other equipment.

There has now been some level of cooperation between the various space agencies that in the past worked in parallel. Assuming that such practices continue to exist in the future, the development of space exploration technology will undoubtedly continue at a rapid pace. World GDP at the end of the first decade of the 21st century is about $70 trillion and, if there is agreement among world leaders, could allow for much more generous allocation of funds for space development. Considering that statistics on the development of the world economy indicate an acceleration in the pace of its development, we can assume that allocating a relatively small percentage of world GDP for financing could theoretically speed up the development of the necessary technologies tens of times and even hundreds of times (NASA’s budget, for example, in 2009 was about 17 billion dollars per year. From 1958 to 2008, NASA spent about $810.5 billion on space programs (taking into account inflation)

The most important tasks of earthly civilization to ensure the possibility of terraforming planets and their satellites are:

• — the interest of space powers is a necessary component to begin practical preparation and study of planets for terraforming;
• — the creation of economic funds and companies for the development of planets is a necessary public and private initiative for financial support of scientific projects;
• — development of observational astronomy - for the purpose of economical and rapid study of objects of the Solar system;
• — study of planets using probes - a source of detailed information about the planets and their composition;
• — development of the Earth's energy sector - provision of space launches and development of related areas of industry;
• — construction of sufficiently powerful rocket engines - work in the field of nuclear rocket engines, electronuclear propulsion systems, solar sails, ion rocket engines;
• — development of materials science - search for new materials and composites suitable for use for terraforming and construction of space vehicles;
• — development of biotechnology - the study of terrestrial microorganisms and putative microorganisms, breeding genetically modified microorganisms that are resistant to the natural conditions of terraformed planets.

The most important tasks of terraformist scientists:

— Reducing the cost of delivering cargo into space.

Terraforming planets implies the need to deliver a significant amount of cargo from the surface of the Earth to a high orbit; Due to the unacceptability of using nuclear rocket engines in the Earth's atmosphere and practical restrictions on the use of existing rocket engines, it is necessary to use alternative systems for delivering cargo into orbit: a space elevator, a space bridge (essentially a colossal spaceship; the cost of such a device can be measured in trillions of dollars), electromagnetic accelerator or “railgun” - such an accelerator is feasible in principle, but extremely expensive (hundreds of billions of dollars), the consent of the population and government agencies of any equatorial country is also necessary, since the route of this device will take thousands of km), an anti-gravity ship (at the moment impossible project), other projects (for example, a ground-based laser gun to accelerate a ship in space).

— Increasing the speed of interplanetary transportation.

Cargo delivered to high orbit will need to be delivered directly to the terraformable planet. Currently, the gravity of “passing” planets is used for interplanetary flights. This approach is not acceptable for regular cargo and passenger transportation within the Solar System. The use of nuclear rocket engines is necessary. Unlike a conventional chemical rocket, a nuclear engine can be a combination of a nuclear reactor and an ion engine, which economically consumes the working fluid and allows for a long period of active acceleration of the spacecraft. The principle of operation of an ion engine is the ionization of gas and its acceleration by an electrostatic field. Due to the high charge-to-mass ratio, it becomes possible to accelerate ions to very high speeds (210 km/s compared to 3-4.5 km/s for chemical rocket engines). Thus, a very high specific impulse can be achieved in an ion engine, which makes it possible to significantly reduce the consumption of reactive mass of ionized gas compared to the consumption of reactive mass in chemical rockets. The primary task is a significant (thousands of times) increase in the power of such engines and the creation of nuclear reactors corresponding to their power. Provided there is no atmosphere, the cargo ship can gradually accelerate, picking up speed from 10 to 100 km/s. Increasing flight speed is especially important for passenger transportation, in which it is necessary to reduce the radiation dose received by passengers, mainly by reducing flight time. The main difficulties in implementing work on nuclear rocket engines lie in both the high degree of radioactive contamination by engine emissions and the rejection of such technology by the population, as well as the environmental movement of the developing countries (leading countries are Russia, the USA).

— Organization of an industrial base on the Moon.

The moon has a variety of minerals, including metals valuable for industry - iron, aluminum, titanium; In the surface layer of the lunar soil, regolith, the isotope helium-3, rare on Earth, has accumulated, which can be used as fuel for thermonuclear reactors, where burning one kilogram of this isotope releases a colossal amount of energy - 19 megawatt-hours. To provide energy to the entire population of the Earth throughout the year, according to calculations by scientists from the Russian Institute of Geochemistry and Analytical Chemistry. Vernadsky, approximately 30 tons of helium-3 are needed. The purpose of the lunar base will be the creation and launch of spacecraft, interplanetary stations and manned spacecraft, while there will be no problems with delivering large weight and size ship components into the planet’s orbit due to the absence of an atmosphere and the low second escape velocity - 2.4 km/s instead of 11.2 km/ s on Earth (that is, the energy required to launch cargo into orbit of the Moon is 22 times less on the Moon than on Earth). However, it does not make sense to transfer all the necessary technology base for the production of spaceships to the Moon. It is more profitable to import a significant number of components from Earth for final assembly on the surface or orbit of the Moon. The result of colonization of the Moon should be the creation of permanent dome-type settlements.

— Thermonuclear energy and helium-3.

Helium-3 reserves on Earth range from 500 kg to 1 ton, but on the Moon it is found in significant quantities. Currently, a controlled thermonuclear reaction is carried out by the synthesis of deuterium 2H and tritium 3H with the release of helium-4 4He and the “fast” neutron n:

However, in this case, most of the released kinetic energy comes from the neutron. As a result of collisions of fragments with other atoms, this energy is converted into thermal energy. In addition, fast neutrons create a significant amount of radioactive waste. In contrast, the synthesis of deuterium and helium-3 3He does not produce radioactive products:

Where p is proton

This allows the use of simpler and more efficient systems for converting the kinetic synthesis reaction, such as a magnetohydrodynamic generator.

— Creation of self-replicating machines.

One of the significant obstacles to terraforming planets is the labor intensity of such projects. To get around this problem, it is proposed to use biological “machines”, namely genetically modified microorganisms, insects, etc. This does not solve all problems, since microorganisms and insects are not intelligent. In addition to reducing the labor intensity of the project, it is also necessary to take into account the conditions in which the terraformers will work. Life in space and on the surface of distant planets can be harmful to their health and psychologically unbearable. The use of robots can greatly reduce these difficulties, but it means that huge amounts of equipment would need to be transported from Earth, along with repair services and a significant stock of spare parts, which is also impractical. There is a third option, in which the builders do not build the object itself, but set up the production of construction equipment after arriving on the planet. For example, the colossal “atmospheric machines” featured in the movie Total Recall could take 20 years for 10,000 people operating typical construction equipment to build. If builders are replaced by robots, then approximately a thousand highly qualified people will be needed to repair and maintain the robots. By the same logic, if robots repair robots, it will be necessary to have about 100 people to control this process, and if instead of repairing construction robots, repair robots make new robots from materials collected on the inhabited planet, then in 2 years millions Thus obtained robot builders will put atmospheric machines into operation.

The presence of minerals on a terraforming planet is not guaranteed, and even if minerals are discovered, it may take several years to organize their extraction. In addition, there is a possibility of danger of the automated industrial complex leaving the control of its creators. One way or another, the question of practicality depends on the manufacturability of production. The creation of self-replicating machines at the microscopic level (nanotechnology) is still being developed at a theoretical level, but it is fundamentally possible. For terraforming the Moon, the most applicable intermediate option is when terraformists produce spare parts for the necessary equipment from available minerals, using components brought with them. For example, car bodies are made from an aluminum alloy mined on the Moon (eg Silumin), and then equipped with electronics created on Earth.

An alternative to terraforming is a more complete and rational use of the territorial and energy capabilities of the Earth itself. The Earth's surface area is 510.1 million km², which is larger than any other terrestrial planet in the solar system. At the same time, the land surface area is 148.9 million km², which is slightly more than the entire surface area of ​​Mars, and the area of ​​the world's oceans is 361.1 million km². With the growth of the technological level, it will become possible for humanity to more rationally use both the modern land area and the development of the bottom space of the world ocean, including through the development of underground infrastructure (moving large enterprises, power plants, parking lots underground, as well as the development of underground transport and housing ) and proper preparation of the ocean floor. The water surface is suitable for habitation even today. Pontoon-type structures (such as airports) are already being built in some densely populated countries. With the creation of cost-effective technologies, floating cities may appear. One of the most famous projects within the framework of which such developments are being carried out is “Freedom Ship”.

Since terraforming at the moment is a largely speculative technology based on currently existing technological solutions, similar in spirit to the colonization of uninhabited territories of the earth, it can be assumed that in the distant future the problems of human habitation on other planets will be solved not only by changing the appearance of these planets, but also in other ways similar to those used in the past. For example, the colonization of many tropical countries failed due to the high mortality rate of the colonists due to tropical diseases, and from such colonies often only the descendants of the colonists who mixed with the local residents remained. In science fiction, the problems of intelligent beings living in conditions alien to them are often “solved” by changing the biology of the people themselves - turning them into aliens, androids or god-like creatures (as, for example, in the Stargate series or in the film Superman). Also often used are solutions such as the existence of people in a completely simulated reality (as in the film The Matrix) or a partially simulated reality (a holodeck in the Star Trek series or an island made of stabilized neutrinos as in the film Solaris). In addition, such techniques as the use of teleportation technologies, protective screens, antigravity, etc. are often used. allowing people to exist in a vacuum, deadly high gravity radiation, etc.

Already at the dawn of understanding the processes of terraforming, it became clear that the consequences for the entire development of civilization would be of a radically new nature and global scale. These consequences will affect all aspects of human life, from the physiology of living organisms to religion. The nature of these consequences will be both positive and negative. In fact, as a result of relocation to other planets, people will have to accept completely new natural conditions, and this will be directly reflected both in people’s bodies and in their consciousness. For example, the discovery of America and the settlement of its territories had a very great impact on the course of development of the entire civilization, but it cannot be compared with the transformation that the settlement and terraforming of other planets brings with it.

Already at the beginning of space exploration, people encountered the phenomena of weightlessness and microgravity, discovering their amazing physiological effect on the human body. A different taste for food, muscle atrophy and much more forced earthlings to look at space with different eyes, and as a result, space medicine was born. In the event of resettlement and subsequent residence on other planets, earthlings will inevitably face significant changes in the functioning of organisms and the psychology of future generations of pioneers. Venus, Mars, the moons of Jupiter and Titan have less gravity than Earth, so animals and plants will have to adapt to the new conditions. The evolutionary process can lead to gigantism, or to nanism (dwarfism) - in conditions of low and high gravity, respectively.

> Terraforming the Moon

Colonization of the Moon into a habitable habitat. Read methods for creating colonies on a satellite, real research and the use of meteorites and comets.

From the very beginning of space exploration, writers have touched on the topic of colonization of alien worlds. All this was based on the theme of transformation, that is, the use of earthly technologies to normalize temperature, ecology, atmosphere, etc. The closest celestial object to us in the solar system is the Moon, so futurists wondered whether it was possible terraforming the moon.

The Earth's satellite is the most attractive target because it is close, we have already managed to land people there, we have the most information about it and we will spend the least time on delivery. What will colonization of the Moon look like?

Terraforming the Moon

Lunar colonization in literature

This is one of the most popular themes in science fiction. There are many examples of the use of domes or the construction of dwellings below the surface, but there have also been cases where the satellite itself became a suitable habitat.

The earliest is the story “A Parisian's Day in the 21st Century,” written in 1910 by Octave Bellard. He described how an atmospheric layer was gradually formed on the Moon, plants were planted and colonies were created.

In 1936, Paradise Lost appeared from C. L. Moore. At the center is the story of a spaceship pilot living in an inhabited system. Several stories about a lunar colony came from Arthur C. Clarke in the 1950s-1970s. In 1955, he had "Earthlight", where our satellite was caught in a firefight between the Earth and the united Mars and Venus.

In 1968, another of his novels, “2001: A Space Odyssey,” appeared, where there was an inhabited Moon and a strange monolith. Later they will shoot a film of the same name. Robert A. Heinlein wrote about settlements where a family of stones lived on the satellite.

There were also many novels about lunatics - lunar people forced to live underground. In some stories they were peaceful and even sent food and aid to Earth, while in others they declared war on us.

Lunar exploration

Recently, the topic of building a base on a satellite has been increasingly raised. The main impetus was the series of Apollo missions. Now many support the idea of ​​returning to the Moon before 2020. But these thoughts arose much earlier than the 20th century.

Back in 1638, Bishop John Wilkins wrote a treatise where he prophesied a lunar settlement. Konstantin Tsiolkovsky was the first to talk about a space elevator, who also argued that a lunar colony would be an important step in the exploration of deep space.

During the Apollo program, they discussed the idea of ​​not only landing astronauts on the surface, but also building a permanent post. In 1954, Arthur C. Clarke proposed the use of inflatable models that could be coated with lunar dust to provide protection and insulation.

He proposed that the astronauts first build needle-like structures and inflatable radio towers that would later become a large, stable dome. He also said that it was possible to purify the air using an algae filter, and provide energy with a nuclear reactor.

Ideas of colonizing the Moon with military bases also appeared. This was Project Horizon (USA) in 1967.

In 1962, a project arose with a lunar fort that could be located under the surface of the Sea of ​​\u200b\u200bTranquility, and the energy was created by nuclear reactors. In 2006, the Japanese announced their intention to create a base on the satellite by 2030. France and Russia spoke about the same thing in 2007.

In 2014, NASA representatives seriously took up the issue and in 2015 prepared the concept of a lunar settlement, where the main work would be done by robots.

Potential methods for terraforming the Moon

Let's not forget that such missions face a number of problems. Let's start with the fact that the Moon has a very thin layer of atmosphere (exosphere) and very few volatile elements. In the bottom picture you can see what a modified and developed Moon with a permanent colony will look like.

The problems can be solved by learning how to capture passing comets, which contain water ice and volatile substances inside. The comets would disperse and gradually form an atmospheric layer. Even impacts will release water hidden in the regolith.

The impulse from the comets will cause the lunar rotation to accelerate, and it will leave the block with our planet. A moon with a 24-hour cycle would be more adaptable. You can also use water ice craters for colonies. There you can quickly create an atmosphere and grow plants.

Potential Benefitsterraforming the moon

First of all, the Moon is closest to the Earth, so the costs of colonization will be significantly lower.

Moreover, it is much easier to direct comets in its direction. And if thousands are needed for other objects, then hundreds will suffice here. Surface water can be created from water ice in the lunar soil, as well as polar caches. To do this, you need to add ammonia or methane ices, which can be obtained from the Kuiper belt.

In addition, the colony will be able to provide for itself using local resources. The composition of the moon is similar to our planet, so they can be used as protection against radiation. The top layer of soil contains a lot of helium-3, which is used in fusion reactors.

The Moon is seen as a kind of transit base for long-distance space missions. It will be possible to use lunar water to form hydrogen fuel and this will save billions of dollars. Moreover, with the exploration of the Moon it will be much easier to move to Mars and beyond.

The satellite has low gravity, making the rocket easier to launch. In addition, this is a kind of training and an attempt to inhabit someone else’s object. After all, Martian conditions are much more hostile. Let's not forget about the whole network of lava tubes, the scale of which allows the creation of a large city.

Potential challenges whenterraforming the moon

We still don't have the necessary tools to collect comets on a massive scale, especially since we'll have to spend a lot of money to create them. Imagine that we need somewhere to get at least a hundred spaceships with a powerful engine capable of flying in both directions in a short period of time.

We are still trying to cope with the effects of microgravity, which atrophies muscles and destroys bones. The transformation of the satellite itself (creation of the atmosphere, ecology, vegetation) will take a lot of time.

Let's also not forget about the satellite's features. Lunar nights last 354 hours, so we need to somehow get by without solar energy (this does not apply to the polar regions). Settlements will need to create a heating source to cope with severe temperature fluctuations.

The lack of atmosphere leads to vulnerability to rays and meteorite impacts. Many problems are solved by underground colonies near the polar regions, which are the most illuminated. Or you will have to use thermonuclear reactors.

Why is it so painful? Because among all the objects in the solar system, the Moon is the cheapest option. This is an attempt to conquer a celestial body and test our strength. In addition, its resources can be used on Earth.