The disappearance of the Malaysia Airlines Boeing 777 on the night of 8-9 March this year has become one of the most mysterious events in aviation history. And regardless of how his search ends, one question will worry many people for a long time: how in the second decade of the 21st century could a huge plane disappear without a trace and for so long?
An abyss in an era when the news every now and then informs us that this or that person was discovered simply by the signal of his mobile phone. There were more than two hundred such phones on board the ill-fated flight MH-370 Kuala Lumpur - Beijing: 227 passengers and 12 more crew members. And where are the spy satellites that allow you to see individual people, where are the air defense radars?
Where did he go?
This bewilderment has become fertile ground for a variety of conspiracy theories: from cowardly suicide to kidnapping by the American special services and the mandatory in such cases by aliens. However, there were indeed grounds for conspiracy theories: the aircraft first stopped transmitting signals from the automatic ACARS system, which monitors flight parameters and transmits information to ground services, and then turned off transponders - radio transmitting devices that send information about the location of the aircraft and its identification (flight number).
The subtlety here is that the plane was disconnected from the ground sequentially, with an interval of a quarter of an hour, and then, about an hour later, was spotted by military radars. This excludes the version of instant death of the aircraft. The MH-370 flew to the west, that is, in a completely different direction than it was supposed to. The last data from him were the signals received by the communication satellite Inmarsat, they did not carry information about the coordinates, but according to the analysis of the signal, two theoretical arcs of its location arose: one over Asia, the other over the Indian Ocean. There was no more navigational information about the plane.
If we put aside the version of a grandiose conspiracy of special services on a worldwide scale, then the conclusion suggests itself very simple: we are able to quite confidently detect only what "beeps", that is, actively emits any radio signals. A "silent" body, even 60 by 60 m in size, may well be lost or hidden.
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Blinded radars
Civil aviation radars are of two types: primary and secondary. This is a tracing paper from the English terms: primary and secondary radar, since English is the international language in aviation. The most primitive in principle of operation, but they are also the most reliable, are primary radars, invented in the 30s of the last century. They send out a directed beam of radio waves. It is quite narrow and can be compared to a spotlight beam. The radio waves bounce off a flying plane and bounce back to the receiving antenna. The radar constantly revolves around its axis or sways back and forth - this is how the beam creates a certain picture.
Radars of this type are difficult to deceive, a special technology is needed, known as "stealth", because it involves the basic physical process - the fall of waves and their reflection. But the signal will say little about the reflective point itself - because it is just a reflection. But the secondary radar is another matter. In fact, this is a system for identifying "friend or foe", and it is precisely this system that informs the radar that requested it information about what is in the sky overboard. Obviously, this is possible only as long as this system is turned on. If you turn it off, the sky becomes empty.
The pilot of the Malaysian plane turned off the system, so only primary radars could detect it. But the primary radars of the airport rarely reach a distance of more than 240 km, and often their vigilance is barely enough for a shorter distance. The reason is simple - it is the curvature of the earth's surface. The longer the waveforms you use, the further the signal will go, but the lower the radar resolution will be. This is an important point - in simple terms, it is the ability of the radar to see two close-flying aircraft as separate targets, and not blind them into one.
One of the versions of the disappearance of flight MH-370 is based on this technical nuance. According to this theory, the pilot of the MH-370 settled behind a similar Singapore Boeing-777 of the Singapore Airlines company, which was flying SA68 from Singapore to Barcelona. Supporters of this version believe that it was enough for the Malaysian to keep about 500 feet behind the Singaporean with the emitters turned off and no primary radar station would separate them - one point would move on the radar screens. Having flown over India and Pakistan, the MH-370 could go on an independent flight.
White line - confirmed route MH-370. The blue sector, limited by a dotted line, is a possible water area over which it flew. Green lines - airways
As for the Boeing's flight to the south, it is clear that it was in an area where, although there are regular airlines, the intensity of air traffic is low. The route of the proposed flight is significantly west of the coast of Sumatra and Java, there has been no military threat from that direction since the Second World War. There are simply no military long-range radars. And the MH-370 pilot knew this very well, there are no secrets in this information.
Marine Observer
On the other hand, one can ask the question: how intensive is the shipping there? Could sailors see the plane visually or on radar screens? There is shipping there - it's true. From the western vicinity of Australia to Sri Lanka and India, as well as from Africa in the direction of Java and Sumatra, sea routes run. Perhaps there someone could see a low-flying plane, because no one would have paid attention to a point in the sky. Of course, if the plane flew extremely low, burned, then the sailors would immediately send a distress signal and hurry to the crash site. But that would be a fantastic coincidence.
White line - confirmed route MH-370. The crimson sector, bounded by the dotted line, is a possible area over which he flew. Multi-colored lines - sea routes, the brighter - the more active
The radar also hardly helped the sailors. The so-called radiation pattern of marine radars is directed horizontally, as if sweeping the surface of water and land. The aircraft in the sky will not be seen by the marine radar, unless it will fly at a very low altitude. I have seen how a signal is reflected from a large helicopter flying in a distant intersecting course - there were several points of light, and that was all. So here, too, the probability of fixing this plane was extremely small.
It is also important to pay attention to the fact that the routes of sea vessels are by no means accidental. They are designed to optimize arrival times and fuel consumption. Sea routes, like air routes, are invisible, but quite real, and in the event of a hijacking of an aircraft, it is quite possible to plot a route so as not to intersect with other vehicles. But what are the satellites for?
By the Paganel method
To begin with, many for some reason are convinced that the receiving devices of users (GPS, GLONASS or Galileo) themselves emit something. Unfortunately, this is not the case for rescuers. They are just receivers, and finding the owner's location using them is like looking for the location of a radio listener armed with a conventional transistor. Where he listens to us - God knows …
It's another matter if you combine a GPS system with a radio transmitter, which we have in our smartphones or remote search systems. But flight MH-370, as we remember, was in total radio silence. Almost total - once an hour the device of the Inmarsat satellite communication system worked. It does not give coordinates - it's just a signal that the plane is alive, but Inmarsata specialists were able to analyze the signal to find out at what angle the signal came to the satellite hovering over the Indian Ocean. Hanging is not a figure of speech: being in a geostationary orbit 36 thousand km above the Earth, it is really motionless relative to the same point on the planet.
The very fact of determining the approximate position of the aircraft using only one signal is already considered an unparalleled success.
Remember, in the wonderful work of Jules Verne "Children of Captain Grant", the French geographer Jacques Paganel led a rescue expedition at 37 degrees south latitude practically around the entire planet? At first, Inmarsata specialists received just such a gigantic circle of 40 degrees from the vertical.
But the analysis of the signal properties first showed that it makes sense to talk only about two arcs: over Asia and the Indian Ocean. Then the northern arc was also excluded from consideration. Only the southern one remained. And taking into account the time of the last "ping", the search area was determined. By the way, its area is larger than the area of Ireland. This is the margin of error when the target is barely audible. But she should have been visible …
I can see what from above?
We read about the excellent resolution of today's satellite systems. For example, DigitalGlobe, which posted its images for a general search for the missing plane, has a resolution of 41 to 82 cm. aircraft planes. If not for one "but".
DG satellites fly at altitudes of 680 and 770 km. To take a high-quality picture, they use optics that simultaneously cover a square with a side of 15 by 15 km or more. What lies outside this square goes unnoticed.
To scan the entire surface of our planet, satellites fly in polar orbits, that is, over the poles of the Earth. It rotates, and the WorldView-2 satellite, making one revolution around the planet in about 100 minutes, each time displaces at the equatorial latitude by more than 2700 km (see Fig. 4). The two satellites cut the gap in half, and yet huge empty spaces are formed between their projections on Earth.
The satellites, rotating, gradually fly over the entire planet, but large gaps remain between the photographed routes
And the plane does not stand still. He moves at a speed of 700-900 km per hour, which means that the chances of photographing him are extremely negligible. Moreover, a satellite is not an airplane that can easily change course. Celestial mechanics makes bodies move along invisible, but very rigid gravitational rails, and experts can say for sure when a particular satellite will be above a particular point on the earth's surface.
Peekaboo
It turns out that while the one who wants to hide, it may well do it. For example, the military with its mobile missile systems can secretly move - after all, even if it is found by satellite, it has time to hide. Moreover, he will not run away at random, but knowing where the chances of getting into the field of vision of a celestial observer are the smallest. The main thing is not to go on the air.
But, as you can see, not only the military can disappear in an unknown direction. We do not know whether the disappearance of the Malaysian plane was voluntary or involuntary, but it is already clear that such opportunities exist. And if they are, then most likely someone will definitely decide to use them.
The loss of flight MH-370 is a grandiose anti-advertising of world civil aviation. This is exciting news for terrorists and maniacs. Well, the world superpowers can see how far-sighted the Chinese were, who demonstrated in 2007 the destruction of satellites in orbits that use reconnaissance vehicles.
A 21st century war can begin and end in space if one of the parties can deprive a more technologically advanced adversary of their space advantage. To paraphrase a famous American proverb, the Chinese can say that "space interceptors equalize the chances." And when everyone returns to the 20th century, it will be difficult to say which side the truth will be on. These are the futuristic jungles that have led to speculations about the reason for the loss of the ill-fated Malaysian plane.
