11.06.2010 00:10
The American spacecraft Dawn recently set a new speed record of 25.5 thousand km/h, ahead of its main competitor, the Deep Space 1 probe. This achievement was made possible thanks to the ultra-powerful ion engine installed on the device. However, according to experts NASA, this is far from the limit of its capabilities.
The speed of the American spacecraft Dawn reached a record value on June 5 - 25.5 thousand km/h. However, according to scientists, in the near future the ship’s speed will reach 100 thousand km/h.
Thus, thanks to its unique engine, Dawn surpassed its predecessor, the Deep Space 1 probe, an experimental automatic spacecraft launched on October 24, 1998 by a launch vehicle. True, Deep Space 1 still retains the title of the station whose engines lasted the longest. But Dawn can get ahead of its “competitor” in this category as early as August.
The main task of the spacecraft, launched three years ago, is to study the asteroid 4 Vesta, which the device will approach in 2011, and the dwarf planet Ceres. Scientists hope to obtain the most accurate data on the shape, size, mass, mineral and elemental composition of these objects located between the orbits of Jupiter and Mars. The total distance to be covered by the Dawn spacecraft is 4 billion 800 million kilometers.
Since there is no air in outer space, having accelerated, the ship continues to move at the same speed. On Earth this is impossible due to slowdown due to friction. The use of ion engines in airless space allowed scientists to make the process of gradually increasing the speed of the Dawn spacecraft as efficient as possible.
The operating principle of the innovative engine is the ionization of gas and its acceleration by an electrostatic field. At the same time, due to the high charge-to-mass ratio, it becomes possible to accelerate the ions to very high speeds. Thus, a very high specific impulse can be achieved in the engine, which can significantly reduce the consumption of the reactive mass of ionized gas (compared to a chemical reaction), but requires large amounts of energy.
Dawn's three engines do not operate constantly, but are turned on briefly at certain points in the flight. To date, they have worked for a total of 620 days and have consumed over 165 kilograms of xenon. Simple calculations show that the speed of the probe increased by about 100 km/h every four days. By the end of Dawn's eight-year mission (although experts do not rule out its extension), the total operating time of the engines will be 2,000 days—almost 5.5 years. Such indicators promise that the speed of the spacecraft will reach 38.6 thousand km/h.
This may seem like a small amount against the background of at least the first cosmic speed with which artificial Earth satellites are launched, but for an interplanetary vehicle without any external accelerators, which does not perform special maneuvers in the gravitational field of the planets, this result is truly remarkable.
Space exploration has long become quite commonplace for humanity. But flights to low-Earth orbit and to other stars are unthinkable without devices that allow one to overcome gravity - rockets. How many of us know: how a launch vehicle works and functions, where the launch takes place and what its speed is, which allows it to overcome the gravity of the planet and 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 describing the nodes from the top to the bottom.
CAC
The device that launches a satellite or cargo compartment into orbit is always distinguished from the carrier, which is intended to transport the crew, by its configuration. The latter has a special emergency rescue system at the very top, which serves to evacuate the compartment from the astronauts in the event of a launch vehicle failure. This non-standard turret, located at the very top, is a miniature rocket that allows you to “pull” a capsule with people up under extraordinary circumstances and move it to a safe distance from the point of the accident. This is important in the initial stage of the flight, where it is still possible to carry out a parachute descent of the capsule In airless space, the role of the SAS becomes less important.In near-Earth space, the astronauts will be saved by a function that makes it possible to separate the descent vehicle from the launch vehicle.
Cargo compartment
Below the SAS there is a compartment carrying a payload: a manned vehicle, a satellite, a cargo compartment. Based on the type and class of the launch vehicle, the mass of the cargo launched into orbit can range from 1.95 to 22.4 tons. All cargo transported by the ship is protected by the head fairing, which is discarded after passing through the atmospheric layers.
Main engine
People far from space think that if a rocket ends up in airless space, at an altitude of one hundred kilometers, where weightlessness begins, then its mission is over. In fact, depending on the task, the target orbit of the cargo launched into space may be much further away. For example, telecommunications satellites must be transported into orbit at an altitude of more than 35 thousand kilometers. To achieve the required removal, a propulsion engine is needed, or as it is otherwise called, an upper stage. To reach the planned interplanetary or departure trajectory, the flight speed mode must be changed more than once, carrying out certain actions, so this engine must be started and turned off repeatedly, this is its difference from other similar rocket components.
Multi-stage
In a launch vehicle, only a small fraction of its mass is occupied by the transported payload; the rest is the engines and fuel tanks, which are located in different stages of the vehicle. A design feature of these units is the possibility of their separation after fuel exhaustion. After which they burn up in the atmosphere without reaching the ground. True, as the news portal reactor.space states, in recent years a technology has been developed that makes it possible to return the separated stages unharmed to a designated point and launch them again into space. In rocket science, when creating multi-stage ships, two schemes are used:
- The first is longitudinal, allowing you to place several identical engines with fuel around the body, which are simultaneously turned on and synchronously reset after use.
- The second is transverse, making it possible to arrange the steps in increasing order, one higher than the other. In this case, they are turned on only after the lower, spent stage is reset.
But often designers give preference to a combination of transverse and longitudinal design. 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, stage fuel tanks consist of reservoirs in which different components are pumped: oxidizer (liquid oxygen, nitrogen tetroxide) and fuel (liquid hydrogen, heptyl). Only with their interaction can the rocket be accelerated to the required speed.
How fast does a rocket fly in space?
Depending on the tasks that the launch vehicle must perform, its speed may vary, being divided into four values:
- The first space one. It allows you to ascend into orbit where it becomes a satellite of the Earth. If we translate into conventional values, it is equal to 8 km/s.
- The second space one. Speed 11.2 km/s. makes it possible for the ship to overcome gravity to explore the planets of our solar system.
- The third is cosmic. Sticking to a speed of 16,650 km/s. you can overcome the gravity of the solar system and leave its limits.
- The fourth space one. Having developed a speed of 550 km/s. the rocket is capable of flying beyond the galaxy.
But no matter how high the speeds of spacecraft are, they are too low 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?
To successfully conquer space, special launch pads are needed from where rockets can be launched into outer space. In everyday use they are called cosmodromes. But this simple name includes a whole complex of buildings occupying vast territories: the launch pad, rooms for final testing and assembly of the rocket, buildings for related services. All this is located at a distance from each other, so that in the event of an accident other structures of the cosmodrome would not be damaged.
Conclusion
The more space technology improves, the more complex the structure and operation of a rocket becomes. Maybe in a few years, new devices will be created to overcome the Earth's gravity. And the next article will be devoted to the operating principles of a more advanced rocket.
One of humanity's greatest assets is the International Space Station, or ISS. Several states united to create it and operate it in orbit: Russia, some European countries, Canada, Japan and the USA. This apparatus shows that much can be achieved if countries constantly cooperate. Everyone on the planet knows about this station and many people ask questions about 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 humanity.
Station structure
The ISS consists of fourteen modules, which house laboratories, warehouses, rest rooms, bedrooms, and utility rooms. The station even has a gym with exercise equipment. This entire complex runs on solar panels. They are huge, the size of a stadium.
Facts about the ISS
During its operation, the station aroused a lot of admiration. This apparatus is the greatest achievement of human minds. In its design, purpose and features, it can be called perfection. Of course, maybe in 100 years they will start building spaceships of a different type on Earth, but for now, today, this device is the property of humanity. This is evidenced by the following facts about the ISS:
- During its existence, about two hundred astronauts visited the ISS. There were also tourists here who simply came to look at the Universe from orbital heights.
- The station is visible from Earth with the naked eye. This structure is the largest among artificial satellites and can be easily seen from the surface of the planet without any magnifying device. There are maps on which you can see what time and when the device flies over cities. Using them you can easily find information about your locality: see the flight schedule over the region.
- To assemble the station and maintain it in working order, the astronauts went into outer space more than 150 times, spending about a thousand hours there.
- The device is controlled by six astronauts. The life support system ensures the continuous presence of people at the station from the moment it was first launched.
- The International Space Station is a unique place where a wide variety of laboratory experiments are conducted. Scientists make unique discoveries in the fields of medicine, biology, chemistry and physics, physiology and meteorological observations, as well as in other fields of science.
- The device uses giant solar panels the size of a football field with its end zones. Their weight is almost three hundred thousand kilograms.
- The batteries are capable of fully ensuring the operation of the station. Their work is carefully 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 cosmonauts:
- Anton Shkaplerov - commander of ISS-55. He visited the station twice - in 2011-2012 and in 2014-2015. During 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 - flight engineer, Japanese astronaut.
- Alexander Misurkin. Its first flight was made in 2013, lasting 166 days.
- Macr Vande Hai 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
There are unique views of Earth from space. This is evidenced by photographs and videos of astronauts and cosmonauts. You can see the work of the station and space landscapes if you watch online broadcasts from the ISS station. However, some cameras are turned off due to maintenance work.
Our reader Nikita Ageev asks: what is the main problem of interstellar travel? The answer, like , will require a long article, although the question can be answered with a single symbol: c .
The speed of light in a vacuum, c, is approximately three hundred thousand kilometers per second, and it is impossible to exceed it. Therefore, it is impossible to reach the stars faster than in a few years (light travels 4.243 years to Proxima Centauri, so the spacecraft cannot arrive even faster). If you add the time for acceleration and deceleration with acceleration more or less acceptable for humans, you get about ten years to the nearest star.
What are the conditions to fly in?
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 - the astronauts are constantly brought fresh supplies from Earth. Usually, conversations about the problems of interstellar travel begin with more fundamental questions, but we will start with purely applied problems.
Even half a century after Gagarin’s flight, engineers were unable to create a washing machine and a sufficiently 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 for a trip to the stars it will be necessary to at least invent a space toilet with a twenty-year guarantee and the same washing machine.
Water for washing, washing and drinking will also have to be either taken with you or reused. As well as air, and food also needs to be either stored or grown on board. Experiments to create a closed ecosystem on Earth have already been carried out, but their conditions were still very different from space ones, at least in the presence of gravity. Humanity knows how to turn the contents of a chamber pot into clean drinking water, but in this case it is necessary to be able to do this in zero gravity, with absolute reliability and without a truckload of consumables: 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 - however, any experienced traveler will confirm that “little things” like uncomfortable shoes or stomach upset from unfamiliar food on an autonomous expedition can turn into a threat to life.
Solving even basic everyday problems requires just as serious a technological base as the development of fundamentally new space engines. If on Earth a worn-out gasket in a toilet cistern can be bought at the nearest store for two rubles, then on the Martian ship it is necessary to provide either a reserve everyone 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 started 3D printing after we assessed the time and money spent on repairing military equipment using traditional methods in the field. The military reasoned that printing some rare gasket for a helicopter component that had been discontinued ten years ago was easier than ordering a part from a warehouse on another continent.
One of Korolev’s closest associates, Boris Chertok, wrote in his memoirs “Rockets and People” that at a certain point the Soviet space program was faced with a shortage of plug contacts. Reliable connectors for multi-core cables had to be developed separately.
In addition to spare parts for equipment, food, water and air, astronauts will need energy. The engine and on-board equipment will need energy, so the problem of a powerful and reliable source will have to be solved separately. Solar batteries are not suitable, if only because of the distance from the stars in flight, radioisotope generators (they power Voyagers and New Horizons) do not provide the power required for a large manned spacecraft, and they have not yet learned how to make full-fledged nuclear reactors for space.
The Soviet nuclear-powered satellite program was marred by an international scandal following the crash of Cosmos 954 in Canada, as well as a series of less dramatic failures; similar work in the United States was stopped even earlier. Now Rosatom and Roscosmos intend to create a space nuclear power plant, but these are still installations for short-range flights, and not a multi-year journey to another star system.
Perhaps instead of a nuclear reactor, future interstellar spacecraft will use tokamaks. About how difficult it is to at least correctly determine the parameters of thermonuclear plasma, at MIPT 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?
Conventional rocket engines are not suitable for accelerating and decelerating an interstellar ship. Those familiar with the mechanics course taught at MIPT 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 turns out to be significantly higher than the mass of the Solar system.
The fuel supply can be reduced by increasing the speed at which the engine emits the working fluid, gas, plasma or something else, up to a beam of elementary particles. Currently, plasma and ion engines are actively used for flights of automatic interplanetary stations within the Solar System or for correction of the orbit of geostationary satellites, but they have a number of other disadvantages. In particular, all such engines provide too little thrust; they cannot yet 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. SPD series engines are produced at the Fakel Design Bureau; these are serial products for orbit correction of communication satellites.
In the 1950s, an engine project was developed that would use the impulse of a nuclear explosion (the Orion project), but it was far from becoming a ready-made solution for interstellar flights. Even less developed is the design of an engine that uses the magnetohydrodynamic effect, that is, accelerates due to interaction with interstellar plasma. Theoretically, a spacecraft could “suck” plasma inside and throw it back out to create jet thrust, but this poses another problem.
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 of megaelectronvolts or even tens of megaelectronvolts - the same amount as the products of nuclear reactions. The density of the interstellar medium is about one hundred thousand ions per cubic meter, which means that per second a square meter of the ship's hull will receive about 10 13 protons with energies of tens of MeV.
One electronvolt, 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 this energy, and ultraviolet quanta with higher energy are already capable of damaging DNA molecules. Radiation or particles with energies of megaelectronvolts accompanies nuclear reactions and, in addition, is itself capable of causing them.
Such irradiation corresponds to an absorbed energy (assuming that all energy is absorbed by the skin) of tens of joules. Moreover, this energy will not just come in the form of heat, but may partially be used to initiate nuclear reactions in the ship’s material with the formation of short-lived isotopes: in other words, the lining will become radioactive.
Some of the incident protons and helium nuclei can be deflected aside by a magnetic field; induced radiation and secondary radiation can be protected by a complex shell of many layers, but these problems also have no solution yet. In addition, fundamental difficulties of the form “which material will be least destroyed when irradiated” at the stage of servicing the ship in flight will turn into particular problems - “how to unscrew four 25 bolts in a compartment with a background of fifty millisieverts per hour.”
Let us recall that during the last repair of the Hubble telescope, the astronauts initially failed to unscrew the four bolts that secured one of the cameras. After consulting with the Earth, they replaced the torque-limiting key with a regular one and applied brute force. The bolts moved out of place, the camera was successfully replaced. If the stuck bolt had been removed, the second expedition would have cost half a billion US dollars. Or it wouldn’t have happened at all.
Are there any 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 do you need a lot of energy, 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 unresolved problems in physics is the absence of gravity in the so-called Standard Model, a theory that describes the behavior of elementary particles and three of the four fundamental physical interactions. The vast majority of physicists are quite skeptical that in the quantum theory of gravity there will be a place for interstellar “jumps through hyperspace”, but, strictly speaking, no one forbids trying to look for a workaround for flights to the stars.
However, in space everything is different, some phenomena are simply inexplicable and cannot be subject to any laws in principle. For example, a satellite launched several years ago, or other objects will rotate in their orbit and will never fall. Why is this happening, At what speed does a rocket fly into space?? Physicists suggest that there is a centrifugal force that neutralizes the effect of gravity.
Having done a small experiment, we can understand and feel this ourselves, without leaving home. To do this, you need to take a thread and tie a small weight to one end, then unwind the thread in a circle. We will feel that the higher the speed, the clearer the trajectory of the load, and the more tension the thread will have; if we weaken the force, the speed of rotation of the object will decrease and the risk that the load will fall increases several times. With this little experience we will begin to develop our topic - speed in space.
It becomes clear that high speed allows any object to overcome the force of gravity. As for space objects, they each have their own speed, it is different. There are four main types of such speed and the smallest of them is the first. It is at this speed that the ship flies into Earth orbit.
In order to fly beyond its limits you need a second speed in space. At the third speed, gravity is completely overcome and you can fly out of the solar system. Fourth rocket speed in space will allow you to leave the galaxy itself, this is approximately 550 km/s. We have always been interested rocket speed in space km h, when entering orbit it is equal to 8 km/s, beyond it - 11 km/s, that is, developing its capabilities to 33,000 km/h. The rocket gradually increases speed, full acceleration begins from an altitude of 35 km. Speedspacewalk is 40,000 km/h.
Speed in space: record
Maximum speed in space- the record, set 46 years ago, still stands, it was achieved by astronauts who took part in the Apollo 10 mission. Having flown around the Moon, they returned back when speed of a spaceship in space was 39,897 km/h. In the near future, it is planned to send the Orion spacecraft into zero-gravity space, which will launch astronauts into low Earth orbit. Perhaps then it will be possible to break the 46-year-old record. Speed of light in space- 1 billion km/h. I wonder if we can cover such a distance with our maximum available speed of 40,000 km/h. Here what is the speed in space develops in the light, but we don’t feel it here.
Theoretically, a person can move at a speed slightly less than the speed of light. However, this will entail colossal harm, especially for an unprepared organism. After all, first you need to develop such a speed, make an effort to safely reduce it. Because rapid acceleration and deceleration can be fatal to a person.
In ancient times, it was believed that the Earth was motionless; no one was interested in the question of the speed of its rotation in orbit, because such concepts did not exist in principle. But even now it is difficult to give an unambiguous answer to the question, because the value is not the same in different geographical locations. Closer to the equator, the speed will be higher, in the region of southern Europe it is 1200 km/h, this is the average Earth's speed in space.
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