of seats on the Soyuz during 2011-2020, after the dearth of US astronaut launch capacity due to the retirement of the 7-person-capacity Space Shuttle, and seats became unavailable to Space Adventures. Russian Soyuz capsule astronaut transport to the ISS became possible once again after NASA signed contracts with two commercial carriers which began ISS transport services in 2020, thus making the excess capacity of seats from Soyuz capsule launches available to the private market once again. By mid-2020, Space Adventures had contracted for two of the available Soyuz seats in 2021.