One day in the distant future it will be our last quiet day on Earth. Someday, over billions of years, the sky is on fire. The sun will swell fiery ball raging hell will fill the heavens. The temperature on Earth will jump sharply, the oceans will boil and evaporate, leaving charred parched desert. The mountains gradually melts and flows of lava flows on the site where once stood the full life of the city.

The laws of nature tell us that this gloomy scenario is our inevitable future. One day Earth will perish in the flames and will be swallowed up by the Sun. It is a law of nature.

The catastrophe will occur within the next 5 billion years. In this space the scale of the rise and fall of human civilizations seems tiny ripples on the surface of the ocean of time. Someday we'll have to leave Earth or die. And when the conditions on Earth will become unbearable, humanity, our descendants will have to do something. What?

Mathematician and philosopher Bertrand Russell once said, "that no fire, no heroism, no power of thoughts or feelings cannot save a life after the grave; that all the labors of the ages, all the devotion, all the inspiration, all the noonday brightness of human genius, are destined to death in a giant fire in the Solar system; and the whole temple achievements Person inevitably be buried beneath the ruins of the Universe...".

For me his words - one of the most otraslei statements. But Russell wrote in the times when the rocket ships was considered impossible. Today, the prospect of ever leave the Earth does not seem so fantastic. Carl Sagan once said that we ought to be "deplanatum views". Life on Earth is so precious, he said that it should be extended for at least another one planet - disaster. The earth moves in the space dash", full of asteroids, comets and other debris floating near its orbit. A collision with any of them can lead to the destruction of humanity.
Impending disaster

The poet Robert frost wondered how the Earth will perish in the flames or ice? We, knowing the laws of nature, we can confidently assume, what will be the end of the world in case of natural disaster.

If to speak about thousands of years, one of the threats to our civilization, is the coming of a new ice age. The last such period ended 10 000 years ago. Another 10-20 thousand years, when will come the next, most of North America may be at kilometre of ice. The flowering of human civilization falls on the current short interglacial period, when the Earth's climate is unusually warm, but this situation cannot last forever.

If we talk about millions of years, then a catastrophic effect can bring collision with the Earth of any large meteorite or comet. The last such collision occurred 65 million years ago, when on the Yucatan Peninsula in Mexico collapsed object about Upsovernight. On the site of the crash occurred crater with a diameter of about 300 km the Result of it was the extinction of the dinosaurs dominated the Earth life forms. In this time scale is another cosmic collision seems possible.

In a few billion years, the Sun, gradually expanding, will devour the Earth. Moreover, according to our estimates, for the nearest billion years the Sun will be warmed up by about 10% and will burn the Earth. In 5 billion years the Sun will become a red giant and in the process of this evolution will fully absorb our planet. The earth is inside of the star's atmosphere.

Over 10 billion years old will die and the Sun and the milky Way galaxy. Our Sun, finally exhausted the reserves of the hydrogen-helium fuel, compressed and turned into a tiny white dwarf; gradually star cools, and over time from her in the void will only black com nuclear slag. The milky Way galaxy will collide with the neighbor, a much larger galaxy - the Andromeda Galaxy. Spiral arm of the milky Way will be cut off, and our Sun, quite possibly, will be thrown into the void of space. Black holes in the centers of the two galaxies, Spasov dance of death, in the end will collide and merge.

So, it is established that humanity has ever leave the Solar system and move to a neighboring stars or perish. The question remains: how to get there? To the nearest to us star, alpha Centauri, more than 4 light years. Conventional missiles with chemical jet engines, workhorses of the current space program, difficult to develop speed up to 18 km/S. With this speed to fly to the nearest star would have 70 000 years.

Analyzing the space program, it should be noted that our current capabilities and characteristics of this spaceship that would allow us to begin the study of the Universe, there is a huge gap. After in the beginning of the 1970s ended the study of the moon, our manned program included work astronauts on the orbits of no higher than 500-600 km on shuttles and the International space station. However, in 2010, NASA plans to stop flying the Shuttle and create instead a spaceship "Orion"; the same ship will by 2020 again - after half a century - to deliver astronauts to the moon. It is planned to organize on the moon permanent manned base. After that, possibly, will be sent a manned expedition to Mars.

Obviously, if we are ever to get to the stars, we need missiles completely different type. It is necessary to radically increase or cravings of our engines, or the time of their work. For example, large with a chemical rocket engines may have a thrust of several thousand tons, but it will be only a few minutes. Conversely, the rocket engine of another type, for example ion (it will be described below), although it has a small thrust, but to work in the open space capable years. Where it comes to missiles, the turtle is always going to beat the hare.
Ion and plasma engines

Unlike chemical jet engines, ion do not produce sudden and very effective emission from hot gas, which, in fact, pushing traditional rockets. Their desire is usually measured in tons, and in grams. If this engine on Earth to put on the table, he didn't have the strength to move. But all these engines nedobraya in traction, they more than compensate for the duration of the work; in the vacuum of outer space, they are able to work for years[25].

Typical ion engine resembles the inside of a television tube - tube. Electric current warms up the thread, which, in turn, produces a stream of ionized atoms, for example, xenon, which is then dumped through the nozzle. Instead of a jet of hot, explosive gas ion engine throws slight but steady flow of ions.

In 1998, NASA conducted a successful launch of the probe Deep space 1 ion engine NSTAR on Board; the engine ran for a total of 678 days, setting a new record. The European space Agency has also tested the ion engine on Board the moon apparatus SMART-1. Japanese space probe "Hayabusa", which approached the asteroid, has made landing at him and soil collection, worked four xenon ion engine. In General, ion engine characteristics looks not brilliantly, but capable of serving distant (and not too hasty) expeditions to other planets. Maybe someday ion engine will be unassuming workhorse interplanetary transport.

Plasma engine is a more powerful version of the ion. As an example of this engine can be called VASIMR (variable specific impulse magnetoplasma rocket - magnetoplasma rocket with a variable specific impulse); to disperse in space it uses a powerful stream of plasma. This engine was developed by astronaut and engineer Franklin Chang-Diaz. Hydrogen it is heated to a temperature of several million degrees by means of radio waves and magnetic fields. Very hot plasma ejected then through the nozzle missiles, while pursuing a significant traction. On Earth prototype engines already created and tested, but in space none of them have not yet flown. Some engineers hope that plasma engine can be used when creating a vehicle for mission to Mars; this would significantly, up to several months, reduce travel time. Some developments offer to use to heat the plasma in the engine solar energy. Others suggest to use the energy of nuclear disintegration (this, of course, there are additional security problems - after all, have to send into space large number of nuclear materials, and the spacecraft is exposed to all sorts of accidents).

But neither ion, neither the plasma engine will have no power to deliver us to the stars. This will require a jet engines, based on entirely different principles. One of the serious problems in the development of the ship - is a monstrous amount of fuel needed to travel even to the nearest star, and a long period of time that will be required for this journey.
Solar sail

Solar sail is an idea that could solve many problemsvolumes. It is based on the fact that sunlight has a very small but constant pressure, sufficient to carry through space huge sail. The idea of a solar sail is not new, it belongs to the great astronomer Johann Kepler, and set out for the first time in his treatise "the Dream" 1611

The idea is based on quite simple laws, but the development of the real solar sail, which could be launched into space, was slow and like jerks. In 2004 Japanese rocket successfully delivered into space two small experimental solar sails. In 2005, the Planetary society, the company "Cosmos studios and the Russian Academy of Sciences launched from a submarine in the Barents sea space sail "Cosmos-1"; unfortunately, rocket "Wave", which he was, failed and the device is not went into orbit. (A previous attempt to launch suborbital sail in 2001, also failed.) In February 2006, the Japanese rocket M-V has successfully put into orbit a five-metre sail, but revealed he is not fully[26].

Research and experiments in the field of creation of solar sails are moving really slowly, but his supporters are already proposed a new idea, which could bring a person closer to the stars. It is proposed to build on the moon huge battery of lasers that would be allowed by the powerful rays in the solar sail; it would allow him to reach the nearest star. Parameters interstellar solar sails are simply afraid. The sail should be hundreds of kilometers across, and make it necessary and completely in the open space. On the moon would have to build thousands of high-power lasers that can work for years or even decades. (According to one estimate, each of these lasers have a thousand times superior to radiation power of all of today's planet Earth.)

Theoretically giant solar sail can reach speeds of up to half the speed of light. The ship with such a sail on the way to the nearest stars would only need about eight years. Mover on this principle is good for the fact that all the principles are already known. Milking its creation is not required to open a new physical laws. But in full growth up other problems - both economic and technical. The construction of the sails of a diameter of a few hundred kilometres, and construction on the moon thousands of high-power lasers are very serious engineering problem - and necessary for the project realization technologies will be yet not soon. (The main problem interstellar solar sails - back. To bring the ship back to Earth, will have to build on the moon among the stars-goal second battery lasers. Or do about this star rapid gravitational maneuver that will help to pick up speed for the return journey. Then the laser on the moon can be used for braking the sail that ship could sit down.)
Once-through nuclear engine

To me personally the most promising vehicles to travel to the stars seems once-through nuclear fusion engine. The Universe has more than enough hydrogen, so ship with this engine could collect hydrogen - i.e. fuel - by the way, in the process of movement in the open space. Essentially, the engines would be inexhaustible and always available source of fuel. The collected hydrogen is then heated up to several million degrees is enough for fusion and saving energy.

The principle of once-through nuclear engine offered in 1960 physicist Robert Bussard; after his promotion was doing and Carl Sagan. Bussard calculated that once-through nuclear fusion engine weighing about 1,000 tons could theoretically maintain a constant acceleration of 1 g, i.e. comparable to the effect of earth's gravity. Imagine that this acceleration is supported during the year. During this time the ship is up to 77% of the speed of light; this is already enough to seriously consider the possibility of interstellar travel.

Characteristics of a once-through nuclear engine it is easy to calculate. First, we know the average density of gaseous hydrogen in the universe. In addition, we can calculate how much hydrogen it is necessary to burn in order to reach the speed up to 1G. This calculation, in turn, determines how large should be "funnel" for collection of hydrogen. With some assumptions can be shown that we would need crater with a diameter of about 160 miles. While you can create a funnel of this size would be prohibitively difficult on Earth, in space it would be easier thanks to weightlessness.

In principle, the direct-flow engine can go on an indefinite distance, eventually reaching distant star systems in the galaxy. As Einstein inside the rocket time slows down, could be overcome astronomical distances without suspended animation. After reaching the acceleration of 1G, for eleven years (in accordance with the clock inside the spaceship) spacecraft will reach the Pleiades star cluster, which is 400 light years from Earth. Twenty-three years he reaches of the galaxy of Andromeda, which is 2 million light-years from Earth. In theory, the spacecraft will be able to reach the limits of the visible universe during the life of the crew members (although on the Earth during this time, probably billions of years).

One of the key problems is actually a fusion reaction. The synthesis reactor ITER, which is planned to construct in the South of France, combines two rare isotope of hydrogen (deuterium and tritium) with the purpose of obtaining energy. In space, however, the most common form of hydrogen (protium) consists of one proton surrounded by electrons. Therefore, pryamotochno engine synthesis should use the proton-proton reaction of synthesis. Although the process of synthesis with participation of deuterium/tritium has been studied for decades, the proton-proton fusion is much less studied. It is much more difficult to achieve, and it gives much less energy. So the development of proton-proton reactions will remain a technical challenge in the coming decades. (In addition, some experts Express doubts whether the direct-flow engine to overcome the effects of the resistance of the environment as it approaches the speed of light)

While Fizicheskie and economic aspects of proton-proton fusion is not developed, it is difficult to give a precise assessment of the capabilities of the direct-flow engines. But this type of engine is among the promising candidates on a mission flight to the stars.
Nuclear electric rocket dvigatel

In 1956, the Commission on atomic energy of the USA (AEC) began to seriously consider nuclear missiles in the framework of the project Rover. In theory, nuclear reactor should be used for warming gases (e.g. hydrogen) to extremely high temperatures. Then these gases will be released from the rocket nozzle, creating thrust.

Because of the risk of explosion and falling into the Earth's atmosphere toxic nuclear fuel, early versions of nuclear rocket engines were placed horizontally on the railroad tracks, where carefully examine their performance. The first nuclear missile engine, designed to test the project Rover in 1959, was Kiwi 1 (aptly named after the Australian flightless birds). In the 1960's NASA together with AEC has created a nuclear engine for rocket vehicle (Nuclear Engine for Rocket Vehicle Applications, NERVA, which is the first nuclear rocket that was experienced in the vertical, not horizontal. In 1968 it was launched at the stand of the nozzle up.

The results of these studies has been very controversial. The rocket was extremely complex, and trials often ended in failure. In a nuclear engine appeared very strong vibration, shell fuel assemblies burst, and the missile was falling apart. Another ongoing issue was corrosion because of the burning of hydrogen at high temperature. Finally in 1972 nuclear rocket program was closed.

(These nuclear missiles was another problem: the danger of the beginning of spontaneous nuclear reaction that would be equivalent to the explosion of a small nuclear bomb. In nuclear power plants today, the nuclear fuel is present in low concentrations, and they can't explode like the Hiroshima bomb. But the nuclear rocket engines for maximum traction worked with highly enriched uranium, and therefore could in principle be a chain reaction and, accordingly, an atomic explosion. Before the closing scientists decided to have one more, final test - try to blow up the rocket as the atomic bomb. They were removed from the reactor control rods that help keep the reaction under control. The reactor obediently moved in supercritical state and exploded fierce fire ball. This impressive end of the program on development of nuclear rocket engines even captured on film. The Russians were unhappy. They found the trick violation of the Agreement on partial nuclear test ban, according to which all the explosions of atomic bombs, with the exception of the underground, was banned.)

From time to time, the military returned to the idea of nuclear missiles. One of the secret projects of this kind was called "Timberwind" and was in the 1980s, part of the military program "star wars". (It was abandoned after the Federation of American scientists published information about its existence.)

The main problem of nuclear rocket engines - safety. Even now, fifty years after the beginning of the space age, launching missiles into chemical fuels sometimes (about 1% of cases) end disastrously. (The destruction of the space Shuttle "Challenger and Columbia, which have found their death 14 astronauts, also confirms the statistics of accidents.)<br />
However, a few years ago, NASA resumed research on nuclear rocket for the first time after the program NERVA 1960-H. In 2003, NASA has dubbed its new project "Prometheus" in honour of the Greek God gave humankind the fire. In 2005, the program "Prometheus" was allocated 430 million, but in 2006, the funding has been reduced to 100 million. Currently the future of this project is unclear[27].
Pulsed nuclear engine

Another theoretical possibility is to use as the mover of a series of nuclear mini-bomb. For example, the Orion project envisaged serial throwing small thermonuclear bombs behind the ship, so that he could "ride" shock wave from the explosion. Theoretically, such a system capable of propelling a spacecraft up to speeds close to the speed of light. The idea of such a vehicle, first expressed in 1947, Stanislaw Ulam, who participated in the development of the first hydrogen bombs; later it was developed Ted Taylor, one of the main designers of nuclear warheads for the American military, and physicist Freeman Dyson of the Institute for advanced study in Princeton.

In the late 1950s and 1960s were conducted thorough calculations for the starship based on this principle. According to estimates, it could have a year to go to Pluto and back, reaching the rate of 10% the speed of light[28]. But even at that speed up to the nearest star would have to fly 44 years. Scientists considered the options when the cosmic ark with such a mover was flying would be in space for several centuries; in the crew change of generation, and many had to live life in a moving world, to their descendants could get to nearby stars.

In 1959 the company General Atomics has released a report, which assessed the size of the ship type "Orion". The largest version, called the report "super Orion", had to weigh 8 million tonnes, to have a diameter of 400 m and move on shock wave from more than thousands of hydrogen bombs.

The main problem associated with this project, the possibility of contamination of the launch area of nuclear precipitation. Assessment Dyson, nuclear fallout from each run can cause fatal form of cancer in ten people. Also, the electromagnetic pulse from the explosion was so great that certainly would have caused a lot of short circuits in the nearby electrical systems.

Signing in 1963 Treaty on the partial test ban Treaty was the death knell for this project. Eventually surrendered even its main supporter, the developer of nuclear bombs Ted Taylor. (He once told me that finally disappointed in the project when they realized that the technical know-how such a project can use the terrorists to create a portable nuclear bombs.

The project was closed as too dangerous, but his name lives on in the name of the spacecraft "Orion", which NASA plans in 2015 to replace the space shuttles.)

In 1973-1978 the concept of the spaceship with nuclear propulsion was briefly revived in the project "Dedal" the British interplanetary society. The project was a preliminary study possibilities of construction of unmanned vehicle capable of reaching the stars Barnard - it is separated from the Earth, the distance 5.9 light year. (Star Barnard was chosen as a target because it was supposed presence near her planet. Since then, astronomers Jill Tarter and Margaret Turnbull made a list of 17129 not too distant stars, near which may be suitable for life of the planet. The most promising candidate - Epsilon Indians And is away from us 11,8 light year.)

The rocket ship on the project "Dedal" was so huge that the building he had been in the open space. She had to weigh 54 000 tons (almost all weight - rocket fuel) and could accelerate to 7.1% the speed of light, carrying payloads weighing 450 tons In contrast to the Orion project, designed for use tiny atomic bombs, the project "Dedal" involved the use of miniature hydrogen bombs with a mixture of deuterium and helium-3 and ignition system using electronic beams. But the enormous technical challenges and concerns related to nuclear propulsion, led to the fact that the project "Dedal" was postponed indefinitely.
Specific impulse and efficiency of the engine

If you want to compare the effectiveness of different types of engines, engineers usually talk about specific impulse. Specific impulse is defined as the change in the momentum per unit mass of fuel consumed. Thus, the more efficient engine, the less fuel is required for the conclusion of a rocket into space. The impetus, in its turn, is the result of the force for a certain period of time. Chemical rockets, though, and have a very high thrust, work for a few minutes, and therefore have very low specific impulse. Ion engines, able to work for years, can have high specific impulse at a very low powered.

Specific impulse is measured in seconds. The average with a chemical rocket engine, may have specific impulse to 400-500 C. So, the engine's specific impulse of the Shuttle is 453 S. (highest obtained so far as specific impulse for chemical rocket engine amounted to 542; as fuel this engine used exotic mixture of hydrogen, lithium fluoride.) Ion engine apparatus SMART-1 had specific impulse 1640 S. nuclear rocket engines this parameter reaches 850 C.

The maximum possible specific impulse would have a missile that can reach the speed of light. Its specific impulse would be around 30 million Below is the table of specific impulses, characteristic for various types of jet engines.

Engine type (Specific impulse)

Solid fuel (250)

Liquid (450)

Ion (3000)

Plasma VASIMR (1000 - 30000)

Atomic (800 - 1000)

Thermonuclear direct-flow (2500 - 200000)

Nuclear pulse (10000 - 1000000)

On antimatter (1000000 - 10000000)

(In principle, laser sail and direct-flow engine do not carry spare fuel, and therefore the specific impulse is not an essential feature; however, these structures have their own problems.)
Space Elevator

One of the major impediments to the implementation of many of the star project is that because of the huge size and weight of the ship cannot be built on Earth. Some scientists propose to collect them in the open space, where, because of weightlessness astronauts will be able to easily raise and roll incredibly heavy objects. But today, critics rightly point out beyond the cost of the space Assembly. For example, to complete Assembly of the International space station will take about 50 Shuttle launches, and its cost of these flights is approaching $ 100 billion. This is the most expensive scientific project in the history, but the construction of the outer space interstellar space sailing ship or ship with direct-flow funnel would cost many times more expensive.

But, as was fond of saying fiction writer Robert Heinlein, if you can rise above the Earth, at 160 km, you are already halfway to any point in the Solar system. This is because any time you open the first 160 km, when the rocket to disentangle themselves from the shackles of gravity, "eat" the lion's share of the cost. After this the ship, we can say that already able to get though to Pluto, though further.

One of the ways to drastically reduce the future cost of flight - to build a space Elevator. The idea is to get to heaven on the rope is not new - to take the story of Jack and the bean seed"; tale tale, but if you bring the end of the rope into space, the idea could become a reality. In this case the centrifugal force of the Earth's rotation would be enough to neutralize the force of gravity, and the rope would never have fell to the ground. She magically rising straight up and disappeared in the clouds.

(Imagine the ball, which you turn on a string. It seems that the ball is not on the force of gravity; the fact that the centrifugal force pushes it away from the center of rotation. Similarly, a very long rope can hang in the air due to the rotation of the Earth.) To keep the rope is not required, the Earth's rotation will be enough. In theory people could climb on a rope and climb right into space. Sometimes we ask students-physicists to calculate the tension of such ropes. It is easy to show that this tension will not withstand even the steel cable; that is why for a long time it was believed that the space Elevator is not possible.

The first scientist who is seriously interested in the problem space Elevator, became Russian scientist-the seer Konstantin Tsiolkovsky. In 1895 under the impression from the Eiffel tower he imagined the tower, which would go right up into space and connected the Earth floating in space "star castle". Build it was assumed from the bottom up, starting from the Ground, where engineers would have to slowly build up to the heavens space Elevator.

In 1957, a Russian scientist Yuri Artsutanov suggested a new solution: build a space Elevator reverse order, from top to bottom, starting from space. The author imagined a satellite in a geostationary orbit at a distance of 36 000 km from the Earth is from the Earth, he will appear to be fixed; that satellite was proposed to omit to Earth the cable, and then attach it to the bottom point. The problem is that the cable for the space Elevator would have to withstand the tension around 60-100 HPa. Steel torn when tension about 2 HPa that deprives the idea of its meaning.

Wider audience got acquainted with the idea of a space Elevator later, in 1979, his novel Andrture Clark "the Fountains of Paradise", and in 1982 novel by Robert Heinlein's Friday. But because progress in this direction has stalled, forgot about it.

The situation changed dramatically, when chemists invented carbon nanotubes. The interest in them has increased dramatically after the publication in 1991 work Sumio Iijima of Nippon Electric company. (I must say that the existence of carbon nano-tubes has been known since the 1950s, but for a long time they did not pay attention.) Nanotubes much stronger, but it is much easier steel cables. Strictly speaking, strength, they even exceed the level required for a space Elevator. According to scientists, the fibers of carbon nanotubes must withstand a pressure of 120 GPA, well above the required minimum. After this discovery attempts to create a space Elevator recommenced.

B 1999 was published serious study by NASA; it was considered a space Elevator in the form of a tape of a width of approximately one meter in length and about 47 000 km, capable of delivering into orbit around the Earth payload weight of about 15 tons, a similar project was instantly and completely changed the economic side of space travel. The cost of delivery of cargo to orbit once would have decreased in 10 000 times; such changes as otherwise not be called revolutionary.

Currently, the delivery of one pound of cargo into earth orbit is not less than $ 10,000. So, every flight of the Shuttle costs about $ 700 million. Space Elevator has brought down the cost of delivery to 1 USD. per pound. Such a radical reduction of the space program could completely change our views on space travel. A simple click you could run the Elevator and go up into open space for a sum corresponding to the value of, say, a plane ticket.

But before building a space Elevator that you can easily get to heaven, we have to overcome serious obstacles. Currently the longest fibers of carbon nanotubes obtained in the laboratory, the length does not exceed 15 mm For a space Elevator would require cables, of nanotubes in thousands of kilometers. Of course, from a scientific point of view this is a purely technical problem, but needs to be addressed, and it can be stubborn and difficult. However, many scientists are convinced that the mastery of the technology of production of long ropes of carbon nanotubes we have several decades.

The second problem is that due to the microscopic violations structure of carbon nanotubes getting long cables, it may never be problematic. Assessment Nicola Pugno from the Turin Polytechnic Institute, if at least one atom at carbon nanotube is not in its place, the strength of the tube can be decreased by 30%. In General defects at the atomic level can strip the cable from nanotubes 70% strength; it is permissible load is below the minimum GPA, without which it is impossible to build a space Elevator.

In an effort to spur the interest of private entrepreneurs to the development of a space Elevator, NASA announced two separate competition. (A sample was taken contest Ansari X-Prize for a prize of 10 million. The competition successfully aroused interest enterprising investors to create commercial rockets, capable to lift passengers to the border of outer space; declared the prize was awarded in 2004, the spacecraft SpaceShipOne.} Contests NASA are named Beam Power Challenge and Tether Challenge.

To win the first of them, the research team should create a mechanical device that is able to lift a weight of not less than 25 kg (including own weight) up on the rope hanging, say, on the boom of the crane) with a speed of 1 m/s at a height of 50 m is Possible, the task seems simple, but the problem is that this product must not use fuel, batteries or power cable. Instead, the robot-Elevator must be powered by solar panels, solar lights, laser or microwave radiation, i.e. of those energy sources that are easy to use in space.

In order to win the competition Tether Challenge, the team must submit a two-meter pieces of rope weighing not more than two grams each; this cable should carry the load by 50% more than the best example of the previous year. The goal of this contest is to stimulate research on the development of ultra-light materials of sufficient strength and that they could reach 100 000 km in space. Winners will award in the size 150 000,40 000 and 10 000. (To emphasize the complexity of the task, in 2005 - the first year of the contest - prize was not awarded.)

Of course, working space Elevator can dramatically change the space program, but it has its disadvantages. So, the trajectory of motion of satellites in low earth orbit are constantly being shifted from the Earth because the Earth rotates underneath). This means that over time, any of the satellites may encounter a space Elevator at a speed of 8 km/s; this will be more than enough to break the rope. To prevent such catastrophes in the future will either be provided on each satellite is small rockets, which would have given him the opportunity to bypass the Elevator, or provide the rope small rockets, so he could get away with satellite paths.

In addition, the problem may be clashes with micrometeorites because the space Elevator will rise beyond the earth's atmosphere, which in most cases protects us from meteors. As to predict such collisions is not possible, the space Elevator would have to provide additional protection and perhaps even failover backup systems. The problem can present atmospheric phenomena such as hurricanes, tidal waves and storms.
Gravitational maneuver

There is another way to accelerate to speeds close to the speed of light, is to use the "slingshot effect". When sending space probes to other planets NASA sometimes causes them to maneuver around a neighboring planet, to take advantage of the "slingshot effect", in addition to disperse the device. So NASA saves valuable rocket fuel. In this way the unit Voyager-2" managed to reach Neptune's orbit, which is at the very edge of the Solar system.

Freeman Dyson, a physicist at Princeton, has put forward an interesting proposal. If someday in the distant future of humanity, to be found in space for two neutron stars revolving around a common center with high speed, the Terran ship, flying very close to one of these stars, maybe due to gravitational maneuver to gain speed, equal to almost one third of speed of light. As a result, the ship accelerated up to relativistic velocities due to gravity. Theoretically this could happen.

Other scientists suggest to use our own sun. This method was used, for example, the crew of the ship "enterprise" in the movie Star trek IV: the Voyage home." Ognev the Klingon ship, the crew of "enterprise" sent it in close to the Sun trajectory to break the light barrier and go back in time. In the film, "When worlds collide" the Earth is threatened by a collision with an asteroid. To escape from the doomed planet, scientists are building huge construction like a roller coaster. Going down from the hill, rocket ship is gaining a tremendous speed, then turn down to a small radius and forth in space.

Only actually none of these ways to accelerate with the help of gravitation does not work. (Law of conservation of energy says that truck on a roller coaster, dispersed on the descent and slowing down on the rise, it appears at the top of exactly the same speed as in the beginning - no increment of energy occurs. Similarly, turning around a stationary Sun, we will end up with exactly the same speed with which started maneuver.) Method Dyson two neutron stars in principle might work, but only because the neutron star move quickly. Spacecraft that uses gravitation maneuver is incremented energy due to the movement of a planet or star. If they are fixed, this maneuver will give nothing.

And the proposal Dyson, although it might work, nobody can help today's earth scientists - in order to come to a rapidly rotating neutron stars, need to start to build a spaceship.
From the gun in heaven

Another clever way to bring the ship into space and to accelerate to the fantastic speed, shoot them from electromagnetic rail guns", which is described in his works of Arthur C. Clarke and other authors-fiction writers. Currently this project seriously considered as a possible part of the missile shield program "star wars".

The method consists in the fact that instead of rocket fuel or gunpowder be used to accelerate the rocket to a high velocity energy electromagnetism.

In the simplest case rail gun represents two parallel wires or rail; missile or missile, "sits" on both rails, forming a U-shaped configuration. Even Michael Faraday knew that on the frame with an electric current in a magnetic field force. (Generally speaking, this principle is a all motors.) If you skip through tracks and the projectile electric current force in millions ampere, around the entire system will have an extremely powerful magnetic field, which, in turn, will direct the projectile on rails will drive him to the huge speed and will kick into the space at the end of the rail system.

During testing, electromagnetic rail guns successfully fired a metal objects with great speed, dispersing them at very short distances. Which is fine, in theory conventional rail gun is capable of firing a metal shell with a speed of 8 km/s; this is enough to bring it into orbit. In principle, the entire rocket fleet NASA could be replaced rail guns that right from the Earth's surface fires would payload into orbit.

Rail gun has significant advantages with respect to chemical guns and missiles. When you shoot a gun, the maximum speed at which the expanding gases can push the bullet out of the barrel, is limited by the speed of propagation of the shock wave. Jules Bern in the classic novel "From the Earth to the moon" shot shell with astronauts to the moon with gunpowder, but actually it is easy to calculate that the maximum speed that can give the shell powder charge, much less than the speed required for a flight to the moon. Rail same gun does not use the explosive expansion of gases and therefore does not depend on the velocity of propagation of the shock wave.

But rail guns their problems. Objects are accelerated so quickly that they, as a rule, splashimages from collisions... with air. Payload is greatly deformed in the process of "shots" of the barrels rail guns, because when the projectile into the air, it's like as if he'd hit a brick wall. Moreover, with the acceleration of the projectile is experiencing tremendous acceleration, which is in itself capable strongly distort the cargo. The rails must be regularly replaced, as the projectile in motion also distorts them. Moreover, overload in rail gun kill people; human bones will not stand such acceleration will collapse.

One solution is to install the rail gun on the moon. There, outside the earth's atmosphere, the projectile will be able to accelerate in the vacuum of outer space. But even on the moon, the projectile during acceleration will experience enormous overload that can damage and impair the payload. In a sense rail gun - antipode laser sail, which picks up speed gradually over time. Restrictions rail guns are defined precisely because it is at a short distance, and for a short time passes body enormous energy.

Rail gun, able to fire the machine to the nearest stars, would be a very expensive construction. So, one of the projects envisages construction in the open space rail guns length of two-thirds of the distance from the earth to the Sun. This gun will accumulate solar energy, and then time to spend it, dispersing desyatinoy payload up to speed equal to one third of speed of light. This missile will experience an overload in 5000 g. Of course, "survive" this will start only the most hardy ships-robots.
The danger of space travel

Of course, space travel is not a country picnic, In a manned flight to Mars or beyond human await a terrible danger. Millions of years of life on Earth evolved under reliable protection of the ozone layer protects the planet from harmful ultraviolet rays, magnetic field protects from solar flares and cosmic radiation, and the thick atmosphere of the covers from the meteors that have time to burn in its column. Moderate temperatures and fluctuations of atmospheric pressure seem natural. But in deep space we will have face-to-face to face with the fact that a large part of the Universe is in a state of chaos will be faced with deadly radiation belts and meteor swarms.

The first problem prolonged space travel, which must be solved, is a weightlessness. Conducted by the Russian-term studies of weightlessness showed that the human body in space loses vital minerals and chemicals much faster than expected. Does not save even a strict exercise program: after a year on orbital bone and muscle Russian cosmonauts so atrophy that after returning to Earth, they are able only to crawl like a baby, and then work[29]. It seems that the inevitable consequences of a prolonged stay in weightlessness during space flight are muscle atrophy, wear, musculoskeletal system, reducing the production of red blood cells, a decrease in immune response, the weakening of cardiovascular activity.

Flight to Mars, which can last from several months to a year, is at the limit of endurance of our astronauts. In the long flight to the nearest stars this problem can be fatal. Perhaps for the sake of the lives of the crew of the spaceship of the future will have to spin, creating at the expense of centrifugal forces artificial gravity. This requirement greatly complicate the design and will raise the cost of the spaceship.

The second problem is that due to the presence in space meteorites with velocities in the tens of kilometers per second, it might have to equip spaceships additional protection. A thorough examination of the case of the space Shuttle showed signs of falling short tiny, but is fraught with mortal danger of meteorites. It may well be that at the space vehicles of the future will have to arrange a special room for the crew and to provide double protection.

The radiation level in deep space, far higher than previously thought. So, during 11-year cycle of solar flares can send to Earth a huge number of deadly plasma. This phenomenon than once forced the astronauts on the space station to look for additional protection against potentially dangerous residue of subatomic particles, and a walk in open space at such a moment would be fatal. (Even during a transatlantic flight from Los Angeles to new York, for example, we are exposed radiation intensity of about 1 mrem/H. During a flight each passenger receives the same radiation dose, as in x-ray picture of the tooth.) In deep space where we don't protect the Earth's atmosphere, its magnetic field, radiation can become a serious problem.
The temporary cessation of vital functions

Whatever we say about the flight to the stars, whatever projects are not developed, one fact remains: even if we manage to build a spaceship to travel to the nearest stars we will be decades or even centuries. For such flight will take generations crew, and to the destination will get only the descendants of those who have gone to a way.

One solution to this problem, appearing in such films as "Strange" and "planet of the apes," to put space travellers anabiosis; this means carefully and slowly lower the body temperature to a level at which halted a shipment of all vital functions. Some animals make such an operation every year during winter hibernation. Some fish and frogs quietly freezes into ice, and then, when the temperature rises, thawed and live.

Biologists who study this interesting phenomenon, believe that these animals are able to create in your body natural "anti-freeze", which lowers the freezing point of water. Fish such natural antifreeze are certain proteins, frogs - glucose. Enriching the blood of these proteins, fish can live in the winter in the Arctic at a temperature of 2 degrees C. Frogs have developed the ability to maintain a high level of glucose, thus preventing the formation of ice crystals. Outside their bodies may appear to be frozen through, but actually inside they do not freeze; all bodies retain the ability to function, albeit at a slow rate.

But with mammals, all is not so simple. Freezing of the human body inside the cells begin to form ice crystals. With the growth they pierce and destroy the walls of the cell. (Perhaps celebrities, who wanted to keep their head and body after death frozen in liquid nitrogen would have more time to think.)

However, recently there has been some progress in the work with mammals, which in nature do not hibernate, with other animals such as mice and dogs. In 2005, scientists from the University of Pittsburgh, managed to bring back to life the dogs after both of them were completely emptied of blood and replaced it with a special very cold liquids. After the state of clinical death three hours, dogs revived as soon as they again launched a heart. (Although most dogs after this procedure remained healthy, at some brain was damaged.)

In the same year, scientists put mice in a chamber filled with hydrogen sulphide and have successfully reduced to 6 hours the temperature of their bodies up to 13o S. metabolic Rate mice decreased by ten times. In 2006 the doctors from the Main Massachusetts hospital in Boston introduced mice and pigs in a state of slow life, or animation, also with the help of hydrogen sulfide.

In the future this procedure, quite possibly, would save the lives of victims of serious accidents or from a heart attack, i.e. in those cases when every second counts. It is possible that the animation will give doctors a chance to "stop time", and the patients to wait for the necessary assistance. But it will be decades before this technique can be applied to the astronauts-the people, the more that they might have to spend in suspended animation for more than one century.
Nanakorobi

There are several ways until tested and known only in theory, which in principle can give us the opportunity to reach the stars. One of the most promising proposals - send to SVTDAM unmanned probes, created with the use of nanotechnology. All the previous discussion was based on the assumption that the spaceship must be monstrous machines that consume huge amounts of energy and is able to carry to the stars great crew; like the starship enterprise in the TV series "Star trek".

But much more realistic different path of development. Wiser probably first be sent to distant stars miniature probes with the speeds close to the speed of light. As we have already mentioned, in the future, with the development of nanotechnology, it should be possible to create tiny spaceships, which will include machine atomic and molecular dimensions. For example, ions have an extremely low weight, so they can easily be accelerated to speeds close to the speed of light, this will be enough for the normal electrical network, which can be found in any laboratory. To send into space ions at nearly light speed, no need to build a giant rocket launch, enough to disperse them with powerful electromagnetic field. This means that, if you put ionized nanobots in an electric field, it can easily be accelerated to relativistic speeds. After that nanobots already own will travel to the stars, because in space there is no friction and brake it will be nothing. In this way, many problems are solved, inevitable for large spaceships. It is not excluded that send to the nearest stars smart unmanned ships nanobots will be many times cheaper than to build and run a huge spaceship with a crew of people.

Nanakorobi can be directed to the nearest stars or, as suggested by Gerald Nordli, a retired engineer, air force in Astronautics, be used to create pressure on solar sail and additional its acceleration. Nordli says: "If the whole constellation of ships the size of a pinhead will fly the line and to communicate, it will be possible to break up literally a flashlight".

But Nesvetaylov can discover their problems. So, in open space, they may go astray from exposure to electric and magnetic fields. To prevent this, they will advance, even on Earth, to charge up to a high potential; in this case they will not be so easily led astray. Secondly, we may need to send more than one million vehicles-nanobots that at least a handful of them could guaranteed to reach the goal. It may seem that send for analysis of the nearest stars swarms of nano-spaceships very wasteful, but a spaceship, these must be cheap and mass auto manufacture, probably, will allow to produce their billions; to goal will fly only a small part of the running of the machine".

Can you say how it will look nanakorobi? Daniel Goldin, the former head of NASA, imagined flotilla of spacecraft about the size of the Bank of Coca-Cola. Others talked about ships the size of a needle. The Pentagon is studying the possibility of creation of "smart dust" - small dust-like devices with tiny sensors that could be sprayed over the battlefield, and to continually provide commanders with reliable information. It is not excluded that in the future such "smart dust" can be sent to the nearest stars.

Most likely, the electrical circuit pulverized nanobots will be produced using the same technology of etching, which is used in the manufacture of semiconductors; this technology allows you to create electronic components by size not more than 30 nanometers, or about 150 atoms across. The nanobots can be run from the moon by means of rail guns or even using particle accelerators that are easily dispersed elementary particles up to relativistic velocities. The nanobots have to be so cheap that space can run in the millions.

When they reached the nearest star system, nanobots could take some deserted moon. Gravity her small, and nanobots will be able to land and take off. The dead moon, as a rule, nothing happens, and stable atmosphere ideal for creating a base of operations. Based on the satellite, nanobots will be able to build local materials the nanofactory and to build a powerful radio station, able to send a powerful beam and transmit information to Earth. Nanofactory can also be designed to produce millions of copies of itself nanobot for a detailed study of this star system and flight to the nearest stars. Thus, the process will be repeated. Automatic spaceships there is no need to come back; it is enough for them to transmit to Earth the information collected.

Just described nanobots sometimes referred to as a probe of von Neumann in honour of the famous mathematician, John von Neumann, who developed the mathematical apparatus of self-replicating machines Turing. In principle, such a self-replicating spacecraft-the nanobots are able to explore the entire Galaxy, not just nearby stars. Over time could be formed sphere of trillion of these robots, which exponentially multiplied would at least increase the radius of the sphere; and to extend this would with a velocity close to light speed. For a few hundred thousand years, the nanobots within this expanding sector colonized the entire Galaxy.

Very seriously the idea of Nesvetaylov applies, for example, an electrical engineer Brian Gilchrist from the University of Michigan. Recently he has received from the Institute for advanced concepts NASA grant of $ 500,000. at the elaboration of the idea of construction of nanocarblab with the engine not larger than bacteria. He hopes to use the same technology of etching borrowed from the semiconductor industry to create a fleet of several million nanocarblab. To move these ships will be by throwing tiny nanoparticle size of only a few tens of nanometers. These nanoparticles are expected to accelerate in the electric field is exactly the same as is done in the ion engine. But each nanoparticle weighs thousands of times greater than Jonah, so pull the engines will be significantly more than conventional ionic. Thus, the engines nanocarblab will have all the advantages of ion engines, but much greater thrust. Gilchrist already started to poison some details for their nanocarblab. At the moment he is able to accommodate 10 000 individual "engines" on a single silicon chip size of one centimeter. Initially he plans to send its fleet in the Solar system, and thus to test the effectiveness of nanocarblab. But over time, they can be part of the first earth fleet, which will go to the stars.

Project of L - one of several futuristic proposals that are currently reviewing NASA. After decades of inaction NASA turned again to various projects of interstellar travel - from the very real to absolutely fantastic. Since the early 1990s NASA plays host to the annual research Workshop on advanced space engines, during which several teams serious engineers and physicists dismantle the proposed projects bones. Even more serious are the goals of the program breakthrough physical principles, the aim of which is to explore the mysterious world of quantum physics in the Annex to the idea of interstellar travel. Scientists are not agreed, but for the most part, their efforts are focused on the most successful and advanced at the moment projects: laser sail and different versions of fusion engines.

Given the slow but steady progress in the development of the spacecraft, it is reasonable to assume that the first unmanned probe of certain varieties can go to the nearest stars in this century, or perhaps early next, and then journey to the stars should be classified as the inability of the I class.

However, the most promising probably a variant of the star ship involves the use of antimatter. Currently, this project is more like science fiction, but let's not forget that the antimatter already received on Earth, it is possible that someday in a spaceship that will be the most promising option to send to the stars one of this expedition.