A concept of the Russian successor to the ISS

OPSEK station

Artist rendering of the proposed orbital assembly workshop, the successor to the ISS, as it was envisioned around 2008 by Russian engineers. Instead of being a research lab, the new station was conceived as an assembly point for missions to Mars and lunar expeditions. Russia's next-generation transport ship can be seen approaching on the left. Copyright © 2009 Anatoly Zak

Russian-American cooperation on the development of the International Space Station, ISS, created great hopes for the future of the manned space program, but also left a bad taste in the mouth of both sides. From the outset, Americans grew impatient from depending on chronically underfunded Russian hardware, and the resulting bickering over money, while Russians have often felt taken advantage of in their desperate economic situation. Not surprisingly, as the ISS project had finally entered the assembly stage at the turn of the 21st century, the two sides started thinking about their separate ways in space.

In April 2001, the Russians, still shaken by the painful demise of the Mir space station, were facing a row with NASA over its objection to flying wealthy tourists to the ISS in order to obtain extra cash during the most difficult years of the country's economic transition. In the midst of the brouhaha, the head of the Russian space agency, Yuri Koptev, made the first public statement about a small Russian space station as a successor to the ISS. As had originally been planned for the Mir and Mir-2 projects, the new outpost would be placed into a high-inclination orbit so it could serve as a platform for Earth observation at high latitudes, encompassing most of the Russian territory. Koptev warned that the project would only become possible if and when Russia emerged from the economic black hole it was in at the time.

In November 2004, Nikolai Anfimov, the head of TsNIIMash, the Russian space agency's think tank, revealed a possible architecture for such a station, which showed what looked like a backup version of the FGB orbital tug docked with a science and observation module. At that point, remote sensing of the Earth surface appeared to be the chief justification for the future station. However as Russia started recovering from its economic crisis, more ambitious goals came to the forefront of the project.

Speaking at the 5th International Aerospace Congress in Moscow on August 29, 2006, Vitaly Davydov, deputy chief of the Federal Space Agency, said that Russia planned to abandon the International Space Station sometime between 2015 and 2025, and replace it with a domestically developed outpost in Earth's orbit. According to Davydov, the new station would be inserted into a high-inclination orbit, which would enable its crew to observe most of Russia. At the time, cosmonauts onboard the ISS could only see a small fraction of the Russian territory due to the station's orbit, which had been compromised to allow cooperation with the United States. (Launches from Cape Canaveral would not be possible into the high-inclination orbit which Russia planned for the Mir-2 space station before abandoning the project for the ISS in 1993.) According to Davydov, the orbit of the new station would have an inclination of 70 degrees toward the Equator, as opposed to 51 degrees for the ISS.

Along with its role as a remote-sensing platform, the future station would be used for material processing research and the development of technologies for manned missions to the Moon and Mars, Davydov said. Prior to the development of the new station, Davydov promised to complete the Russian segment of the ISS by 2011. One of the new elements of the ISS would be an Oka-T free-flying module dedicated to the material processing research.

On August 31, 2007, at a Roskosmos press-conference, its head, Anatoly Perminov, unequivocally described the purpose of the Russian successor to the ISS as an assembly platform for deep-space transport ships heading to the Moon and Mars. However, he added that the future station was still aimed for a high-inclination orbit to enable global remote-sensing of the Earth surface. In April 2008, Perminov reiterated the agency's goal to replace the ISS with an all-Russian station. Perminov said that the latest meeting of the nation's Security Council had approved the plan in general, without however setting a timeframe.

In January 2009, Aleksei Krasnov, the head of manned space flight directorate at the Russian space agency, echoed his boss, saying that the future Russian space station in low-Earth orbit would serve as a foundation for the lunar program and, later, for expeditions to Mars.

At the time, the agency aimed for 2020 as the launch date of the new Russian outpost, to coincide with the expected deorbiting of the International Space Station. Krasnov stressed however that the project remained an unfunded proposal under evaluation by the Russian government. In any case, it was clear that the lifespan of the International Space Station would determine when, if ever, the new orbital facility would go into orbit.

The OPSEK project

By 2008, the Russian successor to the ISS was identified as Orbitalniy Pilotiruemyi Eksperimentalniy Kompleks, OPSEK, or Orbital Manned Assembly and Experiment Complex in English.* Unlike the previous designs of Mir, Mir-2 and the ISS, the heart of the station would be a four-ton ball-shaped Node Module. Equipped with six docking ports, this relatively small and simple element would be the only permanent element of the station. All other modules would come and go as their lifespan and mission required.

The initial architecture of the OPSEK complex would be built out of modules originally planned for the Russian segment of the ISS. The exact scenario of the OPSEK assembly would depend on the end of the ISS and the readiness of the latest Russian modules. According to a 2008 scenario, the MLM multipurpose module, the node module and a pair of NEM power platforms would be first launched to the ISS in 2011, 2013 and 2014-2015, respectively. With the deorbiting of the ISS looming around 2020, these modules would separate from the old outpost to form the core of the new Russian station.

Another, more controversial scenario considered the separation of the practically entire Russian segment, including the MIM-2 docking compartment and the Zvezda service module, prior to the ISS deorbiting. In this case, the 20-year-old service module would temporarily take the responsibility for the flight control of the OPSEK, until its replacement with a 40-ton versatile core module, UMB, launched by a next-generation rocket from a yet-to-be built launch site in Vostochny during the 2020s.

The separation of the Russian segment from the ISS would leave the rest of the outpost without effective orbital maneuvering capabilities, leaving the European ATV spacecraft as a likely candidate to perform the tasks of attitude control and deorbiting. To achieve this the ATV would have to be modified to enable its docking with the US segment of the ISS.

Depending on the operational orbit selected for the OPSEK, it might be necessary to change the orbital inclination of the modules departing the ISS and forming the new station. The lowest inclination accessible from Vostochny is 51.7 degrees, while the ISS is orbiting the Earth with an inclination of 51.6 degrees toward the Equator. It is estimated that one or two Progress cargo ships would be necessary to push the modules from one inclination to the other.

From official statements during 2008 and 2009, it is clear that one of the chief objectives of the OPSEK complex would be support for expeditions to Mars. All major elements of the Martian expeditionary complex, such as the main habitation module, Mars lander and nuclear-powered space tug would dock to the station before their departure from low-Earth orbit toward Mars. The Martian expedition would return to the OPSEK as well.

The station would also play a similar role in lunar exploration. Reusable space tugs could link OPSEK with the Lunar Orbital Station, (LOS), in orbit around the Moon, thus creating a transport chain for a permanent lunar base. Such tasks as the servicing of modular satellites by orbital tugs based at the OPSEK complex were also cited.

In broader terms, TsNIIMash research institute, a chief strategist of the Russian space agency, formulated the OPSEK concept as a foundation of the nation's space strategy. By 2009, the new station was seen as the cornerstone of a new space exploration plan, which extended four decades into the 21st century. The ambitious program apparently included manned missions to the Moon, Mars and beyond. (344)

Cooperation with Europe and the US

In 2008, Russian plans for maintaining presence in the low-Earth orbit in general and the creation of a successor to the ISS in particular, had been met enthusiastically in Europe. As ESA had little hope to match the US effort to return to the Moon at the beginning of the 21st century, preserving a destination in low-Earth orbit seemed critical for the political support of the manned space flight on the continent.

In June 2009, Simonetta Di Pippo, ESA director of human space flight, told the editor of that she shared the Russian vision of the future space station as a platform for deep space missions. "I have continuous consultations with officials in Russia. We meet every month, month and a half, and now we are going to start jointly, the study how to proceed beyond 2025, Di Pippo said, ..."and we have a common idea that we would like to preserve presence in the lower orbit. We are studying different scenarios, whether we need permanent presence or, maybe, a human-tended capability, and we can end up with a totally different solution in the end, but I don’t believe we can leave Earth orbit."

Di Pippo also said that although current NASA plans for return to the Moon reserved no essential role for the station, it could change in the future. "Even on the NASA side, they have too many different developments (associated with the Earth orbit), including commercial involvement, which they can not immediately give up," Di Pippo said.

By the end of 2010, all partners in the ISS project were expected to agree on an extension of the ISS lifespan from 2015 to 2020 or even 2025. Once end of life for the ISS had been decided, active planning for post-ISS manned space flight could begin in Russia, Europe and possibly the US.

During 2009, Russian and European space officials started consultations on possible goals for manned space flight after the end of the International Space Station, ISS, program.

At the forefront of the talks were Russian plans to replace the ISS with a new manned outpost in low Earth orbit in 2020-2025. However unlike the ISS, which was designed to serve primarily as a research lab, the new station was conceived as an assembly point for missions to the Moon and Mars. Russian and European officials said they hoped that NASA would also be interested in the project.

In a presentation made to NASA, on June 17, 2009, Roskosmos officially informed the US about its intention to "build and prepare for operation the first elements of the orbital assembly and experimental piloted space complex by the end of the ISS life cycle."

After 2020

With the 2010 decision to extend the life span of ISS to 2020 and possibly as far as 2028, the OPSEK project had to be pushed back accordingly. Still, subsequent statements by Russian space officials confirmed that the project remained on the books. In September, the head of RKK Energia, Vitaly Lopota, told the semi-official Interfax news agency that the Russian segment of the ISS would be reconfigured into an autonomous orbital complex, which would function for another 10 years. In the meantime, the construction of the OPSEK complex should be completed in 2031, Lopota said.

*Other sources interpreted "E" in the OPSEK abbreviation as standing for "Ekspluatatsionniy" ("operational" or "exploitational") rather than "Experimental."

Chronology of the OPSEK project

2001 April: Yuri Koptev, head of Roskosmos, reveals plans for a Russian-built space station to succeed the ISS.

2004 November: Nikolai Anfimov, the director general of TsNIIMash, presents plans for a Russian-built station at the "NASA International Workshop on Creating New and Sustainable Space Exploration" in Washington D.C.

2006 Aug. 29: Russia plans to abandon the International Space Station sometime between 2015 and 2025, replacing it with a domestically developed outpost in Earth orbit, deputy chief of the Federal Space Agency, Vitaly Davydov said.

2007 Aug. 31: Anatoly Perminov, head of Roskosmos, describes the purpose of the Russian successor to the ISS as an assembly platform for deep-space transport ships heading to the Moon and Mars.

2009 June 17: In a presentation to NASA, Russian space agency, Roskosmos officially informed the US about its intention to "build and prepare for operation the first elements of the orbital assembly and experimental piloted space complex by the end of the ISS life cycle." (345)



Writing, drawings and animations by Anatoly Zak; last update: June 4, 2020

Editor: Alain Chabot; edits: July 7, 2009; April 4, 2011

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Watch the docking of Russia's next-generation spacecraft with the proposed OPSEK orbital complex in Earth orbit around 2020. Click to play. (Video is available in HD format) Copyright © 2009 Anatoly Zak

OPSEK as of 2004

A Russian successor to the ISS, as it was envisioned around 2004. Note what appears to be an Earth-facing radar antenna for remote sensing at the very bottom of the image. Credit: Roskosmos


An image which surfaced on the Internet illustrates a second phase in the OPSEK complex assembly, marked by the replacement of the Zvezda service module with the UMB module. Credit: RKK Energia


Russian concept of the orbiting station to replace the ISS, as it appeared in RKK Energia documents in 2008. Copyright © 2009 Anatoly Zak

Close up



A depiction of the OPSEK complex as of July 2010. Credit: RKK Energia


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