Alcubierre

Anything called "warp drive" sounds more like Star Trek than NASA. The idea behind the Alcubierre warp drive is that it can be possible solution(or at least the beginning of his search) of the task of overcoming the limitations of the universe that it imposes on travel faster than the speed of light.

The basics of this idea are quite simple, and NASA uses the example of a treadmill to explain it. Although a person may be moving at a finite speed on a treadmill, the combined speed of the person and the treadmill means that the end will be closer than it would be on a regular treadmill. The treadmill is precisely a warp engine moving through space-time in a kind of expansion bubble. In front of the warp drive, spacetime is compressed. Behind him it expands. In theory, this allows the engine to propel passengers faster than the speed of light. One of key principles, associated with the expansion of spacetime, is believed to have allowed the Universe to rapidly expand moments after the Big Bang. In theory, the idea should be quite feasible.

It's terrible when there is no Internet on Earth and you can't download Google Maps on your smartphone. During interstellar flights without it it will be even worse. Getting into space is just the first step; scientists are already starting to wonder what to do when our manned and unmanned probes need to transmit messages back to Earth.

In 2008, NASA conducted the first successful tests of an interstellar version of the Internet. The project was launched back in 1998 as part of a partnership between the Laboratory jet propulsion NASA (JPL) and Google. Ten years later, the partners had a Disruption-Tolerant Networking (DTN) system, which allows them to send images to a spacecraft 30 million kilometers away.

The technology must be able to cope with long delays and interruptions in transmissions, so it can continue transmitting even if the signal is interrupted for 20 minutes. It can pass through, between, or through everything from solar flares and solar storms to pesky planets that might be in the data path, without losing any information.

According to Vint Cerf, one of the founders of our terrestrial Internet and a pioneer of the interstellar one, the DTN system overcomes all the problems that plague the traditional TCIP/IP protocol when it needs to operate over long distances on a cosmic scale. With TCIP/IP, a Google search on Mars will take so long that the results will change while the query is being processed, and some of the information will be lost on the output. With DTN, the engineers added something completely new - the ability to assign different domain names to different planets and choose which planet you want to search the Internet on.

What about traveling to planets we are not yet familiar with? Scientific American suggests that there may be a way, albeit a very expensive and time-consuming one, to bring internet to Alpha Centauri. By launching a series of self-replicating von Neumann probes, it is possible to create a long series of relay stations that can send information along the interstellar circuit. A signal born in our system will travel through the probes and reach Alpha Centauri, and vice versa. True, many probes will be required, the construction and launch of which will cost billions. And in general, given that the farthest probe will have to travel its path for thousands of years, it can be assumed that during this time not only technologies will change, but also the overall cost of the event. Let's not rush.

Embryonic colonization of space

One of the biggest problems with interstellar travel - and colonization in general - is the amount of time it takes to get anywhere, even with some warp drives up your sleeve. The very task of delivering a group of settlers to their destination gives rise to a lot of problems, so proposals are born to send not a group of colonists with a fully staffed crew, but rather a ship filled with embryos - the seeds of the future of humanity. Once the ship reaches the required distance to its destination, the frozen embryos begin to grow. Then they come out with children who grow up on the ship, and when they finally reach their destination, they have all the abilities to conceive a new civilization.

Obviously, all this, in turn, raises a huge pile of questions, such as who will carry out the cultivation of embryos and how. Robots could raise people, but what will the people raised by robots be like? Will robots be able to understand what a child needs to grow and thrive? Will they be able to understand punishments and rewards, human emotions? And in general, it remains to be seen how to keep frozen embryos intact for hundreds of years and how to grow them in an artificial environment.

One proposed solution that could solve the problems of a robot nanny would be to create a combination of a ship with embryos and a ship with suspended animation in which adults sleep, ready to wake up when they have to raise children. A succession of years of child rearing coupled with a return to hibernation could, in theory, lead to a stable population. A carefully created batch of embryos can provide the genetic diversity that will allow the population to be maintained in a more or less stable state once a colony is established. An additional batch can also be included in a ship with embryos, which will further diversify the genetic pool.

Von Neumann probes

Everything we build and send into space inevitably comes with its own challenges, and making something that will travel millions of miles without burning up, falling apart, or fading away seems like a completely impossible task. However, the solution to this problem may have been found decades ago. In the 1940s, physicist John von Neumann proposed mechanical technology, which will be reproduced, and although his idea had nothing to do with interstellar travel, everything inevitably came to this. As a result, von Neumann probes could, in theory, be used to explore vast interstellar regions. According to some researchers, the idea that all this came to us first is not only pompous, but also unlikely.

Scientists from the University of Edinburgh published a paper in the International Journal of Astrobiology, which explored not only the possibility of creating such technology for their own needs, but also the likelihood that someone has already done it. Based on previous calculations that showed how far a craft could travel using different modes of propulsion, the scientists studied how this equation would change when applied to self-replicating craft and probes.

Scientists' calculations centered around self-replicating probes that could use debris and other space materials to build junior probes. The parent and daughter probes would multiply so quickly that they would cover the entire galaxy in just 10 million years - and that's if they were traveling at 10% the speed of light. However, this would mean that at some point we should have been visited by some similar probes. Since we haven't seen them, a convenient explanation can be found: either we are not technologically advanced enough to know where to look, or .

Slingshot with black hole

The idea of ​​using the gravity of a planet or moon to shoot, like from a slingshot, was adopted in our solar system more than once or twice, most notably by Voyager 2, which received an additional push first from Saturn, and then from Uranus on its way out of the system . The idea involves maneuvering the ship, allowing it to increase (or decrease) its speed as it moves through the planet's gravitational field. Science fiction writers especially love this idea.

Writer Kip Thorne put forward an idea: such a maneuver could help the device solve one of the biggest problems of interstellar travel - fuel consumption. And he proposed a more risky maneuver: acceleration using binary black holes. It will take a minute of burning fuel to get through the critical orbit from one black hole to another. After making several revolutions around black holes, the device will gain speed close to light. All that remains is to aim well and activate the rocket thrust to set yourself a course to the stars.

Unlikely? Yes. Marvelous? Definitely. Thorne points out that there are many problems with such an idea, such as accurate calculations of trajectories and timing, which would prevent the device from being sent directly to the nearest planet, star or other body. Questions also arise about returning home, but if you decide on such a maneuver, you definitely do not plan to return.

A precedent for such an idea has already been established. In 2000, astronomers discovered 13 supernovae flying through the galaxy at an incredible speed of 9 million kilometers per hour. Scientists at the University of Illinois at Urbana-Champagne have discovered that these wayward stars were ejected from the galaxy by a pair of black holes that became locked into a pair during the process of destruction and merger of two separate galaxies.

Starseed Launcher

When it comes to launching even self-replicating probes, fuel consumption becomes an issue. This hasn't stopped people from looking for new ideas on how to launch probes to interstellar distances. This process would require megatons of energy if we used the technology we have today.

Forrest Bishop of the Institute of Atomic Engineering said he has created a method for launching interstellar probes that would require an amount of energy roughly equivalent to that of a car battery. The theoretical Starseed Launcher would be approximately 1,000 kilometers long and consist primarily of wires and wires. Despite its length, the whole thing could fit in one cargo ship and be powered by a 10-volt battery.

Part of the plan involves launching probes that are little more than a microgram in mass and contain only the basic information needed to further build probes in space. Over a series of launches, billions of such probes can be launched. The main gist of the plan is that self-replicating probes will be able to combine with each other after launch. The launcher itself will be equipped with superconducting magnetic levitation coils that create a reverse force that provides thrust. Bishop says that some details of the plan need to be worked out, such as countering interstellar radiation and debris with probes, but in general, construction can begin.

Special plants for space life

Once we get somewhere, we'll need ways to grow food and regenerate oxygen. Physicist Freeman Dyson has proposed some interesting ideas on how this could be done.

In 1972, Dyson gave his famous lecture at Birkbeck College, London. Then he suggested that with the help of some genetic manipulations it would be possible to create trees that could not only grow, but also thrive on an inhospitable surface, like a comet, for example. Reprogram a tree to reflect ultraviolet light and conserve water more efficiently, and the tree will not only take root and grow, but also reach sizes unimaginable by earthly standards. In an interview, Dyson suggested that in the future there might be black trees, both in space and on Earth. Silicon-based trees would be more efficient, and efficiency is the key to longevity. Dyson emphasizes that this process will not be a matter of minutes - perhaps in two hundred years we will finally figure out how to make trees grow in space.

Dyson's idea isn't that outlandish. NASA's Institute for Advanced Concepts is an entire department dedicated to solving the problems of the future, and among them is the task of growing sustainable plants on the surface of Mars. Even greenhouse plants on Mars will grow in extreme conditions, and scientists are trying different options to try to combine plants with extremophiles, tiny microscopic organisms that survive in some of the harshest conditions on Earth. From high-altitude tomatoes that have built-in resistance to ultraviolet light, to bacteria that survive in the coldest, hottest and deepest corners globe, we may one day assemble the pieces of a Martian garden. All that remains is to figure out how to put all these bricks together.

Local resource recycling

Living off the ground may be a new trend on Earth, but when it comes to month-long missions in space, it becomes necessary. Currently, NASA is engaged, among other things, in studying the issue of local resource utilization (ISRU). There is only so much space on a spaceship, and creating systems to utilize materials found in space and on other planets will be necessary for any long-term colonization or travel, especially when the destination is a place where it will be very difficult to deliver cargo of supplies, fuel, food And so on. The first attempts to demonstrate the possibilities of using local resources were made on the slopes of Hawaiian volcanoes and during polar missions. The list of tasks includes such items as extracting fuel components from ashes and other naturally accessible terrain.

In August 2014, NASA made a powerful announcement by revealing new toys that would go to Mars with the next rover, launching in 2020. Among the tools in the new rover's arsenal is MOXIE, an experiment for local resource utilization in the form of Martian oxygen. MOXIE will take Mars' unbreathable atmosphere (96% carbon dioxide) and split it into oxygen and carbon monoxide. The device will be able to produce 22 grams of oxygen for every hour of operation. NASA also hopes that MOXIE will be able to demonstrate something else - permanent job without reducing productivity or efficiency. Not only could MOXIE be an important step toward long-term extraterrestrial missions, but it could also pave the way for many potential converters of harmful gases into useful ones.

2suit

Reproduction in space can become problematic on a variety of levels, especially in microgravity. In 2009, Japanese experiments on mouse embryos showed that even if fertilization occurs in non-zero gravity conditions, embryos that develop outside the normal gravity of the Earth (or its equivalent) do not develop normally. When cells must divide and perform specialized activities, problems arise. This does not mean that fertilization does not occur: mouse embryos conceived in space and implanted into female mice on Earth grew successfully and were born without problems.

This also raises another question: How exactly does baby production work in microgravity? The laws of physics, especially the fact that every action has an equal and opposite reaction, make its mechanics a little ridiculous. Vanna Bonta, writer, actress and inventor, decided to take this issue seriously.

And she created 2suit: a suit in which two people can hide and start making babies. They even checked him. In 2008, 2suit was tested on the so-called Vomit Comet (an airplane that makes sharp turns and creates minute-long conditions of weightlessness). While Bonta suggests that honeymoons in space could become a reality thanks to her invention, the suit also has more practical uses, like conserving body heat in an emergency.

Project Longshot

Project Longshot was compiled by a team from the US Naval Academy and NASA as part of a joint effort in the late 1980s. Final goal The plan was to launch something at the turn of the 21st century, namely an unmanned probe that would go to Alpha Centauri. It would take him 100 years to achieve his goal. But before it can be launched, it will need some key components that also need to be developed.

In addition to communications lasers, long-life fission reactors, and inertial laser fusion rocket propulsion, there were other elements. The probe had to be given independent thinking and functions, since it would be virtually impossible to communicate across interstellar distances fast enough for the information to remain relevant once it reached the receiving point. Everything also had to be incredibly durable, since the probe would take 100 years to reach its destination.

Longshot was going to be sent to Alpha Centauri with various tasks. Basically, he had to collect astronomical data that would allow accurate calculations of distances to billions, if not trillions, of other stars. But if the nuclear reactor powering the craft runs out, the mission will also stop. Longshot was a very ambitious plan that never got off the ground.

But this does not mean that the idea died in its infancy. In 2013, the Longshot II project literally got off the ground in the form of the student project Icarus Interstellar. There have been decades of technological advancements since the original Longshot program that can be applied to the new version, and the program as a whole has received an overhaul. Fuel costs were reviewed, mission duration was cut in half and the entire Longshot design was revised from head to toe.

The final project will be an interesting indicator of how an unsolvable problem changes with the addition of new technology and information. The laws of physics remain the same, but 25 years later, Longshot has the opportunity to find a second wind and show us what it should be interstellar travel future.

Based on materials from listverse.com

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?

Using the Kepler telescope, astronomers have already discovered 54 potentially habitable exoplanets. These distant worlds are in the habitable zone, i.e. at a certain distance from the central star, allowing water to be maintained in liquid form on the surface of the planet.

However, the answer to main question Whether we are alone in the Universe is difficult to determine - due to the enormous distance separating the Solar System and our closest neighbors.

For example, the “promising” planet Gliese 581g is located at a distance of 20 light years - this is close enough by cosmic standards, but still too far for terrestrial instruments.

The abundance of exoplanets within a radius of 100 light years or less from Earth and the enormous scientific and even civilizational interest that they represent for humanity force us to take a fresh look at the hitherto fantastic idea of ​​interstellar travel.

Rice. 1. The stars closest to our solar system.

Flight 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 method or another has not yet been made.

Make way for drones

Humanity has already sent interstellar vehicles into space: the Pioneer and Voyager probes. Currently, they have left the solar system, but their speed does not allow us to talk about any rapid achievement of the goal. Thus, Voyager 1, moving at a speed of about 17 km/s, will fly incredibly even to the nearest star Proxima Centauri (4.2 light years) long term– 17 thousand years.

It is obvious that 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, as the mass of the ship increases, the number of required fuel, and additional fuel is needed to transport it. A vicious circle that puts an end to tanks with chemical fuel - the construction of a space vessel weighing billions of tons seems to be an absolutely incredible undertaking. Simple calculations using Tsiolkovsky's formula demonstrate that accelerating chemically propelled spacecraft to about 10% the speed of light would require more fuel than is available in the known universe.

Reaction thermonuclear fusion produces energy per unit mass on average a million times more than chemical combustion processes. That is why in the 1970s NASA turned its attention to the possibility of using thermonuclear rocket engines. The project for the unmanned spacecraft Daedalus involved the creation of an engine in which small granules thermonuclear fuel will be fed into the combustion chamber and ignited by electron beams. The thermonuclear reaction products fly out of the engine nozzle and give the ship acceleration.

Rice. 2. The spaceship Daedalus compared to the Empire State Building.

Daedalus was supposed to take on board 50 thousand tons of fuel pellets with a diameter of 40 and 20 mm. The granules consist of a core containing 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 weigh more than 218 tons, the second stage chamber - 25 tons. Magnetic superconducting coils also match the 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 Daedalus flight was planned to be a two-stage one: the first stage engine was supposed to operate for more than 2 years and burn 16 billion fuel pellets. After the separation of the first stage, the second stage engine operated 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.

Such a ship will cover the distance to Barnard's star (5.96 light years) in 50 years and will be able, flying through a distant star system, to transmit the results of its observations via radio to Earth. Thus, the entire mission will take about 56 years.

Rice. 3. The Stanford Tor is a colossal structure with entire cities inside the rim.

Despite the great difficulties in ensuring the reliability of Daedalus’s numerous systems and its enormous cost, this project can be implemented at the current level of technology. Moreover, in 2009, a team of enthusiasts revived work on the thermonuclear ship project. The Icarus project currently includes 20 scientific topics on the theoretical development of interstellar spacecraft systems and materials.

Thus, unmanned aerial vehicles are already possible today. interstellar flights to a distance of up to 10 light years, which would take about 100 years of flight plus the time it takes for the radio signal to travel back to Earth. This radius fits star systems Alpha Centauri, Barnard's Star, Sirius, Epsilon Eridani, UV Ceti, Ross 154 and 248, CN Leo, WISE 1541–2250. As we can see, there are enough objects near the Earth to be studied using unmanned missions. But what if robots find something truly unusual and unique, such as a complex biosphere? Will an expedition with human participation be able to go to distant planets?

Lifelong flight

If we can start building an unmanned ship today, the situation with a manned one is more complicated. First of all, the issue of flight time is acute. Let's take the same Barnard star. Cosmonauts will have to be prepared for a manned flight from school, since even if the launch from Earth takes place on their 20th anniversary, the spacecraft will reach the mission goal by the 70th or even 100th anniversary (taking into account the need for braking, which is not necessary in an unmanned flight) . Selecting a crew at a young age is fraught with psychological incompatibility and interpersonal conflicts, and the age of 100 years does not give hope for fruitful work on the surface of the planet and for returning home.

However, is there any point in returning? Numerous NASA studies lead to a disappointing conclusion: a prolonged 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 with vigorous exercise on board the spacecraft, large muscles such as the calf muscles will be 50% weaker after a three-year mission to Mars. Bone mineral density also decreases similarly. As a result, ability to work and survival in extreme situations decreases significantly, and the period of adaptation to normal gravity will be at least a year.

Flight 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, during braking with gradually increasing gravity. However, the risk of death is still too high and requires a radical solution.

The problem of radiation also remains difficult. Even near the Earth (on board the ISS), astronauts stay no more than six months due to the danger of radiation exposure. The interplanetary spacecraft will have to be equipped with heavy protection, but the question of the effect of radiation on the human body remains. In particular, at risk oncological diseases, the development of which in zero gravity has been practically not studied. Earlier this year, scientist Krasimir Ivanov from the German Aerospace Center in Cologne published the results interesting research behavior of melanoma cells (the most dangerous form of skin cancer) in zero gravity. Compared to cancer cells grown in normal gravity, cells grown in zero gravity for 6 and 24 hours were less likely to metastasize. This seems to be good news, but only at first glance. The fact is that such “space” cancer can remain dormant for decades, and spread unexpectedly on a large scale when the immune system is disrupted. In addition, the study makes it clear that we still know little about the human body's response to prolonged exposure to space. Today, astronauts, healthy, strong people, spend too little time there to transfer their experience to a long interstellar flight.

Rice. 4. The Biosphere-2 project began with a beautiful, carefully selected and healthy ecosystem...

Unfortunately, solving the problem of weightlessness on an interstellar ship is not so simple. The ability available to us to create artificial gravity by rotating the residential module has a number of difficulties. To create earthly gravity, even a wheel with a diameter of 200 m would have to be rotated at a speed of 3 revolutions per minute. With such rapid rotation, the Cariolis force will create loads that are completely unbearable for the human vestibular system, causing nausea and acute attacks 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 astronauts could live. Due to its size, it provides a gravity force of 0.9–1.0 g and quite comfortable living conditions for 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.

Rice. 5. ...and ended in an environmental disaster.

In any case, a ship for 10 thousand people is a dubious idea.

To create a reliable ecosystem for so many people, you need a huge number of plants, 60 thousand chickens, 30 thousand rabbits and a herd of cattle. This alone can provide a diet of 2,400 calories per day. However, all experiments to create such closed ecosystems invariably end in failure. Thus, during the largest experiment “Biosphere-2” Space company Biosphere Ventures built a network of hermetic buildings with a total area of ​​1.5 hectares with 3 thousand species of plants and animals. The entire ecosystem was supposed to become a self-sustaining little “planet” inhabited by 8 people.

The experiment lasted 2 years, but after just a few weeks serious problems began: microorganisms and insects began to multiply uncontrollably, consuming oxygen and plants too much. large quantities, it also turned out that without wind the plants became too fragile.

As a result of a local environmental disaster, people began to lose weight, the amount of oxygen decreased from 21% to 15%, and scientists had to violate the conditions of the experiment and supply the eight “cosmonauts” with oxygen and food.

Thus, the creation of complex ecosystems seems to be a misguided and dangerous way to provide oxygen and nutrition to the crew of an interstellar spacecraft. To solve this problem, specially designed organisms with altered genes will be needed that can feed on light, waste and simple substances. For example, large modern workshops for the production of edible algae chlorella 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 satisfy the crew's nutritional needs, but also recycle waste, including carbon dioxide. Today, the process of genetically engineering microalgae has become commonplace, and there are numerous samples designed to purify 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 slowing down of human life processes at least several times. If it is possible to plunge a person into such artificial lethargy, which slows down the metabolism 10 times, then during a 100-year flight he will age in his sleep by only 10 years. This makes it easier to solve problems of nutrition, oxygen supply, mental disorders, destruction of the body as a result of exposure to weightlessness. In addition, it is easier to protect a compartment with suspended animation chambers from micrometeorites and radiation than a large habitable zone.

Unfortunately, the slowing down of human life processes 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 remain alive for decades, even when frozen into a block of ice with a temperature of minus 35–40°C. There are known cases when salamanders spent about 100 years in hibernation and, as if nothing had happened, thawed out and ran away from surprised researchers. Moreover, the usual “continuous” life expectancy of a lizard does not exceed 13 years. Amazing ability 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.

Rice. 6. A bioreactor for growing genetically modified microalgae and other microorganisms can solve the problem of nutrition and waste recycling.

The main obstacle to immersing a person in cryostasis is water, which makes up 70% of our body.

When frozen, it turns into ice crystals, increasing in volume by 10%, which causes the cell membrane to rupture. In addition, as freezing occurs, substances dissolved inside the cell migrate into the remaining water, disrupting intracellular ion exchange processes, as well as the organization proteins and others 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 British scientist Sir Humphry Davy introduced high-pressure chlorine into water and witnessed the formation of solid structures. These were clathrate hydrates - one of the forms of water ice, which contains foreign gas. Unlike ice crystals, clathrate lattices are less solid, do not have sharp edges, but have cavities in which intracellular substances can “hide”. The technology of clathrate anabiosis would be simple: inert gas, for example, xenon or argon, the temperature is just below zero, and cellular metabolism begins to gradually slow down until the 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 has been some success in this area. Thus, clathrates are able to protect cardiac muscle tissue from the destruction of mitochondria even at cryogenic temperatures (below 100 degrees Celsius), as well as prevent damage to cell membranes. There is no talk yet about experiments on clathrate anabiosis in humans, since the commercial demand for cryostasis technologies is small and research on this topic is mainly carried out small companies, offering services for freezing the bodies of the deceased.

Flight on hydrogen

In 1960, physicist Robert Bussard proposed the original concept of a ramjet thermonuclear engine, which solves many of the problems of interstellar travel. The idea is to use 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 “free” fuel, it is possible to move with constant acceleration at 1 g, which means all the problems associated with weightlessness disappear. In addition, the engine allows you to accelerate to enormous speeds - 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 earthly years, and for the crew, due to relativistic effects, only 5 years of ship time would have passed.

Unfortunately, the path to creating a ship with a Bussard engine faces a number of serious problems that cannot be solved at the current level of technology. First of all, it is necessary to create a giant and reliable trap for hydrogen, generating magnetic fields of gigantic strength. At the same time, it must ensure minimal losses and efficient transportation of hydrogen to the thermonuclear reactor. The very process of the thermonuclear reaction of converting 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 gives hope that the problem can be solved, for example, by using “exotic” isotopes and antimatter as a catalyst for the reaction.

Rice. 7. The Siberian salamander can go into suspended animation for decades.

So far, research on the topic of the Bussard engine lies exclusively in the theoretical plane. Calculations based on real technologies. First of all, it is necessary to develop an engine capable of producing enough energy to power the magnetic trap and maintain the thermonuclear reaction, produce antimatter and overcome the resistance of the interstellar medium, which will slow down the huge electromagnetic “sail”.

Antimatter to the rescue

This may sound strange, but today humanity is closer to creating an antimatter engine than to the intuitive and seemingly simple Bussard ramjet engine.

A deuterium-tritium fusion reactor can generate 6 x 10 11 J per 1 g of hydrogen - looks impressive, especially considering that this is 10 million times more efficient than chemical rockets. The reaction of matter and antimatter produces approximately two orders of magnitude more energy. When it comes to annihilation, the calculations of scientist Mark Millis and the fruit of his 27 years of work do not look so depressing: Millis calculated the energy costs of launching a spacecraft to Alpha Centauri and found that they would be 10 18 J, i.e. almost the annual electricity consumption of all humanity.

But this is only one kilogram of antimatter.

Rice. 8. The probe developed by Hbar Technologies will have a thin sail made of carbon fiber coated with uranium 238. By crashing into the sail, the antihydrogen will annihilate and create jet thrust.

As a result of the annihilation of hydrogen and antihydrogen, a powerful stream of photons is formed, the outflow speed of which reaches a maximum for a rocket engine, i.e. speed of light. This is an ideal indicator that allows achieving very high near-light speeds of a photon-powered spacecraft. Unfortunately, using antimatter as rocket fuel is very difficult, since during annihilation there are bursts of powerful gamma radiation that will kill astronauts. Also, there are no technologies for storing large amounts of antimatter yet, and the very fact of accumulating tons of antimatter, even in space far from Earth, is a serious threat, since the annihilation of even one kilogram of antimatter is equivalent to a nuclear explosion with a power of 43 megatons (an explosion of such force can turn a third into desert US territory). The cost of antimatter is another factor complicating photon-powered interstellar flight. Modern antimatter production technologies 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. Currently, special positron storage facilities 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 2000 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 UC scientists is to create portable antimatter tanks that can be used for scientific purposes far from large accelerators. The project has the support of the Pentagon, which is interested in military applications of antimatter, so the world's largest array of magnetic bottles is unlikely to be short of funding.

Modern accelerators will be able to produce one gram of antihydrogen in several hundred years. This is a very long time, so the only way out is to develop new technology production of antimatter or unite the efforts of all countries on our planet. But even in this case, with modern technologies, it is impossible to even dream of producing tens of tons of antimatter for an 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 approximately $5 billion per gram.

The American company Hbar Technologies, with the support of NASA, is developing the concept of unmanned probes driven by an engine running on antihydrogen. The first goal of this project is to create an unmanned spacecraft that could fly to the Kuiper belt on the outskirts of the solar system in less than 10 years. Today it is impossible to fly to such distant points in 5-7 years; in particular, NASA's New Horizons probe will fly through the Kuiper belt 15 years after launch.

A probe traveling 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 would produce that amount within a few decades, and scientists could test the new engine concept on a real space mission.

Preliminary calculations also show that a small probe could be sent to Alpha Centauri in a similar manner. On one gram of antihydrogen it will reach a distant star in 40 years.

It may seem that all of the above is fantasy and has nothing to do with the near future. Fortunately, this is not the case. While public attention is focused on global crises, failures of pop stars and other current events, epoch-making initiatives remain in the shadows. The NASA space agency has launched the ambitious 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 has no analogues in the history of mankind and should attract scientists, engineers and enthusiasts of other professions from all over the world. A symposium will be held from September 30 to October 2, 2011 in Orlando, Florida, to discuss various technologies space flights. 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 currently missing, but necessary for future interstellar travel. If NASA's ambitious program is successful, within 100 years humanity will be able to build an interstellar spacecraft, and we will move around the solar system with the same ease as we fly from continent to continent today.

The expression “Fly to the Moon” evokes associations on the verge of fantasy for most of us, comparable only to projects like Apollo 11 to deliver a person to the surface of the Moon. The Breakthrough Starshot Initiative is taking us much further than the Moon as it aims to travel to nearby solar systems.

Interstellar travel:

The brainchild of Russian-born billionaire techno-innovator Yuri Milner, Breakthrough Starshot was announced at a press conference in April 2016 with the participation of such famous scientists as Stephen Hawking and Freeman Dyson. The essence of the technology is as follows: thousands of plate-shaped chips attached to a large silver light sail will be placed in Earth orbit. Then this sail will, in literally, will be pushed into deep space by a beam of laser beams directed from the ground.

After just two minutes of targeted laser action, the space sail will reach 1/5 the speed of light - that's 1000 times faster than the speeds ever achieved by macroscopic objects.

During its twenty-year flight, the ship will collect data about interstellar space. Upon reaching the constellation Alpha Centauri the onboard camera will take a series of high-precision images and send them to Earth. This will give us the opportunity to look at our closest planetary neighbors and understand how suitable they may be for colonization.

The team behind Breakthrough Starshot is as impressive as the idea itself. The board of directors included Milner, Hawking and Mark Zuckerberg. Executive Director appointed former head of the NASA Ames Research Center - Pete Worden (S. Pete Worden). Other participants include Nobel laureates and other advisors to the Breakthrough project. Milner promises to invest his own 100 million dollars to start the project and over the next few years to raise another 10 billion with the help of his colleagues.

At first glance, this may seem like science fiction, although in fact there are no scientific obstacles to the implementation of this project. This doesn't mean everything will happen tomorrow. For a successful Breakthrough to the Stars, it is necessary to make a number of scientific discoveries. Project participants and consultants expect exponential growth in technology that will make Breakthrough Starshot possible over the next 20 years.

Exoplanet detection

Exoplanets include all planets outside our solar system. While the first discoveries date back to 1988, as of May 1, 2017, 3,608 exoplanets have been discovered in 2,702 solar systems. Some of the planets are very similar to ours, others have a number of unique features, such as rings 200 times wider than those of our Saturn.

The reason for this explosion of finds is a powerful breakthrough in improving telescopic technologies.

Just 100 years ago the most large telescope in the world there was a Hooker Telescope with a lens with a diameter of 2.5 meters. Today, the European Southern Observatory has a complex of four telescopes, each 8.2 meters in diameter. It is considered the largest ground-based structure for the study of astronomy, publishing on average one peer-reviewed scientific document per day.

Scientists also use MBT () and special tools to search for rocky planets in the “habitable” (allowing liquid water) zones of other solar systems. In May 2016, using TRAPPIST (Transiting Planets and Planetesimals Small Telescope), researchers in Chile discovered seven Earth-sized exoplanets in the habitable zone.

Meanwhile, the NASA Kepler spacecraft, created specifically for these purposes, has already identified more than 2,000 exoplanets. The James Webb Space Telescope (JWST), scheduled to launch in October 2018, will open up never-before-seen opportunities to test exoplanets for the presence of life. "If these planets have atmospheres, the Webb telescope will be the key to unlocking their secrets," says Doug Hudgins, a scientist with NASA's exoplanet program at its headquarters in Washington.

Launch cost

The Starshot mothership will be lifted off the ground by a launch vehicle and then release a thousand small plates into space. The cost of launching payloads with disposable rockets is too high, but companies such as SpaceX and Blue Origin are showing real hope in using reusable rockets that will significantly reduce launch costs. SpaceX has already been able to reduce Falcon 9 launch costs by $60 million. With an increase in the share of private space companies on the world market, launching reusable rockets will become more accessible and cheaper.

Star plate

Each 15mm wafer will have to accommodate a variety of complex electronic devices, such as a navigator, a camera, a communications laser, a radioisotope battery, a multiplex camera and an interface camera. The possibility of packing an entire spacecraft onto a tiny plate is explained by the exponential reduction in the size of sensors and chips.

In the 1960s the first computer chips consisted of a whole handful of transistors. Today, thanks to Moore's Law, we can fit billions of transistors onto a single chip. The first digital camera weighed 8 pounds and shot 0.01 megapixels. Now digital cameras that take high-quality 12-megapixel color images fit into a smartphone with a bunch of other sensors like GPS, accelerometer and gyroscope. With the advent of smaller satellites providing better data, we are seeing all of these improvements being applied to space exploration.

For Starshot to be successful, we will need the chip to weigh about 0.22 grams by 2030. If the pace of improvement continues, projections suggest this is entirely possible.

Light sail

The sail must be made of a material that is highly reflective (to get maximum acceleration from the laser), minimally absorbent (so it doesn't burn from heat), and also very light in weight (allowing rapid acceleration). This is an extremely complex combination and is currently suitable material not found yet.

Application of automation artificial intelligence will speed up the discovery of such materials. The essence of automation is that the machine will be able to generate a library of tens of thousands of materials for testing. This will make the selection task much easier for engineers. best options for research and development.

Battery

Although Starchip will use a tiny nuclear radioisotope battery for the 24-year journey, we will still need conventional chemical batteries for the lasers. Lasers will expend enormous amounts of energy in a short period of time, which means the power must be kept as close as possible.

Battery capacity is growing by an average of 5-8% per year; We often don’t notice this because the energy consumption of gadgets increases proportionally, leaving the overall service life the same. If the dynamics of battery improvement continue, in 20 years they should have an increase of 3-5 times their current capacity. These expectations rely on Tesla-Solar City's innovation from investments in battery technology. Companies in Kauai have already installed about 55,000 batteries to power much of their infrastructure.

Lasers

Thousands of powerful lasers will be used to accelerate the sail to light speeds.

Laser technology followed Moore's Law at the same rate as integrated circuits, cutting its cost-to-power ratio in half every 18 months. The last decade in particular has seen a surge in power scaling for diode and fiber lasers, with the former being able to squeeze 10 kilowatts out of single-mode fiber in 2010 and 100 kilowatts months later. Along with conventional power, we also need to improve phased array laser fusion technologies.

Speed

Our ability to move quickly, moved quickly... In 1804, the first steam locomotive was invented, reaching an unprecedented speed of 110 km/h. The Helios 2 spacecraft broke this record in 1976, moving away from Earth at a speed of 356,040 km/h. 40 years later, the New Horizons spacecraft reached a heliocentric speed of almost 45 km/s or 160,000 km/h. But even with these speeds, it will take a very long time to get to Alpha Centauri, more than four light years away.

While accelerating subatomic particles to the speed of light is common in particle accelerators, this has never before been achieved by macroscopic objects. Achieving just 20% the speed of light for Starshot would represent a 1000-fold increase in speed for anything ever built by man.

Data storage

Basis for computer technology is the ability to store information. Starshot relies on continuing to reduce the cost and size of digital memory to ensure there is sufficient capacity to store its programs and images captured in the Alpha Centauri system and its planets.

The cost of memory has been falling exponentially for decades: in 1970, a megabyte cost about a million dollars; Now about 0.1 cent. Storage sizes have also shrunk, from a 5-megabyte hard drive loaded with a forklift in 1956 to the now-available 512-gigabyte USB flash drives weighing a few grams.

Connection

Once the first images are received, Starchip will send them to Earth for processing.

Since Alexander Graham Bell invented the telephone in 1876, telecommunications have come a long way. average speed Internet speed in the US today is about 11 megabits per second. Channel width and speed required by Starshot to send digital images at a distance of four light years (or 20 trillion miles), will require the use the latest developments in the field of communications.

One promising technology is Li-Fi, a wireless connection 100 times faster than Wi-Fi. The second is optical fibers, which now allow transmission of 1.125 terabits per second. In addition to these, there are developments in the field of quantum communications, which are not only ultra-fast, but also absolutely safe.

Data processing

The final step in the Starshot project is to analyze the data received from the spacecraft. The bet is on an exponential increase in computing power with a trillion-fold increase over the next 60 years.

The rapid reduction in the cost of this moment is largely associated with the development of cloud computing. Looking to the future, quantum information processing methods promise a thousandfold increase in power by the time the first data is received from Starshot. Such advanced processors will make it possible to perform complex scientific simulations and analyzes of nearby star systems.

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In our Galaxy alone, the distances between star systems are unimaginably vast. If aliens from outer space really visit Earth, the level of their technical development should be a hundred times higher than the current level of ours on earth.

Several light years away

To indicate the distances between stars, astronomers introduced the concept of “light year”. The speed of light is the fastest in the Universe: 300,000 km/s!

The width of our Galaxy is 100,000 light years. To cover such a huge distance, aliens from other planets need to build spaceship, the speed of which is equal to or even exceeds the speed of light.

Scientists believe that a material object cannot move faster than the speed of light. However, they previously believed that it was impossible to develop supersonic speed, but in 1947, the Bell X-1 model aircraft successfully broke the sound barrier.

Perhaps in the future, when humanity has accumulated more knowledge about the physical laws of the Universe, earthlings will be able to build a spaceship that will move at the speed of light and even faster.

Great Journeys

Even if aliens are capable of traveling through space at the speed of light, such a journey would take many years. For earthlings, whose life expectancy is on average 80 years, this would be impossible. However, each species of living beings has its own life cycle. For example, in California, USA, there are bristlecone pines that are already 5000 years old.

Who knows how many years aliens live? Maybe several thousand? Then interstellar flights lasting hundreds of years are common for them.

Shortest paths

It is likely that aliens found shortcuts through space- gravitational “holes”, or distortions of space formed by gravity. Such places in the Universe could become a kind of bridges - the shortest paths between celestial bodies located at different ends of the Universe.

If you use existing technologies, it will take a very, very long time to send scientists and astronauts on an interstellar mission. The journey will be painfully long (even by cosmic standards). If we want to accomplish such a journey in at least one lifetime, or even a generation, we need more radical (read: purely theoretical) measures. And while wormholes and subspace engines are absolutely fantastic at the moment, there have been other ideas for many years that we believe in being realized.

Nuclear propulsion

Nuclear power point is a theoretically possible “engine” for fast space travel. The concept was originally proposed by Stanislaw Ulam in 1946, a Polish-American mathematician who took part in the Manhattan Project, and preliminary calculations were made by F. Reines and Ulam in 1947. Project Orion was launched in 1958 and lasted until 1963.

Led by Ted Taylor of General Atomics and physicist Freeman Dyson of the Institute for Advanced Study at Princeton, Orion would harness the power of pulsed nuclear explosions to provide enormous thrust with very high specific impulse.

In a nutshell, Project Orion involves a large spacecraft that gains speed by supporting thermonuclear warheads, ejecting bombs behind and accelerating through a blast wave that goes into a rear-mounted “pusher,” a propulsion panel. After each push, the force of the explosion is absorbed by this panel and converted into forward movement.

Although this design is hardly elegant by modern standards, the advantage of the concept is that it provides high specific thrust - that is, it extracts the maximum amount of energy from the fuel source (in this case nuclear bombs) at minimal cost. In addition, this concept can theoretically overclock very high speeds, according to some estimates, up to 5% of the speed of light (5.4 x 10 7 km/h).

Of course, this project has inevitable disadvantages. On the one hand, a ship of this size will be extremely expensive to build. Dyson estimated in 1968 that the Orion spacecraft, powered by hydrogen bombs, would have weighed between 400,000 and 4,000,000 metric tons. And at least three quarters of this weight will come from nuclear bombs, each of which weighs approximately one ton.

Dyson's conservative calculations showed that the total cost of building Orion would be $367 billion. Adjusted for inflation, this amount comes out to $2.5 trillion, which is quite a lot. Even with the most conservative estimates, the device will be extremely expensive to produce.

There's also the small issue of the radiation it will emit, not to mention the nuclear waste. It is believed that this is why the project was scrapped as part of the partial test ban treaty of 1963, when world governments sought to limit nuclear testing and stop the excessive release of radioactive fallout into the planet's atmosphere.

Fusion rockets

Another possible use nuclear energy consists of thermonuclear reactions to produce thrust. In this concept, energy would be created by igniting pellets of a mixture of deuterium and helium-3 in a reaction chamber by inertial confinement using electron beams (similar to what is done at the National Ignition Facility in California). Such a fusion reactor would explode 250 pellets per second, creating a high-energy plasma that would then be redirected into a nozzle, creating thrust.

Like a rocket that relies on a nuclear reactor, this concept has advantages in terms of fuel efficiency and specific impulse. The speed is estimated to reach 10,600 km/h, far exceeding the speed limits of conventional rockets. Moreover, this technology has been extensively studied over the past few decades and many proposals have been made.

For example, between 1973 and 1978, the British Interplanetary Society conducted a study into the feasibility of Project Daedalus. Drawing on modern knowledge and fusion technology, scientists have called for the construction of a two-stage unmanned scientific probe that could reach Barnard's Star (5.9 light-years from Earth) within a human lifetime.

The first stage, the largest of the two, would operate for 2.05 years and accelerate the craft to 7.1% the speed of light. Then this stage is discarded, the second one is ignited, and the device accelerates to 12% of the speed of light in 1.8 years. Then the second stage engine is turned off, and the ship flies for 46 years.

Project Daedalus estimates that the mission would have taken 50 years to reach Barnard's Star. If to Proxima Centauri, the same ship will get there in 36 years. But, of course, the project includes a lot of unresolved issues, in particular those that cannot be resolved using modern technologies - and most of them have not yet been resolved.

For example, there is practically no helium-3 on Earth, which means it will have to be mined elsewhere (most likely on the Moon). Second, the reaction that drives the apparatus requires that the energy emitted significantly exceeds the energy expended to start the reaction. And although experiments on Earth have already surpassed the “break-even point,” we are still far from the volumes of energy that can power an interstellar spacecraft.

Thirdly, the question of the cost of such a vessel remains. Even by the modest standards of the Project Daedalus unmanned vehicle, a fully equipped vehicle would weigh 60,000 tons. To give you an idea, the gross weight of NASA SLS is just over 30 metric tons, and the launch alone will cost $5 billion (2013 estimates).

In short, not only would a fusion rocket be too expensive to build, but it would also require a level fusion reactor, far beyond our capabilities. Icarus Interstellar, an international organization of citizen scientists (some of whom worked for NASA or ESA), is trying to revive the concept with Project Icarus. Formed in 2009, the group hopes to make the fusion movement (and more) possible for the foreseeable future.

Fusion ramjet

Also known as the Bussard ramjet, the engine was first proposed by physicist Robert Bussard in 1960. At its core, it is an improvement on the standard fusion rocket, which uses magnetic fields to compress hydrogen fuel to the fusion point. But in the case of a ramjet, a huge electromagnetic funnel sucks hydrogen from the interstellar medium and dumps it into the reactor as fuel.

As the vehicle gains speed, the reactive mass enters a confining magnetic field, which compresses it until thermonuclear fusion begins. The magnetic field then directs energy into the rocket nozzle, accelerating the craft. Since no fuel tanks will slow it down, a fusion ramjet can reach speeds on the order of 4% of light speed and travel anywhere in the galaxy.

However, there are many potential downsides to this mission. For example, the problem of friction. The spacecraft relies on a high rate of fuel collection, but will also encounter large amounts of interstellar hydrogen and lose speed - especially in dense regions of the galaxy. Secondly, there is little deuterium and tritium (which are used in reactors on Earth) in space, and the synthesis of ordinary hydrogen, which is abundant in space, is not yet within our control.

However, science fiction fell in love with this concept. The most famous example is perhaps the Star Trek franchise, which uses Bussard collectors. In reality, our understanding of fusion reactors is not nearly as good as we would like.

Laser sail

Solar sails have long been considered an effective way to conquer the solar system. Besides the fact that they are relatively simple and cheap to manufacture, they have the big advantage that they do not require fuel. Instead of using rockets that need fuel, the sail uses radiation pressure from stars to propel ultra-thin mirrors to high speeds.

However, in the case of interstellar travel, such a sail would have to be propelled by focused beams of energy (laser or microwaves) to accelerate it to near light speed. The concept was first proposed by Robert Forward in 1984, a physicist at Hughes Aircraft Laboratory.

His idea retains the advantages of a solar sail in that it does not require fuel on board, and also that laser energy does not dissipate over a distance in the same way as solar radiation. Thus, although the laser sail will take some time to accelerate to near light speed, it will subsequently be limited only by the speed of light itself.

According to a 2000 study by Robert Frisby, director of advanced propulsion concepts research at NASA's Jet Propulsion Laboratory, a laser sail would accelerate to half the speed of light in less than a decade. He also calculated that a sail with a diameter of 320 kilometers could reach Proxima Centauri in 12 years. Meanwhile, the sail, 965 kilometers in diameter, will arrive in just 9 years.

However, such a sail will have to be built from advanced composite materials to avoid melting. Which will be especially difficult given the size of the sail. Costs are even worse. According to Frisbee, the lasers would require a steady flow of 17,000 terawatts of energy, which is roughly what the entire world consumes in one day.

Antimatter engine

Science fiction fans are well aware of what antimatter is. But in case you forgot, antimatter is a substance made up of particles that have the same mass as regular particles but the opposite charge. An antimatter engine is a hypothetical engine that relies on interactions between matter and antimatter to generate energy, or thrust.

In short, an antimatter engine uses hydrogen and antihydrogen particles colliding together. The energy emitted during the annihilation process is comparable in volume to the energy of the explosion of a thermonuclear bomb accompanied by a flow of subatomic particles - pions and muons. These particles, which travel at one-third the speed of light, are redirected into a magnetic nozzle and generate thrust.

The advantage of this class of rocket is that most of the mass of the matter/antimatter mixture can be converted into energy, resulting in a high energy density and specific impulse superior to any other rocket. Moreover, the annihilation reaction can accelerate the rocket to half the speed of light.

This class of rockets will be the fastest and most energy efficient possible (or impossible, but proposed). While conventional chemical rockets require tons of fuel to propel a spacecraft to its destination, an antimatter engine will do the same job with just a few milligrams of fuel. The mutual destruction of half a kilogram of hydrogen and antihydrogen particles releases more energy than a 10-megaton hydrogen bomb.

It is for this reason that NASA's Advanced Concepts Institute is researching this technology as a possibility for future missions to Mars. Unfortunately, when considering missions to nearby star systems, the amount of fuel required increases by geometric progression, and the costs become astronomical (no pun intended).

According to a report prepared for the 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, a two-stage antimatter rocket would require more than 815,000 metric tons of propellant to reach Proxima Centauri in 40 years. It's relatively fast. But the price...

Although one gram of antimatter produces an incredible amount of energy, producing just one gram would require 25 million billion kilowatt-hours of energy and cost a trillion dollars. Currently total of antimatter that was created by humans is less than 20 nanograms.

And even if we could produce antimatter cheaply, we would need a massive ship that could hold the required amount of fuel. According to a report by Dr. Darrell Smith and Jonathan Webby of Embry-Riddle Aeronautical University in Arizona, an antimatter-powered interstellar spacecraft could reach the speed of 0.5 times the speed of light and reach Proxima Centauri in just over 8 years. However, the ship itself would weigh 400 tons and require 170 tons of antimatter fuel.

A possible way around this would be to create a vessel that would create antimatter and then use it as fuel. This concept, known as the Vacuum to Antimatter Rocket Interstellar Explorer System (VARIES), was proposed by Richard Aubauzi of Icarus Interstellar. Based on the idea of ​​in-situ recycling, the VARIES vehicle would use large lasers (powered by huge solar panels) to create antimatter particles when fired into empty space.

Similar to the fusion ramjet concept, this proposal solves the problem of transporting fuel by extracting it directly from space. But again, the cost of such a ship will be extremely high if it is built by our modern methods. We simply cannot create antimatter on a huge scale. There is also a radiation problem to be solved, since the annihilation of matter and antimatter produces bursts of high-energy gamma rays.

They not only pose a danger to the crew, but also to the engine, so that they do not fall apart. subatomic particles under the influence of all this radiation. In short, an antimatter engine is completely impractical given our current technology.

Alcubierre Warp Drive

Science fiction fans are no doubt familiar with the concept of warp drive (or Alcubierre drive). Proposed by Mexican physicist Miguel Alcubierre in 1994, the idea was an attempt to imagine instantaneous movement in space without violating Einstein's theory of special relativity. In short, this concept involves stretching the fabric of spacetime into a wave, which would theoretically cause the space in front of an object to contract and the space behind it to expand.

An object inside this wave (our ship) will be able to ride this wave, being in a “warp bubble,” at a speed much higher than the relativistic one. Since the ship does not move in the bubble itself, but is carried by it, the laws of relativity and space-time will not be violated. Essentially, this method does not involve moving faster than the speed of light in a local sense.

It is "faster than light" only in the sense that the ship can reach its destination faster than a beam of light traveling outside the warp bubble. Assuming the spacecraft is equipped with the Alcubierre system, it will reach Proxima Centauri in less than 4 years. Therefore, when it comes to theoretical interstellar space travel, this is by far the most promising technology in terms of speed.

Of course, this whole concept is extremely controversial. Among the arguments against, for example, is that it does not take quantum mechanics into account and can be refuted by a theory of everything (like the loop theory quantum gravity). Calculations of the required amount of energy also showed that the warp drive would be prohibitively voracious. Other uncertainties include the safety of such a system, spacetime effects at the destination, and violations of causality.

However, in 2012, NASA scientist Harold White announced that he and his colleagues began exploring the possibility of creating an Alcubierre engine. White stated that they had built an interferometer that would capture the spatial distortions produced by the expansion and contraction of spacetime in the Alcubierre metric.

In 2013, the Jet Propulsion Laboratory published the results of warp field tests conducted in vacuum conditions. Unfortunately, the results were considered “inconclusive.” In the long term, we may find that the Alcubierre metric violates one or more fundamental laws of nature. And even if its physics prove correct, there is no guarantee that the Alcubierre system can be used for flight.

In general, everything is as usual: you were born too early to travel to the nearest star. However, if humanity feels the need to build an "interstellar ark" that will contain a self-sustaining human society, it will take about a hundred years to get to Proxima Centauri. If, of course, we want to invest in such an event.

In terms of time, all available methods seem to be extremely limited. And while spending hundreds of thousands of years traveling to the nearest star may be of little interest to us when our own survival is at stake, as space technology advances, the methods will remain extremely impractical. By the time our ark reaches the nearest star, its technology will become obsolete, and humanity itself may no longer exist.

So unless we make a major breakthrough in fusion, antimatter, or laser technology, we will be content with exploring our own solar system.