One of the greatest assets of mankind is the international space station, or ISS. Several states united for its creation and operation in orbit: Russia, some European countries, Canada, Japan and the USA. This apparatus testifies that much can be achieved if countries constantly cooperate. All the people of the planet know about this station, and many are wondering at what altitude the ISS flies and in what orbit. How many astronauts have been there? Is it true that tourists are allowed there? And this is not all that is interesting to mankind.
Station structure
The ISS consists of fourteen modules, which contain laboratories, warehouses, rest rooms, bedrooms, utility rooms. The station even has a gym with exercise equipment. The whole complex is solar powered. They are huge, the size of a stadium.
Facts about the ISS
During its work, the station caused a lot of admiration. This apparatus is the greatest achievement of human minds. By its design, purpose and features, it can be called perfection. Of course, maybe in 100 years on Earth they will begin to build spaceships of a different plan, but so far, today, this apparatus is the property of mankind. This is evidenced by the following facts about the ISS:
- During its existence, about two hundred astronauts have visited the ISS. There were also tourists who simply flew in to look at the Universe from an orbital height.
- The station is visible from Earth with the naked eye. This structure is the largest among artificial satellites, and it can be easily seen from the surface of the planet without any magnifying device. There are maps on which you can see at what time and when the device flies over the cities. Using them, it is easy to find information about your locality: see the flight schedule over the region.
- To assemble the station and maintain it in working condition, the astronauts went out more than 150 times in outer space having spent about a thousand hours there.
- The apparatus is operated by six astronauts. The life support system ensures the continuous presence of people at the station from the moment of its first launch.
- The International Space Station is a unique place where a wide variety of laboratory experiments are carried out. Scientists make unique discoveries in the field of medicine, biology, chemistry and physics, physiology and meteorological observations, as well as in other areas of science.
- The device uses giant solar panels, the size of which reaches the area of the football field with its end zones. Their weight is almost three hundred thousand kilograms.
- Batteries are capable of fully ensuring the operation of the station. Their work is closely monitored.
- The station has a mini-house equipped with two bathrooms and a gym.
- The flight is monitored from Earth. Programs consisting of millions of lines of code have been developed for control.
astronauts
Since December 2017, the ISS crew consists of the following astronomers and astronauts:
- Anton Shkaplerov - ISS-55 commander. He visited the station twice - in 2011-2012 and in 2014-2015. For 2 flights, he lived at the station for 364 days.
- Skeet Tingle - Flight engineer, NASA astronaut. This astronaut has no space flight experience.
- Norishige Kanai is a Japanese astronaut and flight engineer.
- Alexander Misurkin. Its first flight was made in 2013 with a duration of 166 days.
- Makr Vande Hay has no flying experience.
- Joseph Akaba. The first flight was made in 2009 as part of Discovery, and the second flight was carried out in 2012.
earth from space
From outer space, unique views open up to Earth. This is evidenced by photographs, videos of astronauts and cosmonauts. You can see the work of the station, space landscapes if you watch online broadcasts from the ISS station. However, some cameras are turned off due to technical work.
Our reader Nikita Ageev asks: what is the main problem of interstellar flights? The answer, like , will require a large article, although the question can be answered with a single character: c .
The speed of light in a vacuum, c, is about 300,000 kilometers per second and cannot be exceeded. Therefore, it is impossible to reach the stars in less than a few years (light takes 4.243 years to reach Proxima Centauri, so the spacecraft cannot arrive even faster). If we add the time for acceleration and deceleration with a more or less acceptable acceleration for a person, then we get about ten years to the nearest star.
What are the conditions to fly?
And this period is already a significant obstacle in itself, even if we ignore the question "how to accelerate to a speed close to the speed of light." Now there are no spaceships that would allow the crew to live autonomously in space for so long - astronauts are constantly brought fresh supplies from Earth. Usually, a conversation about the problems of interstellar travel begins with more fundamental questions, but we will start with purely applied problems.
Even half a century after Gagarin's flight, engineers could not create a washing machine and a fairly practical shower for spacecraft, and toilets designed for weightlessness break down on the ISS with enviable regularity. A flight to at least Mars (22 light minutes instead of 4 light years) already poses a non-trivial task for plumbing designers: so traveling to the stars will require at least inventing a space toilet with a twenty-year warranty and the same washing machine.
Water for washing, washing and drinking will also have to either be taken with you or reused. As well as air, and food, too, must either be stored or grown on board. Experiments to create a closed ecosystem on Earth have already been carried out, but their conditions are still very different from those in space, at least in the presence of gravity. Mankind knows how to turn the contents of a chamber pot into pure drinking water, but in this case it is required to be able to do it in zero gravity, with absolute reliability and without a truck Supplies: taking a truckload of filter cartridges to the stars is too expensive.
Washing socks and protecting against intestinal infections may seem like too banal, "non-physical" restrictions on interstellar flights - but any experienced traveler will confirm that "little things" like uncomfortable shoes or upset stomach from unfamiliar food on an autonomous expedition can turn into a threat to life.
The solution of even elementary everyday problems requires the same serious technological base as the development of fundamentally new space engines. If on Earth a worn-out gasket in a toilet bowl can be bought at the nearest store for two rubles, then already on a Martian spacecraft it is necessary to provide either a reserve all similar parts, or a three-dimensional printer for the production of spare parts from universal plastic raw materials.
In the US Navy in 2013 in earnest engaged in 3D printing after assessing the time and cost of repairing military equipment using traditional methods in field conditions. The military reasoned that it was easier to print some rare gasket for a helicopter assembly that had been discontinued ten years ago than to order a part from a warehouse on another mainland.
One of Korolev's closest associates, Boris Chertok, wrote in his memoir "Rockets and People" that at some point the Soviet space program was faced with a shortage of plug contacts. Reliable connectors for multicore cables had to be developed separately.
In addition to spare parts for equipment, food, water and air, astronauts will need energy. The energy will be needed by the engine and on-board equipment, so the problem of a powerful and reliable source will have to be solved separately. Solar panels are not suitable, if only because of the distance from the luminaries in flight, radioisotope generators (they feed the Voyagers and New Horizons) do not provide the power required for a large manned spacecraft, and they still have not learned how to make full-fledged nuclear reactors for space.
The Soviet nuclear-powered satellite program was marred by an international scandal following the fall of Kosmos-954 in Canada, as well as a series of failures with less dramatic consequences; similar works in the US they turned back even earlier. Now Rosatom and Roskosmos intend to create a space nuclear power plant, but these are still installations for short flights, and not a long-term journey to another star system.
Perhaps instead of nuclear reactor tokamaks will find application in future interstellar spacecraft. About how difficult it is to at least correctly determine the parameters of a thermonuclear plasma, at the Moscow Institute of Physics and Technology this summer. By the way, the ITER project on Earth is progressing successfully: even those who entered the first year today have every chance to join the work on the first experimental thermonuclear reactor with a positive energy balance.
What to fly?
Ordinary rocket engines are not suitable for acceleration and deceleration of an interstellar spacecraft. Those who are familiar with the mechanics course, which is taught at the Moscow Institute of Physics and Technology in the first semester, can independently calculate how much fuel a rocket will need to reach at least one hundred thousand kilometers per second. For those who are not yet familiar with the Tsiolkovsky equation, we will immediately announce the result - the mass of fuel tanks is significantly higher than the mass of the solar system.
It is possible to reduce the fuel supply by increasing the speed at which the engine ejects the working fluid, gas, plasma, or something else, up to a beam of elementary particles. Currently, plasma and ion thrusters are actively used for flights of automatic interplanetary stations within the solar system or for correcting the orbit of geostationary satellites, but they have a number of other disadvantages. In particular, all such engines give too little thrust, so far they cannot give the ship an acceleration of several meters per second squared.
MIPT Vice-Rector Oleg Gorshkov is one of the recognized experts in the field of plasma engines. Engines of the SPD series are produced at the Fakel Design Bureau, these are serial products for correcting the orbit of communication satellites.
In the 1950s, an engine project was being developed that would use the impulse of a nuclear explosion (Project Orion), but it is far from being a ready-made solution for interstellar flights. Even less developed is the design of the engine, which uses the magnetohydrodynamic effect, that is, it accelerates due to interaction with interstellar plasma. Theoretically, the spacecraft could "suck" the plasma in and throw it back to create jet thrust, but there is another problem here.
How to survive?
Interstellar plasma is primarily protons and helium nuclei, if we consider heavy particles. When moving at speeds of the order of hundreds of thousands of kilometers per second, all these particles acquire energy in megaelectronvolts or even tens of megaelectronvolts - the same amount as the products of nuclear reactions have. The density of the interstellar medium is about one hundred thousand ions per cubic meter, which means that in a second square meter ship skin will receive about 10 13 protons with energies of tens of MeV.
One electron volt, eV,― this is the energy that an electron acquires when flying from one electrode to another with a potential difference of one volt. Light quanta have such energy, and ultraviolet quanta with higher energy are already capable of damaging DNA molecules. Radiation or particles with energies in megaelectronvolts accompanies nuclear reactions and, in addition, is itself capable of causing them.
Such irradiation corresponds to an absorbed energy (assuming that all the energy is absorbed by the skin) of tens of joules. Moreover, this energy will come not just in the form of heat, but may be partially spent on initiating nuclear reactions in the material of the ship with the formation of short-lived isotopes: in other words, the skin will become radioactive.
Part of the incident protons and helium nuclei can be deflected to the side by a magnetic field, a complex shell of many layers can be protected from induced radiation and secondary radiation, but these problems also have not yet been solved. In addition, the fundamental difficulties of the form "what material will be least destroyed by irradiation" at the stage of servicing the ship in flight will turn into particular problems - "how to unscrew four bolts by 25 in a compartment with a background of fifty millisieverts per hour."
Recall that during the last repair of the Hubble telescope, the astronauts at first failed to unscrew the four bolts that fastened one of the cameras. After conferring with Earth, they replaced the torque wrench with a regular wrench and applied brute force. The bolts started to move, the camera was successfully replaced. If the stuck bolt had been torn off at the same time, the second expedition would have cost half a billion US dollars. Or it wouldn't have happened at all.
Are there workarounds?
In science fiction (often more fantasy than science), interstellar travel is accomplished through "subspace tunnels". Formally, Einstein's equations, which describe the geometry of space-time depending on the mass and energy distributed in this space-time, do allow something similar - only the estimated energy costs are even more depressing than estimates of the amount of rocket fuel for a flight to Proxima Centauri. Not only is a lot of energy needed, but also the energy density must be negative.
The question of whether it is possible to create a stable, large and energetically possible " wormhole» - is tied to fundamental questions about the structure of the Universe as a whole. One of the unsolved physical problems is the lack of gravity in the so-called standard model- theory describing the behavior of elementary particles and three of the four fundamental physical interactions. The vast majority of physicists are rather skeptical that there is a place for interstellar “jumps through hyperspace” in the quantum theory of gravity, but, strictly speaking, no one forbids trying to look for a workaround for flights to the stars.
Space exploration has long been a common thing for mankind. But flights to near-Earth orbit and to other stars are unthinkable without devices that allow you to overcome the earth's gravity - rockets. How many of us know: how the launch vehicle is arranged and functions, where the launch comes from and what is its speed, which allows to overcome the gravity of the planet even in airless space. Let's take a closer look at these issues.
Device
To understand how a launch vehicle works, you need to understand its structure. Let's start the description of nodes from top to bottom.
CAC
An apparatus that puts a satellite into orbit or a cargo compartment always differs from the carrier, which is intended for transporting the crew, by its configuration. The latter has a special emergency rescue system at the very top, which serves to evacuate the compartment from astronauts in the event of a failure of the launch vehicle. This non-standard shape the turret, located at the very top, is a miniature rocket that allows you to "pull" the capsule with people up under extraordinary circumstances and move it to a safe distance from the point of failure. This is relevant in the initial stage of the flight, where it is still possible to parachute the capsule. In space, the role of the SAS becomes less important.In near-Earth space, the function that makes it possible to separate the descent vehicle from the launch vehicle will allow astronauts to be saved.
cargo compartment
Below the SAS there is a compartment carrying the payload: a manned vehicle, a satellite, a cargo compartment. Based on the type and class of the launch vehicle, the mass of the cargo put into orbit can range from 1.95 to 22.4 tons. All cargo transported by the ship is protected by a head fairing, which is dropped after passing through the atmospheric layers.
sustainer engine
Far from outer space, people think that if the rocket was in a vacuum, at a height of one hundred kilometers, where weightlessness begins, then its mission is over. In fact, depending on the task, the target orbit of the cargo being launched into space can be much further. For example, telecommunications satellites need to be transported to an orbit located at an altitude of more than 35 thousand kilometers. To achieve the necessary removal, a sustainer engine is needed, or, as it is called in another way, an accelerating unit. To enter the planned interplanetary or departure trajectory, one should change the flight speed more than once, performing certain actions, therefore this engine must be started and turned off repeatedly, this is its dissimilarity with other similar rocket components.
Multistage
In a launch vehicle, only a small fraction of its mass is occupied by the transported payload, everything else is engines and fuel tanks, which are located in different stages of the vehicle. The design feature of these units is the possibility of their separation after the fuel is used up. Then they burn up in the atmosphere before reaching the ground. True, according to the reactor.space news portal, in last years a technology was developed that allows returning the separated steps unharmed to the point allotted for this and re-launching them into space. In rocket science, when creating multi-stage ships, two schemes are used:
- The first one, longitudinal, allows you to place several identical engines with fuel around the hull, which are simultaneously switched on and synchronously reset after use.
- The second - transverse, makes it possible to arrange steps in ascending order, one above the other. In this case, their inclusion occurs only after resetting the lower, exhausted stage.
But often designers prefer a combination of a transverse-longitudinal pattern. A rocket can have many stages, but increasing their number is rational up to a certain limit. Their growth entails an increase in the mass of engines and adapters that operate only at a certain stage of flight. Therefore, modern launch vehicles are not equipped with more than four stages. Basically, the fuel tanks of the stages consist of reservoirs in which various components are pumped: an oxidizer (liquid oxygen, nitrogen tetroxide) and fuel (liquid hydrogen, heptyl). Only with their interaction can the rocket be accelerated to the desired speed.
How fast does a rocket fly in space?
Depending on the tasks that the launch vehicle must perform, its speed may vary, subdivided into four values:
- First space. It allows you to rise into orbit where it becomes a satellite of the Earth. If translated into the usual values, it is equal to 8 km / s.
- Second space. Speed at 11.2 km / s. makes it possible for the ship to overcome gravity for the study of the planets of our solar system.
- Third space. Adhering to the speed of 16.650 km/s. it is possible to overcome the gravity of the solar system and leave its limits.
- Fourth space. Having developed a speed of 550 km / s. the rocket is capable of flying out of the galaxy.
But no matter how great the speed of spacecraft, they are too small for interplanetary travel. With such values, it will take 18,000 years to get to the nearest star.
What is the name of the place where rockets are launched into space?
For the successful conquest of space, special launch pads are needed, from where rockets can be launched into outer space. In everyday use they are called spaceports. But this simple name includes a whole complex of buildings that occupies vast territories: the launch pad, the premises for the final test and assembly of the rocket, the buildings of related services. All this is located at a distance from each other, so that other structures of the cosmodrome would not be damaged in the event of an accident.
Conclusion
The more space technologies improve, the more complex the structure and operation of the rocket becomes. Maybe in a few years, new devices will be created to overcome the gravity of the Earth. And the next article will be devoted to the principles of operation of a more advanced rocket.
Modern technologies and discoveries are taking space exploration to a completely different level, but interstellar travel is still a dream. But is it so unrealistic and unattainable? What can we do now and what can we expect in the near future?
By studying data from the Kepler telescope, astronomers have discovered 54 potentially habitable exoplanets. These distant worlds are in the habitable zone, ie. at a certain distance from the central star, which allows maintaining liquid water on the surface of the planet.
However, the answer to the main question, are we alone in the Universe, is difficult to get - because of the huge distance separating the solar system and our nearest neighbors. For example, the "promising" planet Gliese 581g is 20 light-years away - close enough by cosmic standards, but still too far for terrestrial instruments.
The abundance of exoplanets within a radius of 100 or less light-years from Earth and the enormous scientific and even civilizational interest that they represent for mankind make us take a fresh look at the hitherto fantastic idea of interstellar flights.
Flying to other stars is, of course, a matter of technology. Moreover, there are several possibilities for achieving such a distant goal, and the choice in favor of one or another method has not yet been made.
Mankind has already sent interstellar vehicles into space: the Pioneer and Voyager probes. At present, they have left the solar system, but their speed does not allow us to talk about any quick achievement of the goal. So, Voyager 1, moving at a speed of about 17 km / s, even to the nearest star Proxima Centauri (4.2 light years) will fly incredibly long term- 17 thousand years.
Obviously, with modern rocket engines, we will not get anywhere further than the solar system: to transport 1 kg of cargo, even to the nearby Proxima Centauri, tens of thousands of tons of fuel are needed. At the same time, with an increase in the mass of the ship, the amount of fuel required increases, and additional fuel is needed for its transportation. A vicious circle that puts an end to chemical fuel tanks - the construction of a spacecraft weighing billions of tons seems to be an absolutely incredible undertaking. Simple Calculations using the Tsiolkovsky formula demonstrate that to accelerate chemical-fueled spacecraft to about 10% of the speed of light, more fuel is required than is available in the known universe.
A fusion reaction produces energy per unit mass, on average, a million times more than chemical processes combustion. That is why, in the 1970s, NASA drew attention to the possibility of using thermonuclear rocket engines. The project of the unmanned spacecraft Daedalus involved the creation of an engine in which small pellets of thermonuclear fuel would be fed into the combustion chamber and ignited by electron beams. The products of a thermonuclear reaction fly out of the engine nozzle and give the ship acceleration.
The Daedalus spaceship compared to the Empire State Building
Daedalus was supposed to take on board 50 thousand tons fuel pellets 4 and 2 mm in diameter. The granules consist of a core with deuterium and tritium and a shell of helium-3. The latter makes up only 10-15% of the mass of the fuel pellet, but, in fact, is the fuel. Helium-3 is abundant on the Moon, and deuterium is widely used in the nuclear industry. The deuterium core serves as a detonator to ignite the fusion reaction and provokes a powerful reaction with the release of a reactive plasma jet, which is controlled by a powerful magnetic field. The main molybdenum combustion chamber of the Daedalus engine was supposed to have a weight of more than 218 tons, the second stage chamber - 25 tons. Magnetic superconducting coils are also a match for a huge reactor: the first weighs 124.7 tons, and the second - 43.6 tons. For comparison: the dry weight of the shuttle is less than 100 tons.
The flight of Daedalus was planned to be two-stage: the first stage engine was supposed to work for more than 2 years and burn 16 million fuel pellets. After the separation of the first stage, the second stage engine worked for almost two years. Thus, in 3.81 years of continuous acceleration, Daedalus would have reached a maximum speed of 12.2% of the speed of light. The distance to Barnard's Star (5.96 light-years) will be overcome by such a ship in 50 years and will be able, flying through a distant star system, to transmit the results of its observations by radio to Earth. Thus, the entire mission will take about 56 years.
Despite the great difficulties in ensuring the reliability of numerous Daedalus systems and its huge cost, this project is being implemented on modern level technologies. Moreover, in 2009 a team of enthusiasts revived work on the project of a thermonuclear ship. Currently, the Icarus project includes 20 scientific topics on the theoretical development of systems and materials for an interstellar spacecraft.
Thus, unmanned interstellar flights up to 10 light-years away are already possible today, which will take about 100 years of flight plus the time for the radio signal to travel back to Earth. The star systems Alpha Centauri, Barnard's Star, Sirius, Epsilon Eridani, UV Ceti, Ross 154 and 248, CN Leo, WISE 1541-2250 fit into this radius. As you can see, there are enough objects near the Earth to study with the help of unmanned missions. But what if robots find something really unusual and unique, like a complex biosphere? Will an expedition involving people be able to go to distant planets?
Flight of a lifetime
If we can start building an unmanned ship today, then with a manned one, the situation is more complicated. First of all, the issue of flight time is acute. Let's take the same Barnard's star. Cosmonauts will have to be prepared for a manned flight from school, because even if the launch from Earth takes place on their 20th birthday, the ship will reach the flight goal by the 70th or even 100th anniversary (given the need for braking, which is not needed in an unmanned flight) . Crew selection at a young age is fraught with psychological incompatibility and interpersonal conflicts, and the age of 100 does not give hope for fruitful work on the surface of the planet and for returning home.
However, does it make sense to return? Numerous NASA studies lead to a disappointing conclusion: a long stay in zero gravity will irreversibly destroy the health of astronauts. Thus, the work of biology professor Robert Fitts with ISS astronauts shows that even despite vigorous physical exercise on board the spacecraft, after a three-year mission to Mars, large muscles, such as calves, will become 50% weaker. Similarly, bone mineral density also decreases. As a result, the ability to work and survival in extreme situations decreases significantly, and the period of adaptation to normal gravity will be at least a year. Flying in zero gravity for decades will call into question the very lives of astronauts. Perhaps the human body will be able to recover, for example, in the process of braking with gradually increasing gravity. However, the risk of death is still too high and requires a radical solution.
Stanford Tor is a colossal structure with entire cities inside a rotating rim.
Unfortunately, it is not so easy to solve the problem of weightlessness on an interstellar spacecraft. The possibility available to us to create artificial gravity by rotating the habitable module has a number of difficulties. To create earth's gravity, even a wheel with a diameter of 200 m will have to be rotated at a speed of 3 revolutions per minute. With such a rapid rotation, the Cariolis force will create loads that are completely unbearable for the human vestibular apparatus, causing nausea and acute attacks of seasickness. The only solution to this problem is the Stanford Tor, developed by scientists at Stanford University in 1975. This is a huge ring with a diameter of 1.8 km, in which 10 thousand cosmonauts could live. Due to its size, it provides a gravity of 0.9-1.0 g and is quite comfortable accommodation of people. However, even at rotation speeds lower than one revolution per minute, people will still experience mild but noticeable discomfort. Moreover, if such a gigantic living compartment is built, even small shifts in the weight distribution of the torus will affect the rotation speed and cause vibrations of the entire structure.
The problem of radiation remains complex. Even near the Earth (on board the ISS), astronauts spend no more than six months because of the danger of radiation exposure. The interplanetary ship will have to be equipped with heavy protection, but the question of the effect of radiation on the human body remains. In particular, on the risk of oncological diseases, the development of which in weightlessness is practically not studied. Earlier this year, scientist Krasimir Ivanov of the German Aerospace Center in Cologne published the results of an interesting study of the behavior of melanoma cells (the most dangerous form of skin cancer) in zero gravity. Compared to cancer cells grown under normal gravity, cells that have spent 6 and 24 hours in weightlessness are less likely to metastasize. This seems to be good news, but only at first glance. The fact is that such a “space” cancer can lie dormant for decades, and unexpectedly spread on a large scale if the immune system is disrupted. In addition, the study makes it clear that we still know little about the reaction of the human body to a long stay in space. Astronauts today, healthy strong people, spend too little time there to transfer their experience to a long interstellar flight.
In any case, a ship for 10 thousand people is a dubious undertaking. To create a reliable ecosystem for such a large number of people, you need a huge number of plants, 60 thousand chickens, 30 thousand rabbits and a herd of cattle. Only this can provide a diet at the level of 2400 calories per day. However, all experiments to create such closed ecosystems invariably end in failure. Thus, in the course of the largest experiment "Biosphere-2" by Space Biosphere Ventures, a network of hermetic buildings was built with total area 1.5 hectares with 3 thousand species of plants and animals. The whole ecosystem was supposed to become a self-sustaining little "planet" in which 8 people lived. The experiment lasted 2 years, but after a few weeks serious problems began: microorganisms and insects began to multiply uncontrollably, consuming oxygen and plants in too much large quantities, it also turned out that without wind, the plants became too fragile. As a result of a local environmental catastrophe, people began to lose weight, the amount of oxygen decreased from 21% to 15%, and the scientists had to violate the conditions of the experiment and supply oxygen and food to eight “cosmonauts”.
Thus, the creation of complex ecosystems seems to be an erroneous and dangerous way to provide the crew of an interstellar spacecraft with oxygen and nutrition. Solving this problem will require specially engineered organisms with altered genes that can feed on light, waste and simple substances. For example, large modern plants for the production of chlorella food algae can produce up to 40 tons of suspension per day. One completely autonomous bioreactor weighing several tons can produce up to 300 liters of chlorella suspension per day, which is enough to feed a crew of several dozen people. Genetically modified chlorella could not only meet the nutritional needs of the crew, but also process waste, including carbon dioxide. Today, the process of genetic engineering of microalgae has become commonplace, and there are numerous designs developed for purification. Wastewater, biofuel production, etc.
Frozen dream
Almost all of the above problems of manned interstellar flight could be solved by one very promising technology - suspended animation, or as it is also called cryostasis. Anabiosis is a slowdown of human life processes at least several times. If it is possible to immerse a person in such an artificial lethargy, which slows down the metabolism by 10 times, then in a 100-year flight he will grow old in his sleep by only 10 years. This facilitates the solution of problems of nutrition, oxygen supply, mental disorders, destruction of the body as a result of weightlessness. In addition, it is easier to protect a compartment with suspended animation chambers from micrometeorites and radiation than a large habitable zone.
Unfortunately, slowing down the processes of human life is extremely difficult task. But in nature, there are organisms that can hibernate and increase their life expectancy hundreds of times. For example, a small lizard called the Siberian salamander is able to hibernate in difficult times and stay alive for decades, even when frozen into a block of ice with a temperature of minus 35-40 ° C. There are cases when salamanders hibernated for about 100 years and, as if nothing had happened, thawed and ran away from surprised researchers. At the same time, the usual "continuous" life expectancy of a lizard does not exceed 13 years. The amazing ability of the salamander is explained by the fact that its liver synthesizes a large amount of glycerol, almost 40% of its body weight, which protects cells from low temperatures.
The main obstacle to immersing a person in cryostasis is water, which makes up 70% of our body. When it freezes, it turns into ice crystals, increasing in volume by 10%, due to which the cell membrane breaks. In addition, as it freezes, substances dissolved inside the cell migrate into the remaining water, disrupting intracellular ion exchange processes, as well as the organization of proteins and other intercellular structures. In general, the destruction of cells during freezing makes it impossible for a person to return to life.
However, there is a promising way to solve this problem - clathrate hydrates. They were discovered back in 1810, when the British scientist Sir Humphry Davy injected chlorine under high pressure into the water and witnessed the formation of solid structures. These were clathrate hydrates - one of the forms of water ice, in which foreign gas is included. Unlike ice crystals, clathrate lattices are less hard, do not have sharp edges, but have cavities in which intracellular substances can “hide”. The technology of clathrate suspended animation would be simple: an inert gas, such as xenon or argon, a temperature just below zero, and cellular metabolism begins to gradually slow down until a person falls into cryostasis. Unfortunately, the formation of clathrate hydrates requires high pressure (about 8 atmospheres) and a very high concentration of gas dissolved in water. How to create such conditions in a living organism is still unknown, although there are some successes in this area. Thus, clathrates are able to protect heart muscle tissue from destruction of mitochondria even at cryogenic temperatures (below 100 degrees Celsius), as well as prevent damage to cell membranes. Experiments on clathrate anabiosis in humans are not yet discussed, since the commercial demand for cryostasis technology is small and research on this topic is carried out mainly by small companies offering services for freezing the bodies of the dead.
Flight on hydrogen
In 1960, physicist Robert Bassard proposed the original concept of a ramjet fusion engine that solves many of the problems of interstellar travel. The bottom line is to use the hydrogen and interstellar dust present in outer space. A spacecraft with such an engine first accelerates on its own fuel, and then unfolds a huge funnel of a magnetic field, thousands of kilometers in diameter, which captures hydrogen from outer space. This hydrogen is used as an inexhaustible source of fuel for a fusion rocket engine.
The use of the Bussard engine promises enormous advantages. First of all, due to the "gratuitous" fuel, it is possible to move with a constant acceleration of 1 g, which means that all the problems associated with weightlessness disappear. In addition, the engine allows you to accelerate to tremendous speed - 50% of the speed of light and even more. Theoretically, moving with an acceleration of 1 g, a ship with a Bussard engine can cover a distance of 10 light years in about 12 Earth years, and for the crew, due to relativistic effects, only 5 years of ship time would have passed.
Unfortunately, there are a number of serious problems on the way to creating a ship with a Bussard engine that cannot be solved at the current level of technology. First of all, it is necessary to create a giant and reliable hydrogen trap that generates magnetic fields gigantic strength. At the same time, it must provide minimum losses and efficient transport of hydrogen to a fusion reactor. The very process of a thermonuclear reaction of the transformation of four hydrogen atoms into a helium atom, proposed by Bussard, raises many questions. The fact is that this simplest reaction is difficult to implement in a once-through reactor, since it proceeds too slowly and, in principle, is possible only inside stars.
However, progress in the study of thermonuclear fusion allows us to hope that the problem can be solved, for example, by using "exotic" isotopes and antimatter as a reaction catalyst.
So far, research on the Bussard engine lies exclusively in the theoretical plane. Calculations based on real technologies are needed. First of all, it is necessary to develop an engine capable of generating enough energy to power a magnetic trap and maintain a thermonuclear reaction, produce antimatter and overcome the resistance of the interstellar medium, which will slow down the huge electromagnetic "sail".
Antimatter to the rescue
It may sound strange, but today humanity is closer to creating an antimatter engine than to the intuitive and simple at first glance Bussard's ramjet engine.
The probe, developed by Hbar Technologies, will have a thin sail made of carbon fiber coated with uranium 238. Crashing into the sail, antihydrogen will annihilate and create jet thrust.
As a result of the annihilation of hydrogen and antihydrogen, a powerful photon flux is formed, the exhaust velocity of which reaches a maximum for a rocket engine, i.e. the speed of light. This is an ideal indicator that allows you to achieve very high near-light speeds of a spacecraft with a photon engine. Unfortunately, it is very difficult to use antimatter as a rocket fuel, since during annihilation flashes of the most powerful gamma radiation occur, which will kill astronauts. Also, there are no storage technologies yet a large number antimatter, and the very fact of the accumulation of tons of antimatter, even in space far from the Earth, is a serious threat, since the annihilation of even one kilogram of antimatter is equivalent to nuclear explosion with a capacity of 43 megatons (an explosion of such force is capable of turning a third of the territory of the United States into a desert). The cost of antimatter is another factor complicating photon-powered interstellar flight. Modern technologies for the production of antimatter make it possible to produce one gram of antihydrogen at a cost of tens of trillions of dollars.
However big projects antimatter research is bearing fruit. At present, special storage facilities for positrons have been created, “magnetic bottles”, which are containers cooled by liquid helium with walls made of magnetic fields. In June of this year, CERN scientists managed to preserve antihydrogen atoms for 2,000 seconds. The world's largest antimatter repository is being built at the University of California (USA), which will be able to accumulate more than a trillion positrons. One of the goals of scientists at the University of California is to create portable containers for antimatter that can be used for scientific purposes away from large accelerators. This project is supported by the Pentagon, which is interested in antimatter military applications, so the world's largest array of magnetic bottles is unlikely to be underfunded.
Modern accelerators will be able to produce one gram of antihydrogen in a few hundred years. This is very long, so the only way out is to develop new technology production of antimatter or unite the efforts of all countries of our planet. But even in this case, modern technologies there is nothing to dream about the production of tens of tons of antimatter for interstellar manned flight.
However, everything is not so sad. NASA specialists have developed several designs for spacecraft that could go into deep space with just one microgram of antimatter. NASA believes that improved equipment will make it possible to produce antiprotons at a cost of about $5 billion per gram.
The American company Hbar Technologies, with the support of NASA, is developing the concept of unmanned probes driven by an antihydrogen engine. The first goal of this project is to create an unmanned spacecraft that could fly to the Kuiper belt at the edge of the solar system in less than 10 years. Today, it is impossible to fly to such remote points in 5-7 years, in particular, the NASA New Horizons probe will fly through the Kuiper belt 15 years after launch.
A probe that travels a distance of 250 AU in 10 years, it will be very small, with a payload of only 10 mg, but it will also need a little antihydrogen - 30 mg. The Tevatron will produce this amount in a few decades, and scientists could test the concept of a new engine during a real space mission.
Preliminary calculations also show that a small probe can be sent to Alpha Centauri in a similar way. On one gram of antihydrogen, it will fly to a distant star in 40 years.
It may seem that all of the above is fiction and has nothing to do with the near future. Fortunately, this is not the case. While public attention is riveted to global crises, pop star failures and other current events, epoch-making initiatives remain in the shadows. The NASA space agency launched the grandiose 100 Year Starship project, which involves the gradual and multi-year creation of a scientific and technological foundation for interplanetary and interstellar flights. This program is unique in the history of mankind and should attract scientists, engineers and enthusiasts of other professions from all over the world. From September 30 to October 2, 2011, a symposium will be held in Orlando, Florida, where various space flight technologies will be discussed. Based on the results of such events, NASA specialists will develop a business plan to assist certain industries and companies that are developing technologies that are not yet available, but necessary for future interstellar flight. If NASA's ambitious program is successful, within 100 years humanity will be able to build an interstellar spacecraft, and solar system we will move with the same ease as we fly from mainland to mainland today.
