Due the fact that International Space Station will reach to the end of its operational life in 2028, Roscosmos unveils different plans for replacing ISS. Recent concept refers to space station designed and operated only by Roscosmos - now idea has changed.
Considered as Russian replacement for ISS and planned for starting on 2031, OPSEK was basing on Russian ISS modules - Zvezda, Poinsk and Nauka (Nauka is still not launched with mission planned on 2017). Roscosmos considered cooperation with foreign partners, mainly ESA and NASA. Main difference to ISS was fact that OPSEK was not designed as space laboratory, but as space facility for assembling future spacecrafts for Moon and Mars missions. Due the differences and not meeting demands of NASA (which already had quite detailed plan for Mars mission) and ESA (which was rather interested in unmanned Mars missions), Roscosmos was continuing development of the OPSEK for its own. Usage of Zvezda, Poinsk and Nauka was smart move to reduce costs and was planned to give continuity of Russian presence in space but also limited range of modernization in future station. Even most recent Nauka module in 2031 - when OPSEK should start - would be outdated and should be replaced with new module. Costs for start would be lower comparing to cost of new station, but costs of exploitation would be increasing faster. That is mainly why Roscosmos is looking for partners for their venture.
According to Tass news agency, Roscosmos is still open for propositions for cooperation under the project of new space station, OPSEK. It seems that it will not be pure Russian project as it was recently planned. Today, on March 30, 2016, chief of Roscosmos, Igor Komarov declared that Russia is ready for cooperation:
"There is an understanding that we’ll continue developing the project jointly in the future. We have agreed that a club of countries that will deal with exploration and manned programs in low near-Earth orbits will be opened. We have agreed in principle that if countries are ready to participate in this and do this, the doors will be open for them, including for the countries that are now beginning to deal with outer space exploration,"
What does it really mean - for the moment only that Roscosmos would like to start cooperation with countries interested in possessing share in space station and ready to pay for it. Declaring that "club of countries" is open means that present partners are still not really interested in participating in OPSEK. NASA is involved in SLS and is more interested in extending operational life of ISS than developing new station. Partnership with ESA refers to providing launch services and technical cooperation, but in case of joint space station program there is still silence. Of course, DLR or CNES, major European space agencies could start individual cooperation with Roscosmos but still they will be more interested in possessing research laboratory than space facility. China possess own space station program with ambitious objective lift first module of new fully modular station in years 2020-2022. One of the countries possibly interested in cooperation with Russia could be India. ISRO still have not announced any news about their plans for creating independent space station and their astronauts training center in Bangalore is at the beginning of the development. Cooperation with Russia, experienced with manned missions, could be vital for Indian manned space program and change its position from launch service provider to country with manned space program and share in space station. One from Arab countries, like Saudi Arabia (with signed agreement for further cooperation with Roscosmos on June 2015) could also participate in program; in this way it could easily put its space program forward and get independent access to space. Still words of Igor Komarov are probably more advertisement of Russian OPSEK targeted for possessing foreign partners which could cover part of the needed budget - especially when Roscosmos budget is still shrinking. On March 17 2016, Prime Minister, Dmitry Medvedev ordered to cut space budget by 30% for 2016-2025 from 2 trillion rubles to 1.4 trillion rubles.