OPSEK

Orbital Piloted Assebly and Experiment Complex

Mission Profile

OPSEK (Orbital Piloted Assembly and Experiment Complex) was a proposed Russian modular orbital station concept, intended to be assembled from segments separated from the International Space Station before its planned decommissioning, potentially including the Russian Nauka multipurpose laboratory module and other Russian segments. Roscosmos proposed OPSEK as Russia's successor to its ISS participation, providing a foundation for a national orbital outpost that could support lunar exploration staging and deep space mission operations. The concept has remained a planning document without committed funding, and Russia's participation in ISS extension agreements has continued to delay any formal commitment to building a separate Russian station.