Moscow. September 17. INTERFAX - Recently, in the press, along with announcements about satellite launches, figures indicating the amount of "garbage" in space have increasingly begun to flash. Naturally, we are talking about man-made space debris. It is said about thirty thousand large (10-20 cm in size) fragments, almost a million smaller, but still very dangerous fragments larger than a centimeter and about a hundred million small fragments larger than a millimeter. They cannot destroy the spacecraft, but they can damage individual blocks.
On this topic, our special correspondent Vyacheslav Terekhov talks with Corresponding Member of the Russian Academy of Sciences, Scientific Director of the Institute of Astronomy of the Russian Academy of Sciences Boris Shustov.
In space, the "apple" has nowhere to fall
Shustov: Yes, in recent years the number of satellite systems in the world has increased significantly. Each has hundreds-thousands of satellites in service.
For example, the global satellite system Starlink already has almost five thousand satellites in space. And by the end of this decade, according to various estimates, the number of satellites in low orbits will be from 50 to 100 thousand! The population is growing, the needs for communication and, especially, Internet access are increasing, the number of satellites providing these services is increasing, and, of course, the risks associated with the appearance of man-made garbage are also increasing.
Correspondent: One hundred thousand satellites?
Shustov: Yes, yes, these are their plans. And the main thing is that they are not only on paper, but also in active development. The same Elon Musk launches 50 satellites every week.
Corr.: And why does he need so much?
SHUSTOV: This is a huge commercial program, Internet and fast communication all over the Earth.
Correspondent: And how many devices are there now that support the Internet in the world?
Shustov: Several thousand, that is, I would say six or seven thousand. Well, it's all changing up.
Reporter: And these satellites can't collide with each other? I understand that space, on the one hand, is comprehensive, but near-Earth space is small...
Shustov: It will happen sometime. Satellite collisions have occurred, as you know, and in the future this is an inevitable risk factor. The same Starlink performs several thousand evasive maneuvers of its spacecraft per month to avoid a collision. Several thousand! And this is generally a serious problem. So far, there have been no collisions of Starlink satellites, but it's a matter of time. When there are a hundred thousand of them, I'm afraid it will be impossible to avoid them altogether. Plus, collisions are not between themselves, but with the garbage that is already in orbit. This is almost inevitable.
Are there any space traffic regulations?
Correspondent: I understand that there are already more opportunities for collisions in space than on Earth. Don't you develop traffic rules?
Shustov: There is an information system and it is in principle mandatory. The orbital data is indicated. Of course, if the launch is carried out on a closed topic, then something is being kept secret, but still the data necessary for security is indicated. Can this be called a kind of rules of space traffic? It is unlikely, but there are still some rules: all launches must be registered. Otherwise, cosmic chaos awaits us, well, what does not happen in chaos?
Corr.: During launches - now not only we, but the Americans, China, India - coordinate the orbital data or only indicate them, warning, as in aviation, that flights there are dangerous?
Shustov: If the orbit is reported to you, then you yourself are unlikely to launch your satellite to it... However, if you have no interest in seeing what they have launched there. Otherwise, why take the risk?
Corr.: The problems of combating space debris are regularly discussed at international conferences. The last time, I know, there was such an international conference in Russia in 2019. Has anything changed since then?
Shustov: Firstly, there was another conference after it last year, because we agreed to hold them every three years. In addition, workshops and more special conferences are regularly held in our country. And abroad symposiums, conferences, etc. are held regularly. This is a necessity, because the picture of "traffic" in space, of course, is constantly complicated. This is due not only to the growth of satellite launches and the increase in the number of dangerous fragments of space debris for natural reasons. There are deliberate actions by countries that lead to a sharp increase in space debris. We should not forget that the launch of a satellite is also a demonstration of its military-technical maturity, and even more so its destruction by its own missiles. However, each such experiment leads to the appearance of thousands of new fragments, fragments of debris. The more fragments there are, the greater the danger of self-multiplication of space debris. Large fragments collide, producing a large number of smaller, but still very dangerous fragments. Those also collide and the process develops.
Reporter: Do you mean Kessler syndrome?
Shustov: Yes, everything happens according to the principle of a chain reaction. So, if the concentration of fragments reaches a critical level, then collisions will lead to their uncontrolled increase.
The new "Milky Way"
Corr.: What new has appeared on the issue we are discussing over the past three years?
Shustov: The most important thing is the appearance of the "new" Milky Way.
No, no, astronomers certainly haven't discovered a new galaxy. It is known that the country's leadership has approved the development of the Milky Way project aimed at ensuring the safety of space activities in near-Earth space. The system will consist of dozens of specialized ground-based telescopes and a space segment from a constellation of satellites that will allow monitoring near-Earth space. An important goal of this project is to track space debris in near-Earth orbits.
In addition, the state of space weather and radio interference conditions will be studied. For the first time in domestic practice, a project of this level also pays attention to small celestial bodies, in particular, the problem of asteroid-comet danger.
Correspondent: Is this the Russian national system?
Shustov: Yes. The Milky Way is being prepared under the auspices of Roscosmos.
Corr.: Even when listing the tasks facing the project, it is clear that this is an extremely costly project. Naturally, if the president approved the development of the project, then Roscosmos counted the money. And yet, as in that famous Vysotsky song, the question cannot but arise: "Where is the money, Zin?"
SHUSTOV: You are right, this is a very expensive event, and Roscosmos has prepared not just a concept, but a calculated project, that is, more advanced material. And if it is fully adopted, the system will be fully created. If, say, as it happens, there is not enough money, then the most important component of the project will be implemented.
I must say that the Milky Way program is open for scientific discussion, and it is already being talked about at various professional venues and scientific conferences.
A space debris trap or an inflatable balloon?.
Corr.: Two years ago we talked about the existence of such "traps" for space debris, have they already been created and are they operating?
Shustov: No, traps are not systematically used yet, they are only being tested. Design options are being selected. Nets and harpoons are used to catch fairly large objects, these technologies are being tested in England, Japan, and the USA. We are also considering methods of cleaning space from debris. For example, some time ago, the specialists of NPO Lavochkin proposed to attach a balloon - a folded plastic shell to a large object that needs to be taken from low orbit into the Earth's atmosphere. Gas is injected into it, the balloon inflates and the cross-section of the entire structure increases. This leads to accelerated braking and rapid entry into the atmosphere and subsequent combustion of the object being removed.
But this is only for low-flying vehicles. And for vehicles in high orbits, for example, on geostationary, a different approach. There, the main method of cleaning is removal to another orbit. That is, it is worth raising a spacecraft that has served its time three hundred kilometers higher, it is inexpensive in terms of energy, and it will no longer interfere for a very long time.
Before you launch a satellite, think about how to get it back!
Corr.: All we discussed was the fight against the existing garbage that is moving in space. Are there any preventive measures?
SHUSTOV: You mean the preparation of the satellite back on Earth. And such work is underway. There are certain technical rules. Now, in international terms, they are still acting in the form of a recommendation, but gradually they are already acquiring the nature of requirements. We are talking about the fact that each launch must ensure the removal of the spent device from orbit, that is, a certain block is provided in the design of the device, which is turned on at the last stages of the life of the device. A block means an engine and some kind of fuel reserve, most likely, and a control system that allows this device to be taken either to a higher orbit, if these were high orbits, or to be dropped into the atmosphere.
Such requirements are now becoming standard. I would not say that this is a strict law, but recommendations, but all solid players fulfill them.
Is the comet also garbage?
Correspondent: The Milky Way project also provides for the observation of comet-asteroid motion. Now, when some comet or asteroid approaches the Earth, are they tracked in the same way as space debris, or is there a separate system for them? The problem of space debris is more serious than asteroids or comets.
Shustov: Both problems require attention. Space debris is daily, dangerous asteroids and comets are much rarer, but the scale of the danger can be very serious.
In addition to man-made debris, there is always natural debris in near-Earth space, these are small fragments of asteroids or fragments of comets. And sometimes larger objects appear - asteroids and comets themselves.
The methods of their observation generally differ from the methods of observing space debris. Small debris is tracked mainly by radars. Since the distance to the garbage is not very large, usually up to a thousand kilometers, ground radars take it. Moreover, objects measuring a centimeter or even smaller are observed.
And the garbage that is in high orbits cannot be reached by radars, and is observed using telescopes in the optical range. It is clear that it is possible to observe only larger objects. Comets and asteroids are also observed using telescopes. But the mode of operation is different. Debris in near-Earth orbits moves at a higher angular velocity than more distant comets and asteroids, and shorter exposures should be used to observe debris. However, we delve into the technical details.
Interviewer: Do astronomers now see that an asteroid or comet is currently moving at a dangerous distance from the Earth or even towards the Earth? And is it dangerous?
SHUSTOV: Quite a lot of objects fly past the Earth all the time. Every now and then we read that an asteroid has flown or is flying near the Earth... It all depends on the size. Bodies up to a meter in size on average collide with the Earth every month or two, and in space up to the Moon, they fly every day, maybe even every hour. But such bodies are not dangerous.
And the bigger and more dangerous ones? They are being watched and there is no danger yet! You can enjoy life.