Exactly half a century ago, on April 19, 1971, the first manned station in the world, Salyut-1, was launched into space in the USSR. And on Sunday, Deputy Prime Minister Yuri Borisov said that in three years Russia will leave the ISS project and will build a new station in orbit only on its own. Thanks to what Russia still retains priority in this type of space exploration?
The Soviet Salyut-1 was originally designed and assembled as a military orbital station, although the first station in the USSR was launched in a truncated, “civilian” version. There were good reasons for such a “military approach” of the Soviet Union: in December 1963, the US public presented a project for an orbital station MOL (Manned Orbiting Laboratory), which involved the creation of a manned station for reconnaissance activities with the ability to remove from orbit or destroy enemy satellites. Due to the limitations of the US space program in the early 1960s, the MOL turned out to be “one-off”, and much of its design was borrowed from the Gemini spacecraft and the upper stage of the Titan IIIC launch vehicle.
However, by the mid-1960s it became clear that MOL was clearly lagging behind the leading edge of the American space program, which received such a powerful launch vehicle as Saturn-5 thanks to the “lunar race”. Therefore, in a test version, the MOL was launched only once – in November 1966, using the already flying capsule of the Gemini-2 spacecraft. During this launch, the Gemini capsule performed a suborbital maneuver and successfully splashed down after half an hour, and the MOL station mock-up was able to actively work in orbit for 30 days. However, this was not enough to support the program – and in June 1969, the closure of the US military space station project was announced.
In the USSR, the stations of the Almaz program, which later became known as Salyut-2, Salyut-3 and Salyut-5, were developed at the Moscow Region OKB-52 under the leadership of Vladimir Chelomey. “Almazy” were designed to solve the same tasks as MOL, that is, to conduct photographic and radio-technical reconnaissance and control from orbit by ground military means. For these purposes, the stations were supplied with a telescope-camera and a set of long-focus cameras.
Since the USSR did not know in detail about the US military plans at that time, the Almazy even equipped the modernized HP-23 aviation cannon (the Shield-1 system), which in the future was to be replaced by the Shield-2 system, consisting of two space-to-space rockets. With the help of these weapons, “Almazy” were supposed to protect themselves from US survey satellites and orbital interceptors, as well as to prevent the potential use of American space shuttles to “kidnap” Soviet military stations from Earth orbit.
Thus, only Salyut-1 and Salyut-4 were purely civilian stations in the first series of the USSR, which also largely inherited the units and parts of military stations of the Almaz series. It was the Cold War that helped create the first manned orbital station, in the launch of which the USSR received an undoubted priority.
The era of “Salutes” and “Peace”
Leaving the purely military program “Almaz” outside the framework, then the Soviet orbital stations had a fairly clear and logical path of development, along which all other countries eventually followed.
Already on “Salyut-4”, which was launched into orbit in December 1974, the main problem of the first generation stations was revealed – they had only one docking station. This limited both the time of visiting expeditions and the opening hours of the station itself. A manned spacecraft with a crew could not bring significant amounts of water, supplies and fuel to the station to raise the station’s orbit. As a result, after the depletion of its own fuel reserves, the station inevitably left orbit after decelerating on the residual Earth’s atmosphere at altitudes of 180-200 km. Nevertheless, Salyut-4 set the record for the duration of stay in orbit (770 days) and the record for the duration of the visiting expedition on the Soyuz-20 spacecraft, which was 90 days.
The Americans faced similar problems when using their stations. Despite the fact that their Skylab station, launched in May 1973, was able to operate in orbit for a full six years, the duration of the longest visiting expedition on the Apollo spacecraft was only 84 days. In the absence of supply ships, the Americans until the very last tried to keep Skylab in space until it became possible to deliver a propulsion module for raising the orbit using the new Space Shuttle shuttles. However, these plans were not destined to come true – in July 1979, “Skylab” left orbit.
In the USSR, the stations “Salyut-6” and “Salyut-7”, which were developed by the Design Bureau im. Queen, already had two docking nodes. This arrangement made it possible to simultaneously receive two spacecraft – for example, two “Soyuz” with the main expedition and the visiting expedition. In addition, the second-generation Salutes were equipped with their own propulsion system, which could be repeatedly refueled from unmanned cargo ships of the new Progress series. Progress also brought new regenerative cartridges for CO2 utilization, compressed gases, drinking water, food and other consumables for the station. New scientific equipment was delivered on transport ships, and the results of experiments were delivered to Earth. On the new Salutes, the cosmonauts had every opportunity to carry out maintenance and even repair the station.
It was the presence of two docking nodes and a refueling system that removed all restrictions on the duration of the station’s operation in orbit – now this time was limited only by their resource. As a result, Salyut-6 was able to operate in orbit for 1764 days, of which 683 days were manned flights, and Salyut-7 lasted 3216 days in space, of which 816 days were manned flights.
Another step in modernizing the type of stations is associated with Salyut-7. In February 1985, after a six-month absence of people at the station, communication with it was interrupted. A special rescue expedition undertaken on the Soyuz T-13 spacecraft with Vladimir Dzhanibekov and Viktor Savinykh was able to bring the station back to life, but the question arose that even the most advanced automation could fail in orbit in the absence of people at the station … This became the decisive argument confirming the correctness of the already planned decision – the new Salyut-8 station, which later became known as Mir, received six docking nodes at once. This made it possible to achieve almost complete habitability of the station: it spent 5514 days in orbit, of which 4294 – with a crew.
ISS, its future and plans for new stations
The next, already Russian development, which at first bore the name “Salyut-9”, and then – “Mir-2”, as a whole repeated the principles laid down in the first “Mir”. Designed as a base unit for the unrealized Russian project of the Mir-2 orbital station, the station was eventually launched into orbit as a life support module Zvezda and became the main part of the Russian segment of the new International Space Station (ISS).
By now, Zvezda has been in space for almost 21 years and is the third oldest unit, after the Russian Zarya unit and the American Unity unit. Until now, Zvezda is one of the main space “berths” of the ISS, which is facilitated by the fact that its intermediate chamber is similar to the structure of the “Mir” and includes three docking nodes. By the way, this fact may have become the reason for the notorious air leak, since it was Zvezda that assumed all the main loads when correcting the ISS orbit with the help of Progress cargo spacecraft.
The age of the main blocks and the inevitable deterioration of the ISS are also associated with the main concerns regarding the future of the station. At this time, the project participants have agreed on the financing and operation of the ISS through 2024, inclusive, and the previous US administration was strongly opposed to extending these deadlines. Since the American contribution to the ISS is quite significant, this actually puts an end to the existence of the station as an international site. In other words, after a long coexistence of Russia and the United States, one way or another, a civilized space divorce concerning the ISS will have to be carried out.
Moreover, the last meeting with President Vladimir Putin, which took place on April 12, Cosmonautics Day, clarified Russia’s position on the ISS. Russia also decided to support the ISS until 2024, after which it will start building its own station. On April 18, this was announced by the profile Deputy Prime Minister Yuri Borisov.
However, in 2021 it is planned to dock to the ISS a new multifunctional module “Science”, which will be installed in place of the service module “Pirs”, which was previously used for spacewalking. After docking with the ISS module “Nauka” to the Russian segment in 2022, they intend to dock a new nodal module with additional docking nodes in order to solve the existing problems of “Zvezda” with its help. In addition, in 2022, the scientific and energy module “NEM-1” will be launched to the Russian segment of the ISS.
All this will allow, in the worst case scenario, to continue the operation of the Russian segment of the station even after the possible withdrawal of the United States from the project and the highly probable growth of problems with the state of Zvezda. In the worst case scenario, it will be possible to disconnect the Russian segment of the ISS and continue its operation as the backbone of the new Russian station – fortunately, the Russian segment is self-sufficient.
There are no hopes for the salvation of the American segment: by 2024, the American company Axiom Space plans to dock the first commercial module to the Harmony module, and to it – two more, which are planned to be used for space tourism. After the possible closure of the ISS project, these modules are planned to be equipped with an independent life support system and used as a commercial orbital station.
And finally, there are two plans for the complete replacement of the ISS.
In Russia, it is a preliminary design under the working title “Salyut-10”, which is supposed to be the base unit of the new Russian orbital station. So far, Roskosmos has not allocated funding for these purposes, which is pushing the timeline for the implementation of such a project beyond the border of 2025. However, a new base unit for the station is simply necessary – after all, the existing “Zvezda” has clearly exhausted its resource, which is still being extended by various technical tricks.
The Americans also have a plan to replace the ISS. This is the project of the LOP-G (Lunar Orbital Platform-Gateway) station, which is planned to be placed in circumlunar orbit. Such a station will make it possible to engage in a detailed study of the Moon and the specifics of the long-term stay of people in deep space, and in the future it can be used as a transfer station for astronauts on Martian expeditions. In the case of the construction of LOP-G in the United States, they have already announced that they are not interested in supporting the ISS, which is indicated through the inevitable withdrawal of the United States from this project – either in 2024, or at least in 2028.
So far, the first launches under the LOP-G program are scheduled for 2022, but they all rely on the availability of a new SLS carrier in NASA’s assets, whose first flight is due to take place this year. So while the United States is in no hurry to close the ISS – after all, as has often happened before, it is better to have a working station in orbit than very beautiful plans for the supposedly “inevitable” future.
Thus, after 2024, four manned space stations may appear in space at once: a Russian and a private American station in near-earth orbit, a NASA station in a circumlunar, and also a new station that China wants to launch into Earth’s orbit. Humanity does not leave space, and manned stations remain a symbol of its presence in it. Including the presence of the Russian one.