The closer the planned decommissioning date of the International Space Station, the more actively there is talk about an alternative to it. They offer a variety of options.
What awaits the ISS
The International Space Station is one of the greatest achievements of humanity. The joint project brought together 14 countries of the world: the Americans played the leading role in the implementation of the plan, and most of the ISS modules belong to them. The International Space Station has become the largest OS ever created.
Its predecessor, the domestic Mir, was several times smaller and significantly inferior in capabilities. However, all good (as well as bad) sooner or later comes to an end, and the ISS in this sense was no exception. It is planned to decommission it in 2024. The main reason is the high cost.
Each year NASA spends about $ 3-4 billion on the management of its ISS segment. This is approximately half of the total budget allocated by the US government for manned space launches. Well, the total cost of the ISS project has long exceeded $ 100 billion.
Launched in 1971, the Soviet spacecraft Salyut-1 became the first single-module orbital station in history. It was created under the Long-Term Orbital Station program. The basis of the apparatus was the working compartment: a cylinder of small diameter. The Americans "pulled up" a little later - they launched their first orbital station "Skylab" in 1973. It is also noteworthy that the USSR was the first to create the Mir multi-module manned orbital station, which began to operate in 1986.
But not everything is as simple as it seems at first glance. After 2024, the station can be transferred to private hands. By the way, back in 2016, the private company Bigelow Aerospace installed an experimental residential inflatable module BEAM (Bigelow Expandable Activity Module) on the ISS. Such structures can become an integral part of the station. Bigelow Aerospace, by the way, has proposed a version of its own "inflatable" orbital station, but this is still only a project, and we will not dwell on it now.
By the way, the price became the main, but far from the only reason for the planned abandonment of the ISS. Everything is much deeper: why do we need such stations at all? American professor Robert Park said that most of the planned scientific experiments are not very important for world science. The scientist notes that the purpose of most scientific research in the space laboratory was to conduct them in microgravity. But all the same can be done much cheaper under artificial zero gravity conditions on our native Earth. It would cost tens and, probably, hundreds of times cheaper than the experiments carried out on board the station.
So what's the point of the ISS? First of all, the project showed that the leading countries of the world are ready to cooperate in solving incredibly technically complex problems. The International Space Station can be perceived in a different light - as the first step towards human life in orbit of the planet. This means not just astronauts staying there in order to carry out scientific missions, but the full-fledged life that we lead on Earth.
Artificial gravity as salvation
Back in the second half of the 20th century, projects appeared involving the creation of real cities in orbit. You can, for example, recall O'Neill's "Island", "Bernal's Sphere" or "Stanford Torus". All of them were giant artificial gravity orbital stations designed for thousands of inhabitants. It seemed that each of these space megacities could provide for itself (which, of course, is very important in the context of "independence" from the Earth).
Now these projects seem to the world community to be too complicated, expensive and even naive in their own way. However, experts from Washington DC United Space Structures Bill Kemp and Ted Mazeyka do not seem to think so. In any case, their projects are clearly created under the influence of the "titans" of the past years. These experts proposed a whole family of stations: the diameter of the smallest will be 30 m, and the diameter of the middle one - 100 m. It is with the latter option that the greatest hopes are pinned. Anyway, DC United Space Structures presented images of this station and diagrams of its internal structure. According to American scientists, in order to protect a large space settlement from radiation, it is necessary to apply passive protection, the weight of which would be 4.5 tons per two square meters of outer walls. In other words, the total weight of such protection will be almost 10 million tons. Naturally, the task of delivering such an incredible cargo into orbit is daunting, and it cannot be accomplished at the current level of technological development.
We are talking about a huge space "mushroom", against the background of which even such a rather large spaceship, like the Space Shuttle, will seem like an insect. But, in general, the development of DC United Space Structures is rather a "compromise" between the ISS and giant orbital cities. The diameter of the space "mushroom" is 100 m, the length is 500 m. The International Space Station has more modest dimensions: its length is slightly more than 100 m, and its width is 50 m. 3 thousand times the volume of the ISS. On the other hand, for example, the DC United Space Structures project cannot compare with the Bernal Sphere either, because its diameter, according to the idea, was supposed to be an unimaginable 16 km. And such a city could accommodate from 20 to 30 thousand inhabitants.
With all this, the "mushroom" inherited the main "chip" of old projects - artificial gravity. It will be created by rotating the station around the central axis. The rotation speed will be 4.22 rpm. This will create centrifugal force, allowing everyone on board the station to avoid weightlessness and feel at home.
The role of the concept can hardly be overestimated. Of course, one can get used to weightlessness, but it will be much harder (or even impossible) to perform the usual actions. Warming up food, taking a shower, going to the toilet - all these things familiar to earthlings are not so easy to do on board the ISS. And also weightlessness has a negative effect on the human body as a whole. One of the most unpleasant effects of weightlessness is rapid muscle atrophy, followed by a decrease in the basic physical parameters of the body. At the International Space Station, special simulators are used to solve this problem, but, of course, it would be preferable to avoid such difficulties at all.
We add that we do not know very much about the long-term problems of being in zero gravity. Many Soviet cosmonauts and American astronauts have been in space. And many times. But they haven't lived there for years. But projects like the one conceived by DC United Space Structures imply just such an approach. “If we want to stay in space for more than a year, we need to make an artificial gravity system, or we will sacrifice people in the process,” says Bill Kemp, founder and CEO of United Space Structures. It is assumed that the station with a diameter of 30 m will maintain gravity at 0, 6 Earth. According to calculations, this will be enough for a normal life on board for two years. “The direction of rotation of the cylinder doesn't matter,” says Kemp. "The speed depends on the radius of the rotating object and the gravity you need: the larger the radius, the lower the speed of rotation."
You will still need to get used to the conditions of the space "mushroom", because artificial gravity has noticeable differences from its "natural" counterpart.So, a walk in the direction of rotation of the station will be similar to descending a slope and the floor will "go away" from under your feet. If you go in the opposite direction, you will get the feeling that you are climbing mountains. But with a walk perpendicular to the rotation, the astronaut will think that he is falling to the side.
The main cylindrical body of the orbital station (the "mushroom stem") will rotate in one direction, and the dome ("cap") - in the opposite direction. This design is necessary for the further arrangement of the docking module, which will receive spacecraft. The station will be constructed using composite materials, some of which are yet to be created.
At the base of the "mushroom" there will be equipment for collecting space resources, which contain, for example, comets or asteroids. Then - a section where several spaceships will be waiting, for example, for a flight to the Moon or Mars. In the images presented by DC United Space Structures, the spacecraft have a futuristic appearance: now nothing like this exists.
Further - the production facilities. Microgravity will provide unique conditions for production, so the benefits of the new station will be difficult to overestimate. The creators of the station have not forgotten about entertainment either. Closer to the "hat" of the giant "mushroom" will be placed a hotel, a 3D arena and other places for fun. Obviously, neither the station staff nor the tourists will have to get bored. Finally, the largest part of the station - its dome - will serve as a place to grow food for the crew, which is extremely important in the framework of the concept of self-sufficiency. In addition, it is in the dome that the command center, the equipment necessary for the work of the station's crew, and a rescue ship will be located, which in the event of an emergency will deliver people back to Earth.
Don't forget about scientific research. The unique conditions of the station will help to better understand the climate change taking place on Earth. The orbital station can also become a platform for revolutionary research in the field of biology and medicine. For the first time, the truly long-term consequences of a person's stay outside their home planet will be studied. In general, there are a lot of options for using the space "mushroom". True, unlike O'Neill's "Island", "Bernal's Sphere" or "Stanford Torus", it cannot be viewed as a kind of new world where civilization would find its salvation in the event of a global planetary catastrophe. Still, the scope of the idea is very different. And the dependence of the promising orbital station on the Earth will be much higher. Recently, a representative of the British Interplanetary Society, Jerry Stone, spoke about a project that the organization is currently working on. We are talking about a huge space city - an enlarged analogue of the ISS. According to the plan, the cylindrical space colony will reach a diameter of slightly less than 6.5 km, and its length will be 32 km. Thousands of people will be able to live and work on board the giant space station.
When exactly is it planned to build the station? There are no specific plans in this regard. Construction, according to preliminary data, will take about 30 years: this is 3 times longer than it took to build the ISS. And the estimated cost of the project is immeasurably higher - $ 300 billion.
But how exactly will the DC United Space Structures station be built? According to the idea, special insect-like robots are used for this. They will have many "hands" to carry out a wide variety of tasks in orbit. Such devices do not exist now, but the concept of orbiting construction robots has been used for many years. So, when creating the ISS, "Kanadarm" and "Kanadarm-2" were used. The latter robot plays a key role in the assembly and maintenance of the space station.It moves equipment and materials within the ISS, helps astronauts work in outer space, and maintains instruments and other payloads that are on the surface of the station. For the manufacture of construction robots, as well as the "mushroom" station, they plan to use the latest composite materials.
A problem with many unknowns
The project from DC United Space Structures is, in fact, just a bold initiative. Well-developed design project. The creators themselves note that they do not yet have the opportunity to answer all the technical challenges. It is not entirely clear how exactly the radiation protection will be achieved. The developers hope that the corresponding technologies will be created in the future. In the meantime, this question remains open. A large station will also need good protection from cosmic dust and debris, which is becoming more and more in orbit. To make it clear, now there are about 17, 8 thousand relatively large objects, the size of which is 10 cm. If we talk about small ones (from 1 mm in size), then their specialists number more than one billion.
Until recently, the hopes of the Russian cosmonautics were associated with the promising module "Science" for the ISS. The 24-ton module was sometimes also considered as the basis for a future "national Russian station", which so far only exists in deep theory. Now, during the construction of the module, contamination has been found in its fuel tanks: this will require cleaning and, possibly, recycling of many systems. Given the financial difficulties in the Russian space industry, the module will most likely have to be abandoned altogether.
How dangerous is it? In 1983, a miniature grain of sand, approximately 0.2 mm in diameter, left a serious crack and depression with a diameter of 0.4 mm in the Space Shuttle's window. Much later, in 2016, a centimeter pothole was found on the glass of the window of the International Space Station, supposedly left by a tiny piece of paint or metal. In other words, at an orbital speed of more than 27 thousand km / h, even a ten-centimeter fragment can become fatal for the station. So the risk for the ISS, despite the serious protection, is very high. What then can we say about a larger object, on board of which there are thousands and thousands of people?..
But a much more complicated issue is related to the financing of the "mushroom" station. You don't have to count on him at all. The main goals and objectives of international cosmonautics have long been defined. Now these are flights to the ISS, and tomorrow - the exploration of the Red Planet. In between, they are trying to squeeze in projects of stations that are less expensive than the ISS. More and more often, for example, they talk about the lunar orbital station - a smaller analogue of the ISS in orbit of the natural satellite of our planet. But these are only plans so far, and it is not a fact that they will come true. There is no need to talk about a giant orbital station, several times more expensive than the ISS. So concepts are concepts, and reality is not yet too much in favor of such projects.