Crew size on the International Space Station remains a political hot potato. The Europeans and Japanese are livid that the station is limited to a permanent crew of three by the lifeboat (an old Russian Soyuz capsule that could bring down no more than three men during an emergency). With such a small crew, not much science gets done and few nations get a "turn" at sending someone into space. Worse, the only way to get anyone to the station is with a Russian Soyuz on a heavy booster (which can take three people up or down) and the Space Shuttle, which can easily carry seven people but cannot leave them all at the station and cannot stay in space indefinitely as a lifeboat. NASA studied using the X-38 crew rescue vehicle as a lifeboat, but this would cost a billion dollars and NASA cancelled it. The current theory is to build a new small Crew Transport Vehicle launched by an Atlas-V or Delta-IV which could carry three people to the station or bring four down. Assuming that the shuttle or a Soyuz delivered some of the station's seven-man crew, the Crew Transport Vehicle could take up the rest and, with the existing Soyuz lifeboat, provide everyone with a way to get down during an emergency. The Europeans, however, want a vehicle able to take seven people up or down, since they fear that relying on smaller half-crew vehicles would mean that most of the time only half a crew is on
the station. The problem is that such a vehicle would be so big you would have to design and build a new reusable launch vehicle to put it into orbit. That would take years and billions to design, test, and employ. NASA wants to rely on expendable boosters and the shuttle to take cargo and add-on modules to the station, but the Europeans want the 7-seat crew vehicle to also carry a full load of cargo, making it even bigger.Stephen V Cole