This means every six months there will be a roughly ten-day handover period where the ISS crew will surge to 11 in total – three crewmembers from a single Soyuz, and eight crewmembers from two USCVs.
This will eliminate the need to temporarily reduce the station’s crew to three during handover periods. Whilst the crew increase during handover periods will place additional strains on the station’s life support systems, during the Shuttle era the ISS routinely supported up to 13 crewmembers at a time.
The direct handover model also opens up the possibility for additional astronauts to conduct short-term visits to the ISS, as the commercial crew vehicles are being designed to seat more than the required number of four astronauts.
For instance, maintenance crews could be flown to conduct ten days of intense EVA activity, or researchers to conduct specific experiments during the ten-day period. At this time, however, this is not planned fo