Commercial Astronaut Missions to the ISS: From Concepts to Implementation

European Space Agency (ESA) astronauts’ International Space Station (ISS) flight opportunities are considered as a vital source to meet the utilisation, operation and political objectives which Europe has established for participating in the ISS programme. Recent internal ESA assessments have demonstrated that, in order to satisfy the objectives drawn up in the ESA ISS Exploitation Programme, a rate of three flights per year for European astronauts should be maintained as a minimum objective; the current flight rate is lower than this.